The Sight Vol. 5

An annual Optometric Journal, THE SIGHT Volume 5, Issue 5 Published by: Nepal Optometry Students Society, 7th Executive Body Copyright Nepal Optometry Students Society

DisclaimerWe have tried our best to make this publication errorless and evidence based. Nepal Optometry Students Society disclaims all liability and responsibility to any person regarding the events or the consequences that might arise here forth as a result of reliance to any contents in this publication wholly or partly. Statements published in the journal are attributed solely to the authors as designated and not the official perspectives of NOSS in any ways. For enquiries or comments: Nepal Optometry Students Society, NOSS Institute of Medicine BPKLCOS P.O. BOX 8750 Phone: 01-4 Fax: 977-1Email: [email protected] URL: www.optometrynepal.org.np

THE SIGHT Vol. 5, Issue 5, September, 2009

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THE SIGHTVolume 5, Issue 5 September, 2009

Editorial

While browsing up the history, the term optometry was apparently first used in the 1890s to describe a profession that today encompasses independent health care professionals trained and licensed to diagnose and treat diseases and disorders of the visual system. Exploring days of yore, what we find is that it had originated from the very concept of glass and not beyond. It was the matter of primordial era when everything was different and so was the notion about optometry. Ages passed, and now this field has already crossed innumerable epoch-making milestones. Time, people and experimentation together revolutionized optometry to not but zenith, it seems now to be the hay day shortly reviewing the scenario overseas. Research has indeed been the prevailing backbone for all these credits. Coming back to Nepal, scenery is again different. Till date, 37 optometrists have been produced from Institute of Medicine, Nepal and some few are from across the border. Being a primary eye care provider, this number of optometrists seems to be a tiny drop in an ocean to serve for 25 millions of Nepalese population. On the other hand, the Global Initiative, Vision 2020:The Right to Sight mainly targets to work in the underdeveloped and developing countries like Nepal, not to mention other countless number of INGOs frog-marching to eradicate the avoidable blindness. The change is impossible unless governmental policy binds each and every useful manpower within country and its only after that for an organization are interlocked to achieve the common goal of Vision 2020. Effective machinery should be set from the national level that can proportionately address the grass-root level of people from every corner that in turn is possible only when expatriation of nationally produced expertise is thwarted. If not so, the premonition about tragic scenes cannot be wiped out when skilled manpower continue to stampede out of country and INGOs put forth their efforts in vain for long. Consequences might be worse as still thousands of people are vulnerable to go blind which could otherwise be prevented or cured; the prediction is not uncommon for poverty- laden and health-unaware public. It is our pleasure to exude the proudness for making this journal a reality. Nothing could stop it, it just flowed with time to be more scientific, novel and evidence-based. Editing, classifying and arranging articles were just out of our imagination yet it was done with a hope of golden sunshine of tomorrow. Warm gratitude is due to all whoever has helped us either by providing articles or by supporting morally/financially and by any other means. This journal unquestionably proves that optometry education has made a leviathan leap despite limitations and obstacles. But still we have got a long and long way to go

THE SIGHT Vol. 5, Issue 5, September, 2009

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THE SIGHTVolume 5, Number 1 September, 2009

In this IssueSuman Adhikari Shajan Adolph Dr. Kuldeep Raizada Prakash Paudel Jyoti Khadka01 02 05

Secretorial Desk Invited Article Coatings- A relook into this exciting segment Ocular Prosthesis: A Necessity of Ocular Disfigurement

Guest ArticlesPrimary eye care: Our achievements and future strategies A short perspective on Low vision aids for children Original Articles Induced Astigmatism in Sutureless Small-Incision Cataract Surgery using a Superior and Temporal Incision Profile of contact lens use in Mechi Eye Care Centre Profile of binocular visual status of pediatric patients presenting with the complaints of asthenopia Profile of amblyopia in children attending Sagarmatha Chaudhary Eye Hospital, Lahan School Eye Screening in Kathmandu Valley Review Articles Review on Care of Silicon Hydrogel Contact lens Eye Banking and corneal donation - Giving the Gift of Sight An overview on Coats Disease Eye Care Outreach Programs in Nepal: Who are the beneficiaries? Understanding People who are Visually Impaired Progressive addition lenses: What neophyte wearers and practitioners must know?? Management of Pediatric Cataract: A team approach Imaging of the Orbit (CT and MRI) Quality of life in low vision patients Ocular Malingering: Diagnosis and Management Pediatric Visual Impairment Stroke and Eye Family of Visually Impaired Child Clinical Pearls Know your Patients Mini-abstracts Gauri Shankar Shrestha Dr. Meenu Chaudhary Dr. Lila Raj Puri Dr. Subodh Gnyawali Dr. Sanjeev Bhattarai Nabin Paudel Ajit Thakur Surendra Dhungana Rajendra Gyawali Rabindra Adhikary Mahesh Kumar Dev Suraj Upadhyaya Sudan Puri Sanjaya Marasini Dinesh Kafle Digen Sujakhu Faithmath Nestha, Dipesh Bhattarai Nabin Raj Joshi Raju Kaiti, Sarita Manandhar17 19 21 09 14

THE SIGHT, Volume 5, Issue 5, September, 2009

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REVIEW ARTICLE

An overview of Coats DiseaseLila R. Puri, MDIntroduction Coats disease was first described by George Coats in 1908. It is a condition of undetermined etiology characterized by telangiectatic and aneurysmal retinal vessels associated with sub-retinal and intra-retinal exudation in otherwise healthy individuals. It is a sporadic nonhereditary condition that is not associated with identifiable systemic abnormalities. It has no apparent preponderance for race but has a clear predilection for sex, with 75% of cases occurring in males. The disease has been reported to occur in children as young as 4 months of age, and some speculate that there might be some manifestation of the process already at birth. The average age of diagnosis is 8 to 16 years, and among the individuals with the juvenile form of Coats disease, two-thirds develop clinical manifestation by the age of 10 years. Approximately one-third of patients do not present with symptoms until after the age of 30. Mostly the disease is unilateral (95%). Pathophysiology The pathogenesis of Coats disease is vague but probably follows a general sequence of events. The telangiectatic blood vessels (presumably congenital) have more permeable endothelial cells. Hence, they leak lipoproteins into the retina, causing retinal edema. As this material accumulates, it eventually breaks through the external limiting membrane of the retina, causing a non-rhegmatogenous exudative retinal detachment. As further lipo-proteinous material accumulates, the retinal detachment becomes bullous. The long-standing retinal detachment can sometimes lead to neovascular glaucoma and other complications. Clinical features Most patients with Coats disease present with decreased vision, leukocoria, and strabismus. The anterior segment is usually normal. However, corneal edema, iris neovascularization, and anterior chamber cholesterolosis can be seen in eyes with total retinal detachment and secondary neovascular glaucoma. The heterochromia seen in Coats disease usually is due to darkening of the ipsilateral iris from iris neovascularization. The ophthalmoscopic features of Coats disease include retinal telangiectasia, intraretinal exudation, and exudative retinal detachment. The retinal telangiectasia usually is located in the peripheral retina, most often between the equator and ora serrata infero-temporally. It is characterized by areas of generalized capillary dilation with small aneurysms that cause focal enlargement of these dilated capillaries. Telangiectasia in the macular area is uncommon, occurring in 5% of cases. Occasionally, there are aneurysmal dilatations of the major retinal arteries and veins as well. The exudation usually involves the retina diffusely in 75% of cases, often affecting areas remote from the main vascular abnormalities (with a particular predisposition for the macular region). When the macular exudation is dense in the form of a gray white nodule, visual prognosis is worse. Patients with untreated Coats disease eventually develop a non-rhegmatogenous exudative retinal detachment. It generally begins in the areas of telangiectasia and slowly progresses to involve the entire retina. The subretinal material is golden yellow and often shows refractile crystals of cholesterol. The detachment can eventually lie immediately behind the posterior lens capsule and can progress to cause anterior displacement of the lensiris diaphragm and secondary glaucoma.

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Classification (proposed by Shields et al) Stage 1 Retinal telangiectasia only Stage 3: A 12Stage 2: ABTelangiectasia and exudation Extra foveal exudation Foveal exudation B. Stage 4 Exudative retinal detachment Subtotal detachment Extra foveal Foveal Total retinal detachment Total retinal detachment and glaucoma

Stage 5: Advanced end-stage disease Differential Diagnosis ChildrenRetinoblastoma Toxocara granuloma Congenital cataract Persistent Hyperplastic primary vitreous Retinopathy of pre-maturity Norries disease Familial exudative retinopathy Retinal angiomatosis

AdultsDiabetic retinopathy Retinal vein occlusions Juxtafoveal telangiectasias Arterial macroaneurysm Vasculitis Hemangiomas Familial exudative retinopathy

Perhaps the most important differentiation to be made is between Coats disease and retinoblastoma, given the potential morbidity and mortality associated with the latter condition. The advanced form of Coats disease may present as an exudative retinal detachment and dilated retinal vessels with the appearance of a retinal mass, mimicking retinoblastoma. In fact, among enucleated eyes discovered to be misdiagnosed with retinoblastoma, Coats disease usually happens to be the most common diagnosis. Association Coats syndrome or a Coats-like response (retinal detachment with massive subretinal exudation) has been seen associated with various other systemic and ocular diseases including muscular dystrophy, branch retinal vein obstruction, retinitis pigmentosa, Hallermann- Streiff syndrome, Turner syndrome and retinopathy of prematurity. Diagnosis The best method of making the diagnosis of Coats disease is recognition of the characteristic ophthalmoscopic features. It is important to obtain a medical and family history and to examine the patients parents to help exclude conditions like retinoblastoma, ocular toxocariasis, persistent hyperplastic primary vitreous, familial exudative vitreoretinopathy, and other childhood exudative retinopathies. Ancillary studies like Ultrasonography, fluorescein angiography, and cytologic analysis of sub-retinal fluid can be helpful in substantiating the diagnosis in atypical cases. Ultrasonography is mainly of diagnostic value in cases with a retinal detachment in which exophytic retinoblastoma is a consideration in the differential diagnosis. FFA can delineate irregularly dilated, tortuous blood vessels and adjacent areas of retinal capillary dropout that characterize Coats disease. The vessels typically fill with fluorescein in the late arterial or early venous phase and show progressive leakage of dye into the adjacent retina and sub-retinal space. In late-phase angiograms, there is persistent confluent hyperfluorescence of the exudate in the retina and sub-retinal space. Computed tomography and magnetic resonance imaging may also be useful in detecting masses, and computed tomography is very good at demonstrating calcifications.

Treatment THE SIGHT, Vol. 5, Issue 5, September 2009 Page 5

The goal of treatment is to obliterate the telangiectasis and stop the exudation. Multiple treatments may be required. The treatment modality depends on the location of the lesions and the age of patient. According to a recent report, the proposed classification of Coats disease can be helpful for selecting treatment and predicting the ocular and visual outcomes. Stage 1 disease (telangiectasia only) Can be managed by either periodic observation or Laser photocoagulation. Stage 2 disease (telangiectasia and exudation) Cryotherapy or Laser photocoagulation depending on the extent of the disease Stage 3A disease (subtotal retinal detachment) Laser photocoagulation or cryotherapy. Stage 3B disease (total retinal detachment) Can be managed with cryotherapy if the detachment is shallow, but surgical reattachment may be required if the retina is immediately posterior to the lens. Stage 4 disease (total retinal detachment with glaucoma) Often best managed by enucleation to relieve the severe ocular pain. Patients with stage 5 disease Generally have a blind, but comfortable, eye and require no aggressive treatment. References1. 2. 3. 4. 5. 6. Egerer , Tasman W, Tomer TL. Coats disease. Arch Ophthalmol. 1974;92:109112. 156 Reese AB. Telangiectasias of the retina and Coats disease. Am J Ophthalmol. 1956;42:18. Asdourian G. Vascular anomalies of the retina. In: Peyman GA, Sanders DR, Goldberg MP, eds. Principals and Practices of Ophthalmology. Vol. 2. Philadelphia: WB Saunders; 1980. Shields JA, Shields CL, Honavar SG, et al. Classification and management of Coats disease: the 2000 proctor lecture. Am J Ophthalmol. 2001;131:572583. Tarkkanen A, Laatikainen L. Coats disease: clinical, angiographic, histopathological findings and clinical management. Br J Ophthalmol. 1983;67:766776. Woods AC, Duke J. Coats disease. I. Review of the literature, diagnostic criteria, clinical findings, and plasma lipid studies. Br J Opthalmol. 1963;47:385412. CRB1 in inherited blindness. Novartis Found Symp. 2004;255:6879.

Lila R. Puri, MDOphthalmologist EREC-P, Sagarmatha Chaudhary Eye Hospital, Lahan, Nepal Email: [email protected]

THE SIGHT, Vol. 5, Issue 5, September 2009

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REVIEW ARTICLE

Eye Banking and corneal donation - Giving the Gift of SightDr. Meenu Chaudhary, MDThe joy of sight restoration is incomparable with anything in the world. It is like giving life back to the dead. Anyone who has spent time in Asia or Africa can invariably recall a vivid image of a blind beggar, sometimes an elderly person but frequently a child with opaque corneas, haunting the bazaars and marketplaces of cities and villages. The spectre is so common that it almost passes unnoticed, but these individuals who are bilaterally blind represent only a small fraction of the millions who suffer monocular blindness as a result of corneal trauma and subsequent microbial keratitis. With the global figure of blindness rapidly approaching 40 million, attention naturally is focused on cataract, which is responsible for 50% or more of all visual disability. While corneal blindness in the developing world has traditionally been attributed to Trachoma, Xerophthalmia, Measles, Neonatal ophthalmia and Leprosy, Thylefors contends that the importance of superficial corneal trauma in agricultural work, which frequently leads to rapidly progressing corneal ulceration and visual loss, has been overlooked as a worldwide cause of monocular blindness. In National Blindness Survey (1981), corneal trauma and ulceration were found to be the second leading cause of unilateral visual loss after cataract, accounting for 7.9% of all blind eyes. In Malawi, Tanzania and Bangladesh corneal scarring was found to be responsible for 39-55% of all cases of unilateral blindness. Undoubtedly, true estimates of the magnitude of blindness from corneal ulceration in the developing world remain elusive because of the unilateral nature of keratitis. A comparison of population based studies in the USA and India indicates that there is at least a tenfold higher incidence of corneal ulceration in India. In absolute numbers, microbial keratitis in the developing world is a previously undocumented significant cause of THE SIGHT, Vol. 5, Issue 5, September 2009 monocular blindness. As such, even by conservative estimates, it is responsible for well over one and a half million new cases of unilateral blindness worldwide each year. Corneal blindness is a major form of visual deprivation in developing countries. A high percentage of these individuals can be visually rehabilitated by corneal transplantation, a procedure that has very high rate of success (about 90%) among organ transplants. Quality of donor cornea, the nature of recipient pathology and the availability of appropriate postoperative care are the factors those determine the final outcome of this procedure. On December 7, 1905, Dr. Edward Zirm performed the first successful and permanent corneal transplant. The procedure was performed on Alois Glogar, a farmer who was suffering from the consequence of chemical eye burns. The cornea was of an 11-year-old boy named Karl Brauer. Understanding that the second major cause of blindness in Nepal is corneal blindness and that an estimated 1,200 men, women and children could be helped each year through the establishment of an eye bank, Nepal Eye Bank was established on September 16, 1994 at Tilganga Eye Centre with the generous help of IFEB and Indian Eye Bank, which reached out in a generous caring way to bring hope and vision to the citizens of Nepal. In 1999 Temple Eye Banking was started by Tilganga eye hospital for procuring cornea. Eye Bank An "Eye Bank" is a nonprofit community organization governed by a Board of Directors or Trustees constituted by community representatives. Structurally, it has administrative and medical Page 7

components. The entire operation is supervised by a Medical Director, who is usually a well qualified corneal surgeon assisted by an Administrator and other staff on the administrative aspects and trained technicians on the medical issues. Functionally, the administrative section is responsible for public awareness programs, liaison with government, local voluntary and other health care agencies and fund raising. The medical section deals with the entire technical operation of the eye bank. Tissue harvesting, tissue evaluation, tissue preservation and tissue distribution represent these activities. Each of these should be carried out following medical standards of highest quality. Any deviation from accepted medical standards can result in devastating complications. Procurement and supply of donor cornea to the corneal surgeons is the primary goal of eye banks. The Eye Bank is responsible for the collection and processing of donated tissues, their distribution and is also liable for an extensive public awareness program that can dramatically improve donation rates and public receptivity to eye donation. Moreover, it performs necessary blood investigation for HIV/AIDS, Hepatitis B, Hepatitis C and Syphilis of the Donor. An eye bank should have communication facilities, access to equipment such as slit lamp and laminar flow hood, surgical instruments, sterilization facilities, serology laboratory, preservation media and appropriate transportation system. Round-the-clock coverage by fully trained technicians is essential. All eye banks should be part of a nationwide network to facilitate optimal utilization of all corneas found suitable for corneal transplantation.

Corneal donation all begins with a donor and a donor family. Death of a loved one is never easy. The gift of eye, organ and tissue donation not only benefits the transplant recipients, but also eases the pain and grief of a donor family by offering a measure of comfort. When preliminary donor suitability has been determined and consent has been granted by the family, trained health professionals begin the process of eye recovery. This surgical procedure, known as enucleation, is usually accomplished within six hours of death and preservation of the corneas generally takes place within 12 hours of death. After the eyes have been delivered to the eye bank, they are carefully examined, and the corneas are surgically removed in a sterile environment. The corneas are placed in protective sterile chambers containing a preservation media that enables refrigerated storage for a number of days. Surgeons are notified of the availability of suitable corneas. Corneal matching is not necessary, as a lower level of rejection occurs than in solid organ transplant probably due to the avascular nature of the cornea. Nevertheless, rejection is always a possibility. If a transplant fails, the patient can undergo another corneal transplant at a late time. Our appeal Take pledge to donate your eyes Motivate and educate others about eye donation. Call your nearest eye bank. Restoring sight through the promotion and advancement of eye banking, thanks to heroic and compassionate donor families, many have received The Gift of Sight.

Dr. Meenu Chaudhary, MDLecturer, Cornea specialist BP Koirala Lions Centre for Ophthalmic Studies, IOM Maharajgunj, Kathmandu Email:

Before

After


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Understanding Visually Impaired People- Bhattarai

Frequently Asked Questions about Corneal Transplantation What is Corneal Transplantation? A Corneal transplant is a surgery which replaces the opaque cornea with a clear cornea obtained from a human donor eye. 2. How does a cornea become opaque? Infection Injuries Malnutrition Congenital/Hereditary 3. Who can be an eye donor? Practically, anybody from the age of 1 year can be a donor. There is no upper age limit. Spectacle wearers, people who had had cataract surgery, diabetics and hypertensive, and even people blind from retinal or optic nerve disease can donate their eyes. The ultimate decision about usage for transplantation will be made after evaluation. 4. Can the next-of-kin consent to a donation if the deceased family member hasn't signed a pledge form? Yes. 5. How can I be of help on the death of a close relative or friend? Motivate the next of kin of the deceased person to donate their eyes. Eyes need to be collected within 6 hours of death. Call your nearest eye bank at the earliest. You are authorized to donate the eyes of your beloved relatives at the time of their death, even if a pledge for donation has not been made earlier by the deceased. 6. What should I do till the Eye Donation team arrives? 1.

Keep both eyes of deceased closed and covered with moist cotton. Switch off the overhead fan. Raise the head end of the body by about 6 inches, if possible - to decrease the incidence of bleeding during the removal of theeyes.

If possible, instill antibiotic eye drops periodically.7. Who cannot be a donor?

Death from unknown cause. Death due to infectious caused viz. Rabies, Syphilis, Infectious Hepatitis, Septicemia and AIDS. Any frank ocular infection, previous refractive surgery.8. Can the whole eye be transplanted? No. Only the cornea and sclera can be transplanted. However, the entire eyeball is enucleated, to enable the corneo-scleral disc to be fashioned surgically in a sterile environment. 9. Can a living person donate his/her eyes? No. 10. Can the recipients be told who donated the eyes? No. The gift of sight is made anonymously.


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Understanding Visually Impaired People- Bhattarai


REVIEW ARTICLE

Understanding Visually Impaired PeopleDr. Sanjeev Bhattarai, M.Optom, O.D Low vision or visual impairment is a term used to describe varying degrees of vision loss that can not be corrected by medications, surgeries or conventional glasses and contact lenses. World Health Organization (WHO) defines - "A person with low vision is one who has visual acuity of less than 6/18 to light perception, or a visual field of less than 10 degrees from the point of fixation but who uses or is potentially able to use vision for the planning and/or execution of a task". Visual disturbances in low vision patients are loss of central and peripheral vision, overall blurred vision, night blindness, light and glare problems etc. Examination and Evaluation: Focus should be given on patient's concerns as people are extremely variable and all have individual interests and lifestyles. Reading, watching TV, activities of daily living and recreations, mobility, work and financial support, psychosocial conditions etc should be specially considered. Examination begins with vision assessment for near and far, contrast sensitivity function, visual field, glare test, color vision, binocular vision, refraction etc. Management: After examination procedures, depending on the patient's needs both optical as well as non optical devices can be given. Patients should be advised to optimize lighting conditions and contrast whenever it is required. Refraction should be aimed to obtain the best possible visual function. For near activities reading glasses, hand held and stand magnifiers, bar magnifier, Fresnel magnifier, reading telescopes, CCTV can be provided with proper training to utilize the instruments. For distance, telescopes can be given with varying magnification. Non-optical devices for low vision patients include many assistive devices like talking watches/clocks, writing guides, liquid level indicators, tactile controls, large playing cards, glare control devices, posture and comfort maintenance devices, THE SIGHT, Vol. 5, Issue 5, September 2009 written communication devices, sensory and audition devices, large print syringes etc. Low vision intervention can be very beneficial in diseases like Albinism, Diabetic retinopathy, Age related macular degeneration, High myopia, Aniridia, Retinal coloboma, Optic atrophy etc. Ocular conditions in which low vision devices can still be tried include Nystagmus, Advanced glaucoma, Microphthalmos, Congenital cataracts, corneal dystrophy, Marfan's syndrome etc. Understanding problems of visually impaired The impaired person waits for someone else for information. He/she depends more on verbal remarks. He/she needs more time to do the task. Do not always place objects in the person's hand. The person should be encouraged to look for the object and reach out for it. To make them adapt to their environment, ask relatives and friends to explain and describe objects and things happening. Describe these things in words that the person can understand. The clinician should describe him/herself after entering/leaving the room as they may not be aware of another person nearby or in a room. Provide objects or materials with contrasting colors that make activities easier. People with certain eye conditions are nearly blind at night or in dim light. They may not have enough vision to move safely by themselves or do their normal activities as they could do during the day. A torch or flashlight is useful. It is often difficult to see steps or changes in the level of floors or the ground. Changes in the levels can be marked. Objects are usually easier to see when they are large and close. Page 10

Understanding Visually Impaired People- Bhattarai They find it easy to detect colorful objects. Glare makes it difficult for all people to see. The light in the environment and on objects can affect how well objects can be seen. Sitting close to TV at a distance which is comfortable for the eyes will not cause any damage. It is not wrong to squint and view the faces or objects if someone sees better by doing so.

Some myths and suggestions for visually impaired which should be explained to the patient and relatives are as follows: The brightest possible light is not necessarily the best. Visual effort will produce no ocular damage though there may be an initial fatigue, which will be overcome by regular usage. The more the visually impaired person uses his residual vision, the better the brain will interpret. Its good to sit in natural day light and read initially till the adaptation to the low vision device occurs.

Conclusion: A low vision patient should be assured of some attention with patience to explore the possibilities of assisting him/her even if they are of very little help. The modern optical, non-optical and electronic devices though cost prohibitive, have opened the doors to light from darkness.

References:1. Essentials of low vision Richard L Brilliant

2. Understanding low vision Randall T Jose 3. Practice of low vision-A guide book- E. Vaithilingam 4. Oxford hand book of Ophthalmology. 5. Essentials of Ophthalmology-Samar Kumar Basak

Dr. Sanjeev BhattaraiInstructor Optometrist BP Koirala Lions Centre for Ophthalmic Studies Institute Of Medicine Email: [email protected]


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Eye Care Outreach Programs in Nepal Gyawali


REVIEW ARTICLE

Eye Care Outreach Programs in Nepal: Who are the beneficiaries?Subodh Gnyawali, ODBy making the elimination of needless blindness its prime objective, VISION 2020 has introduced a major paradigm shift in the planning and delivery of eye care. With adoption of Vision 2020 program by the Government of Nepal, for many service providers and other stakeholders in this global initiative, this is both a challenge and an urgent call to move quickly from reaching as many as we can strategies to new approaches that insist on doing it right and enough to make a lasting impact. It is quite challenging to make it happen in the poorest and neediest rural communities of Nepal with dysfunctional infrastructure, limited access to and use of existing eye care services. Outreach should be defined as the provision of a specialized service to a location outside the normal service catchment area of the hospital. To be optimally effective, outreach strategies must be grounded in, and guided by, a clear understanding of the inequitable nature of many eye care services. Those who need eye care services the most are often the last to have access to them, if at all. This may be so even when these services are brought closer to their communities, though several studies have shown that the utilization of health services by deprived groups increases when service providers reach their locality. So, unless specific proactive measures are put in place to seek them out, eye care outreach programs will remain ineffective in delivering services to the un-served. Different eye health institutions sometimes, with support from international organizations, have conducted several outreach programs (either surgical, screening, mobile eye camps or community based rehabilitation camps) in different parts of the country at different times. Most outreach programs can easily result in increased number of patients seen or offered surgery. The real challenge, however, is ensuring their administrative, organizational THE SIGHT, Vol. 5, Issue 5, September 2009 and financial sustainability for long term, something that only few institutions or organizations have done successfully so far. The current gap between eye care providers and the many blind and severely visually impaired needing their services is unacceptable, and could be best bridged through the establishment of permanent eye care structures and services. Some of the major barriers for blind people are actually within the first 100 meters of their front door. These communities are isolated; suffer from poor infrastructure, and a low-density population, which prohibits the establishment of a high volume surgical unit. The most effective way to reach these communities has been to train and integrate primary eye care workers into the existing primary health care systems. Ideally, a resident of these communities is identified and trained for this work what most projects call a community-based rehabilitation (CBR) worker. These primary eye care workers are best placed to penetrate the 100-metre barrier that exists around a blind persons home. Non Governmental Organizations who conduct free eye camps and provide eye glasses only with the idea "providing some care is better than providing none" are at times counter productive and can prevent patients from seeking eye care for other ophthalmic conditions. Such short term intervention can be wasteful, unethical, and harmful and often serve as medical tourism. They fail to partner with local health care bodies and undermine the local health care system. Though few would question the honorable intentions behind these types of interventions, short-term missions rarely produce tangible, lasting medical benefits in local communities. Rather, they tend to be self-serving, ineffective, and provide only temporary, limited care without addressing the fundamentals of eye care needs. Page 12

Finally, there is generally no follow-up or quality control with these types of trips; most of these missions identify their success based on whether a patient smiles upon receipt of the glasses, or whether the team is invited back for a future mission. These are not effective metrics for evaluating success. Eye care programs must eliminate patient barriers to care by fully funding surgeries, bringing eye care services to the patients, providing transportation to the eye hospitals for surgery as needed and educating communities about blindness elimination. Prescribing eyeglasses only during a short-term intervention to population will leave them believing they have received a complete ophthalmic exam, no matter how cursory the vision screening, even if they are explicitly told otherwise. If a patient with cataracts, for example, is told that eyeglasses will not correct their sight, but an option for subsidized or free cataract surgery is not provided, the patient will continue to believe that nothing can be done to restore their sight. Random spectacle distribution, above that by a non eye care professional, breaks the chain of patient care and is counterproductive as it can cause discomfort to the wearer and create or perpetuate distrust of health providers. Training community members to prescribe eye glasses can have a negative effect on the identification and treatment of curable and treatable eye diseases. Referring patients from rural communities to their local eye doctor without reducing the barriers will not enable their access to locally available resources and quality eye care. Of all the worst effect is seen with short term surgical missions. There is no provision of follow up care which

Eye Care Outreach Programs in Nepal Gyawali is very important to tackle post-operative complications. Local doctors are often left to deal with complications following low quality surgeries, which is both timeconsuming and a financial burden to the local clinics. Such interventions are thus minimally effective at best, as they do not encourage community members to seek regular eye care, nor do they build local capacity. Another disastrous effect is seen with the distribution of contaminated and expired medicines in outreach clinics. Expired medications often degrade into toxic substances, and lowered drug efficacy may lead to patients receiving incorrect or ineffective dosages. With regards to ophthalmic surgery, the post-operative use of ineffective expired drugs can lead to infection and the consequent loss of vision. Particularly with antibiotics, expiration and contamination can not only harm patients, but contribute to the ever-worsening global problem of microbial resistance. Thus such communities may serve as dumping zones for pharmaceutical junk. Some of the key components of a good outreach program can be summarized under following heads: 1. Careful planning of the program 2. Community involvement and ownership 3. Government involvement and leadership 4. A good monitoring and evaluation system 5. A structure and clear mechanisms for dialogue, problem-solving and co-ordination among all stakeholders Subodh Gnyawali, ODMPH Student, Institute Of Medicine Maharajgunj, Kathmandu, Nepal Email: [email protected]


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Coatings - Adolph


REVIEW ARTICLE

Coatings- A Relook into This Exciting SegmentShajan Adolph, Fellow in Optometry, FIACLE Lens coating has become a hot topic in the optical fraternity and one may wonder why so much of hype on this segment. But the reality is that it requires much more attention than this as this segment is not yet established well in many markets and countries. Spectacles are considered as a friendly aid to help us in achieving better visual performances. Considering the modern life style and work profile, one is constantly engaged in many activities and almost all kinds of jobs require precise vision and the visual demand is on rise on daily basis. Improved visual quantity and quality, better contrast, reduced reflections and glare, better color perception etc. are becoming mandatory for every one. ECP (Eye Care Professionals) need to note and accept the change that new generation is looking for an opportunity to SEEING WELL and not just seeing. Unfortunately the regular pairs of uncoated lenses are not equipped to fight against the common enemies of spectacle lenses like scratches, reflections, smudges and deposits and hence the need of AR coating comes to the scene. Coating on lenses started in 1950s with glass lenses and later plastics and polycarbonate lenses also joined in due time, offering many options for the ECP. While it is true that coating provides much value addition to the lenses, the coating process is a very complicated one. The success of coating lay up on many factors including the right selection of materials for coating, process control in coating unit, quality of the lens materials etc. Thanks to the advanced technology and advancements in the software industry, more precision is achieved today in the coating and we have a good number of labs providing quality lens coating. Coatings can be broadly divided into the following categories: Hard coating or commonly called Scratch resistant coating (HC) Hard Multi Coating or Anti-reflection coating (ARC) Hard-Coatings: Hard coatings are meant to protect the surface of the lens by resisting the scratches and hence increase the life of the lens. Customers change their lenses only after two or two and half years on average. Only a good hard coat can withstand the wear and tear of such a long time. From the umpteen products available in the market at different price points, it is wise to provide a good quality hard coat to protect the investment of customers. Promoting hard coat requires a good understanding of the technology, materials and process as these are the main factors behind the success of HC. It is difficult to filter out a good HC from an ordinary one in the counter of an optical outlet as all lenses look transparent or WHITE. There are many lab tests which tell us the quality and efficiency of the HC but there are no counter tests to check the same. Usually the counter sales team gets the confidence on the products from the response of the end users. Hard Coating is meant for resisting the scratches which comes while handling the lenses and can not be termed as scratch proof coating. It is a fact that the lenses, especially plastic segment became more user friendly after the advent of HC. There are different materials available for hard coating and processing is also an important factor. The bonding between basic monomer and hard coating varnish has to be good for the long lasting performance of the lens. ECP need to understand the features and benefits of the products. There are few Page 14


Coatings - Adolph proven products in the market which are trusted and certified both by wearers and Opticians. Anti-Reflection coating One of the most anointing concerns of the spectacle wearer is the reflection from the lens surface which not only reduces the quality of vision but also hampers the cosmesis. Due to the changed life style one is exposed to different kinds of lights, contrasts, ghost images, reflections and glare etc. While it is true that all spectacle users suffer from these problems, the issues are much more with people who spend maximum time infront of the computers/monitors and also with night drivers. Reflections When we see an object, the entire amount of light beam from the object should pass through the lens and focus on retina. But this sort of ideal scenario does not exist and some amount of light gets reflected back from the lens surface. Reflections depend on many factors like refractive index, thickness and curvature of the lens, lens surface quality etc. Reflections with ghost images pull down the quality of vision and it has to be addressed well to have better visual experience. How does AR coating work? AR coating has to be done after the hard coating and multiple layers of different chemicals (oxides) are applied on either surface of the lenses in a highly controlled atmosphere, using vacuum technology. The process runs under stringent quality controls as variations in the temperature, humidity etc. can affect the quality of ARC. After ARC is applied, some manufacturers use hydrophobic coating which makes the lens surface easy to clean. Manufacturers have different materials to use for coating and depending on the chemical used, lens get a residual color which helps us to differentiate AR coated lenses from uncoated or hard coated lenses. The residual color has no connections with the efficacy of the coating however most preferred colors are green and blue. The functioning of AR coating is simple. The reflected rays from the lens surface can be considered as positive waves and the AR coating creates negative waves and THE SIGHT, Vol. 5, Issue 5, September 2009 cancels the reflection. In scientific terms it is called Destructive interference. The function of ARC may look simple but the processing is very complicated needing man, machine, money and time. The advancements in the tools and software helped us to achieve a greater level of standards in production. The combination of lens material and coating ensures a better durability of the coating and it is great challenge to the manufacturer. Making quality products available at best price and matching the delivery expectation from the outlets are the other challenges. AR Coating features and benefits A good ARC ensures elimination of reflection and increases light transmittance which ensures that you are seeing well and you are seen well as well. Glare reduction provides better visual quality and improved contrast is helpful in better color perception. The multiple layers also provide better surface clarity. ARC is beneficial not only for computer users but also for all spectacle wearers. Each and every one can have better vision with the help of ARC and hence the ECP need to advice ARC for the entire spectacle users and help them to see the world better. Why ARC use is less in our country? The use of ARC in the SAARC countries is very less compared to other Asian countries and the major reason for this is the lack of awareness. While some ECP are extremely well on this segment there is another group of practitioners who are not dealing with this at all. An active recommendation form the side of ECP along with the marketing support from the companies can bring up the use of ARC. Today companies like Essilor join with optical fraternity to promote this segment well. ARC Cost a concern At times the counter sales team members are not in a position to explain well about the benefits of ARC and the consumers either get a negative message or they do not find any value with this coating. As we know that cost is a relative term and if properly explained the benefits by the counter sales team, consumers get better idea about ARC and it results in a better sale. The cost is justified if consumers understand the benefits of ARC. Education on ARC is a major task taken by many Page 15

Coatings - Adolph companies as this will help towards making ARC a preferred option for the end users. ECP has a wide choice of products available now in market ranging from the lowest range to premium. A good quality product is selected on the basis of its performance, technology, availability and brand value. The negative remark on ARC is the coating peel off and it is mainly due to the poor selection of products, improper use of lenses by consumers and at times even due to the poor quality of lens coating. We have better quality of coating nowadays which are very durable and ECP can make a wise choice after considering few parameters. Essilors Crizal is one of the leading and most trusted ARC products in the world. A good quality product protects the investment of the end users while delivering the benefits. Business Opportunity A recent survey done by Essilor reveals that ARC penetration is too low in many Asian countries for e.g. in India it is only 6% while other countries like Japan has 98% penetration. The survey results also reveal some interesting factors like more than 90% of people are willing to buy ARC and 98% of the end users are willing to buy the lenses again. The potential for ARC is very high and ECP have to capitalize this opportunity and prepare their sales team for the change. Future of ARC The retail business is emerging well in all spheres and economy is also showing a great future ahead. Consumer awareness, organized selling styles, educated sales team, better products etc are all predicting a bright future for this segment. ECP have to gear up for this and equip themselves to welcome the new era of ARC.

Shajan AdolphFellow in Optometry, FIACLE Head of Professional Services, Essilor India Email: [email protected]


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Review on care of silicon hydrogel lenses - Shrestha


REVIEW ARTICLE

Review On Care Of Silicone Hydrogel LensesGauri S. Shrestha, BOptom, MOptomIn the last few years, silicone hydrogel contact lens has surpassed tremendous breakthrough over traditional hydrogel lens as daily or flexible wear and has opened the hope of continuous wear for 30 days. These new generations of "super-permeable" contact lenses can transmit unprecedented amounts of oxygen to cornea that breathe six to seven times more oxygen than previous lenses. U.S. Food and Drug Administration (FDA) has approved Day & Night (CIBA Vision) and PureVision (Bausch & Lomb) to be worn for 30 days. Acuvue Oasys (Johnson and Johnson), and O2Optix (CIBA Vision) are approved for overnight wear of six nights consecutively.1 When a lens remains on the eye for a long period; metabolic debris, including CO2 and lactate, forms under the lens. Exotoxins produced by normal eyelid flora may also accumulate and are effective in inciting inflammatory reactions. So, removal of post-lens ocular waste is still not applicable for higher Dk materials designed for continuous wear and lens care regimen is important for silicone hydrogels also.2 Currently, five solutions have an FDA indication for silicone hydrogel lenses: Aquify MPS and Clear Care (CIBA Vision); Opti-Free Express and Replenish (Alcon); and ReNu with MultiPlus (Bausch & Lomb). There has been marked growth in the use of no-rub care regimens. This idea primarily came about because of its well recognition that patients are generally noncompliant with instructions relating to the rub-and-rinse step, with many merely removing the lens from their eye and dropping it into their care regimen overnight. These no-rub products were developed to work optimally on the large amount of loosely bound, non-denatured protein that is found on many conventional lens materials. Unlike conventional lenses, silicone hydrogels deposit small amounts of denatured proteins and THE SIGHT, Vol. 5, Issue 5, September 2009 increased amounts of lipid and thus there is growing evidence to suggest that patients using silicone hydrogels should consider rubbing their lenses with their care regimen.3 Antimicrobial and Disinfection Efficacy Though, the risk of infection in the extended wear lenses is comparable to that of older lens types worn for fewer nights, acanthamoebal attachment to the silicone hydrogel is greatly significant. The inherent characteristics of the polymer or a side effect of the surface treatment procedure are supposed to be the cause. 4 Currently there are no agreed test organisms or standards to which solutions must conform in their efficacy against acanthamoeba. In fact, multipurpose solutions having an effect on acanthamoeba works by simple physical removal or some level of disinfection. 5 According to the stand-alone primary criteria of FDA Guidelines, ReNu and ReNu MultiPlus meets the acceptance criteria for stand-alone disinfectants against all challenging organisms: Staphylococcus aureus, Serratia marcescens, Pseudomonas aeruginosa, Candida albicans, and Fusarium solani.6 ReNu MultiPlus (Bausch & Lomb), AOSEPT (CIBA Vision), and Opti-Free Express with Aldox (Alcon Laboratories) are the only lens care products that met the stand-alone criteria for all required microorganisms within their minimum recommended disinfection time (4 hours). 7 Surface Deposit Proteins, lipids and mucin deposit rapidly after lens insertion. Tear proteins include lysozyme, lactoferrin and albumin, with lysozyme accounting for 90% of the total lens protein deposits. In its natural state, lysozyme is a bacteriolytic enzyme, however once it deposits on a lens, it gets denaturated, which may incite an immunological response, such as contact lens papillary Page 17

conjunctivitis (CLPC). This positively charged protein is also easily absorbed by negatively charged materials with relatively large pore size. This is more prominent in HEMA material combined with group IV polymers. Most of silicone hydrogel falls under the FDA categories I & III. Silicone hydrogel materials, on the other hand, have shown reduced protein deposition, but they show a greater percentage of denatured lysozyme.8, 9 Jones and colleagues9 reported silicone hydrogel contact lenses deposit more lipid than HEMA soft lenses do. The hydrophobic nature of silicone is presumed to be the responsible factor.8 Lipids deposited on the surface of high water non-ionic hydrogel as well as low water ionic silicone hydrogels are factors for the increased corneal staining.5 Lipids are easily removed with digital rubbing of a surfactant cleaner. They are also readily dissolved in solvent (alcohol) based cleaners such as MiraFlow (CIBA Vision).10, 11

Review on care of silicon hydrogel lenses - Shrestha Wettability Silicone hydrogel lenses are notorious for their high wetting angles and poor wettability. Surfactants found in contact lens solution help to increase wettability. A surfactant agent has both a hydrophilic and a hydrophobic end to its structure. In the case of a surfactant wetting agent, the hydrophobic end interacts with the dry hydrophobic lens surface, allowing the lens surface to regain hydrophilicity. A surfactant wetting agent decreases surface tension, significantly reducing dry areas. The substantivity (the length of time the surfactant stays on the lens) determines the longevity of this effect. Some large molecular proteins, like albumin, actually aid in the wetting of the lens surface. Smaller proteins, such as lysozyme and mucin, have no impact on the wettability of silicone hydrogel lenses.8 Lens and Solution Compatibility All contact lens materials may not be compatible with all

Solution & lens combination staining on selected lenses Unisol saline Acuvue 2 Pure vision Acuvue oasys O2 optix Focus daynight 1% 2% 2% 2% -4 Opti-free express -6% 3% 2% 4% Polyquad Opti-free repleniSH 5% 7% 5% 5% -ReNu MultiPlus 25% 6% 10% 7% 6% Biguanides Equate Complete moisture plus 2% 48% 5% 18% -

Aquify

1% 71% 12% 41% -

-21% 1% 7% --

1. Acceptable staining (20%) 2. Andrasko G, et al. Compatibility of Silicone Hydrogel Lenses with Multi-Purpose Solutions. ARVO Poster, 2006

Wearing Modality Although many patients aspire to achieve 30 days of continuous lens wear, not all of them can successfully keep a lens on the eye for one month at a time. Therefore, a contact lens care regimen truly is a necessity for all modalities.10 With continuous wear, one key to avoiding an adverse response is to ensure that only a clean and disinfected lens is inserted into the eye. To prevent an inflammatory adverse event, many practitioners encourage their patients to only wear their contact lenses on a daily wear basis when they're ill and to return to overnight wear of their lenses when they're completely well.10 THE SIGHT, Vol. 5, Issue 5, September 2009

lens solutions. Biocides have different uptake and release patterns depending on the material, with the greatest corneal staining between two and six hours after lens insertion. 8 Opti-Free RepleniSH (Alcon), AQuify and Clear Care (CIBA Vision) have specific FDAapproved, "silicone hydrogel" labeling on the packages. UltraCare (AMO) is specifically contraindicated for use with PureVision lenses on the package insert.8 Polyhexymethylene biguinide (PHMB) disinfecting agents are most commonly implicated in solution-related corneal staining. PHMB has shown significantly more staining and tarsal plate changes compared with hydrogen peroxide and polyquaternium-based solutions.8 Page 18

However, not all PHMB solutions cause cytotoxicity with all lenses.8 Studies with silicone hydrogels indicate that the corneal staining seen is frequently annular in appearance, typically increases in severity over a 4-week wearing period.8 At the formulations of Aquify compared to Equate5, the concentration of PHMB is identical. The staining differences (Table) are influenced by other components in the formulation12. Although corneal staining is not a sight-threatening event, it probably does affect long-term wearing comfort. The compatibility of different lenses with different solutions in relation to corneal staining is presented in the following table: Last Message Regardless of refractive error, patient can get benefit of novel contact lens materials provided specific lens care recommendations are given to every patient based on the surface characteristics of the material, the patient's lifestyle and wear schedule. This is especially concerned while switching a patient from a conventional contact lens because previously used lens care solutions may no longer be appropriate. Observation of corneal staining can serve as a clue to incompatibility issues and compliance with contact lens care. Consideration of the lens care is an integral part of success with silicone hydrogel contact lenses. Not all lens care solutions are created alike and not all contact lens materials behave the same.

Review on care of silicon hydrogel lenses - Shrestha References:1. 2. 3.Liz Segre; Silicone hydrogel contact lenses; www.allaboutvision.com/advisorybrd.htm#Joseph Brian Chou, OD, FAAO; Are Silicone Hydrogel Contact Lenses Overrated? Contact lens spectrum Lyndon Jones, PhD FCOptom DipCLP DipOrth FAAO (DipCL) FIACL; Emerging Trends in New Care Regimens for Silicone Hydrogel CLs Materials, Silicone Hydrogel Tara K. Beattie et al; Enhanced attachment of Acanthamoeba to extended-wear silicone hydrogel contact lenses: A new risk factor for infection? Ophthalmology, Volume 110, Issue 4, Pages 765771 (April 2003) Nick Atkin; Development in lens care solutions; CET module C3 113; Optician; Feb 3,2006, No 6037Vol 231 Lever AM, Miller MJ; comparative antimicrobial efficacy of multipurpose lens solutions using the FDA revised guidance document for industry: Stand alone primary criteria. CLAO J. 1999 Jan;25(1):52-6 Miller MJ et al; Disinfection efficacy of contact lens care solutions against ocular pathogens; CLAO J. 2001 Jan;27(1):16-22 Christine Sindt, O.D., F.A.A.O; Caring for silicone hydrogel lenses; Optometry management; issue: july 2006 Jones L, Senchyna M, Glasier MA, Schickler J, Forbes I, Louie D, May C. Lysozyme and lipid deposition on silicone hydrogel contact lens materials. Eye Contact Lens. 2003;29(1 Suppl):S75S79; discussion S83-S84, S192-S194. Smythe, Jennifer L, A New Generation of Contact Lens Care; Optometric Management, Mar 2005 Lyndon Jone, PhD FCOptom DipCLP DipOrth FAAO (DipCL) FIACLE; Silicone hydrogel and choice for care regime; Silicone Hydrogel; March 2005 Lens-Solution Interactions; Contact lens spectrum; August 2006. Schafer J, Barr J, Mack C. A characterization of dryness symptoms with silicone hydrogel contact lenses. Optometry & Vision Science; 2003.

4.

5. 6.

7. 8. 9.

10. 11.

12. 13.

Gauri S. ShresthaTeaching Assistant BP Koirala Lions Centre for Ophthalmic Studies IOM, TUEmail: [email protected]


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Profile of Amblyopia - Joshi


ORIGINAL ARTICLE

Profile of amblyopia in children attending Sagarmatha Chaudhary Eye Hospital, LahanNabin Raj JoshiBackground Amblyopia is one of the common causes of childhood visual impairment. The information regarding the prevalence of sub types of amblyopia can help in the prioritized management of this condition and the profile can give a general idea about a case of pediatric amblyopia, more rationally. Methods This was a prospective hospital based observational study, evaluating the clinical profile of the amblyopic patients presenting to the pediatric OPD of Sagarmatha Chaudhary Eye Hospital (SCEH), Lahan. Results Out of 50 patients enrolled in the study, 62% (31) were of Indian nationality and 58% (29) were male. The mean age of the sample was 10.54 3.56 (mean standard deviation) years. The mean age of the first presentation was 8.32 3.56 years. The mean difference between the first onset of symptoms and presentation was 3.44 2.17 years. The main cause of amblyopia was hyperopic isoametropia (38%, n=19). Conclusions The lack of awareness about the disease and the consequent late presentation are significant hindrances to our health system if amblyopia is to be tackled well in the future .

Introduction Amblyopia (Gk. Blunt eye) is generally used in a restricted sense to denote reduced vision in an eye in the absence of any ophthalmoscopically detectable retinal abnormality or any disorder of the afferent visual pathway which might cause the defect.1 Amblyopia can be classified as functional or organic (lesions in the visual pathway). Either form sense deprivation or abnormal binocular interaction or both can cause functional amblyopia.2 Till now no study has been done to evaluate the profile of the amblyopic children presenting to SCEH, Lahan. Materials and methods Informed consent was taken from the guardian of the patient before the enrollment in the study. This was a prospective, hospital-based observational study. Amblyopia was defined as 1) a decrease in best corrected visual acuity (BCVA) by 2 or more lines in either eye without any pathology of the visual system compared to good eye. 2) unilateral decrease of more than 1 line of BCVA in case of any amblyogenic factors.

Definitions used for the diagnosis of types of amblyopia were as follows 1) Deprivation amblyopia The light sense deprivation caused by the media opacities, complete ptosis etc can cause deprivation amblyopia. 2) Anisometropic amblyopia The difference of 1 D of hyperopia and 3 D of myopia causes anisometropic amblyopia. 3) Isoametropic amblyopia- This is caused due to the presence of high refractive error in both the eyes, resulting into an impaired form sense. It includes bilateral hyperopes in excess of 3 D and myopia in excess of 5 D.3 4) Strabismic amblyopia It is caused by the presence of any strabismus in distance or near fixation or both. Patients with strabismus and refractive errors less than 1D spherical error and 0.5D spherical equivalent were included in this group. 5) Refractive and strabismic amblyopia In this type of amblyopia, strabismus is associated with refractive component more than that of the true strabismic amblyopia. 6) Deprivation and refractive amblyopia It includes amblyopia associated both with deprivation and refractive causes either anisometropia or isoametropia. Page 20


Profile of Amblyopia - Joshi 7) Deprivation and strabismic amblyopia It includes amblyopia associated with both abnormal binocular interaction and light sense deprivation. 8) Mixed amblyopia All deprivation, refractive and strabismic factors are involved. (Note The classification system used may not be a standard one but the standard term `combined amblyopia is avoided for the aggregated type of amblyopia because the various amblyogenic factors must be studied separately so that the effect of each factor and its interaction with the other factors can be studied in greater detail and the effect of the type of factor in the prognosis is also very well known. Deprivation factor is difficult to treat than strabismic and strabismic is more difficult to treat than refractive.4) Visual acuity was taken with Snellens chart. History was taken about the age of first presentation, the cause of presentation and the duration of the defect noticed before the first presentation. Refraction was done objectively by retinoscopy and subjective refraction was performed whenever applicable. Results Demographic profile Sixty two percent (31) patients were from India. Fifty eight percent (29) were male and 42% (21) were female. Four percent (2) had family history of bilateral amblyopia and it was due to bilateral high myopia. Age distribution The mean age of the sample was 10.54 3.56 years. The mean age of the first presentation was 8.32 3.56 years and 42% (21) presented after 10 years of age. Maximum number of patients presented to the hospital with the complaints of whitish pupillary reflex and blurring of vision, 20% each (10 patients in each group). One child (2%) presented with developmental delay. Sixteen percent (8) patients were identified at the hospital as they presented with minor trauma to the eye, 7 of them with sub-conjunctival hemorrhage. Visual acuity and refractive error in amblyopic eyes Mean visual acuity in the amblyopic right eye was 0.146 (6/41) and left eye was 0.23 (6/26). Mean hyperopia was THE SIGHT, Vol. 5, Issue 5, September 2009 4.67 D and mean myopia was 17.8 D in right eye and it was 6.04 D of hyperopia and 9.5 D of myopia in left eye. Type of amblyopia The forms of amblyopia were: iso-hyperopic (38%), refractive and strabismic (22%), iso-myopic (10%), deprivation (3%), anisometropic (3%), deprivation and strabismic (3%). Study of 15 cases with manifest deviation Mean age was 10.06 years and 54% were female. The mean of the amplitude of strabismus was 19.6 degrees. Majority (66.1%, n=10) was associated with anisometropia, while 6.67% (1) with isoametropia, 13.3% (2) with deprivation and rest 13.3% (2) were associated with both deprivation and refractive. Only 20 % (3) complained of deviation and all of them were female. Among 15 cases, 13.3% (2) noticed reduced vision after trauma and same number noticed it by closing the normal eye. Exotropia was the commonest 73% (11) and rest 27% (4) had esotropia. Study of 10 cases with deprivation amblyopia Sixty percent (6) cases were female. 20% (2) cases had bilateral cataract surgery done with PCIOL at SCEH. Eight (80%) cases had previous history of unilateral cataract and operated with PCIOL. Five (50%) had refractive associations and 30% (3) had right exotropia. Mean visual acuity was .092 (6 /62.5) in the amblyopic eye. Mean error was 2 D spherical equivalent, (-6.25 to + 6.00 D). The mean age of presentation was 2.7 years with maximum of 12 years. Study of 5 cases with hyperopic anisometropia There were no cases of myopic anisometropia. The mean age of presentation was 8 years and the mean difference between the onset and presentation was 3.40 years. Four cases (80%) were referred from eye camps. Mean error was +6.95 D. Study of 24 cases of isoametropic amblyopia Mean hyperopic error was 7.22 D and mean myopic error was - 20.25 D in right eye. Mean hyperopic error was 7.15 D and mean myopic error was -14.75 D in left eye. Mean VA were 0.182 (6/33.3) and 0.26 (6/23) in RE and LE respectively. Page 21

Profile of Amblyopia - Joshi Discussions Unlike other studies done in India and Ethiopia, the commonest type of amblyopia in our subjects was ametropic amblyopia. The mean age of the sample studied was 10.54 3.56 years. The mean age of the first presentation was 8.32 years. The critical period of the human visual system is before 8 years. It shows that the subjects with amblyopia presented too late. And the age of presentation is higher in comparison to other studies. 5, 6 Hence we can see there is lack of awareness about childhood blindness from amblyopia. The presentation was 3.4 years after the problem had started. This also suggests that a child will have to live for 3.4 years to get to the hospital service after the problem is noticed by the family and hence this obstacle should be removed for effective management of amblyopia.

SCEH Age of 1st presentation Most common Ref error 8.32 3.56 Ametropic amblyopia Hyperopia (78%) Myopia 12%

India5 7.97 6.18 Strabismic amblyopia Hyperopia (51.65%) Myopia 33.95%

Ethiopia6 6.93 Strabismic amblyopia Hyperopia 61.71% 12% myopic

References1. 2. 3. 4. 5. 6. Duke Elder S. Ocular motility and strabismus, 1981; (6): 294-312 Noorden V. Binocular vision and ocular motility, 5th edition, Caloroso E. Clinical management of strabismus,3rd edition K. Nelson. Pediatric ophthalmology, 2nd edition Vimla Menon et al .Profile of amblyopia in a hospital referral., IJO 2005;53:227-234 Profile of amblyopia at the Pediatric Ophthalmology Clinic of Menilik II Hospital, Addis Ababa, Ethiop J Heath Dev 2008;22:201-205

Nabin Raj JoshiBachelor of Optometry, Final Year Institute Of Medicine Email: [email protected]


Page 22

Low Vision management in children- Khadka


REVIEW ARTICLE

A short perspective on Low vision aids for childrenJyoti Khadka, PhD Student The majority of low vision children can benefit from the use of low vision aids (LVAs). Researches have found that children prefer large print for convenience over LVAs, however it is important that they are encouraged to use LVAs as there will be situations where large prints are not available and those devices may be the only options, like in shops, at a friends house, science laboratory in school, reading comics and magazines etc. There are literally hundreds of LVAs available which include a range of items that are optical, non-optical and electronic devices. The use of these devices in combination with environmental modification can highly enhance visual function in children. This article briefly outlines the different low vision devices available. Optical Devices Optical devices or aids use lenses or prisms to magnify, reduce, or otherwise change the shape or location of an image on the eye's retina. The two most common optical devices are magnifiers for seeing objects close at an arm length (known as near viewing optical devices) and telescopes for seeing objects far away (known as distance viewing optical devices). Near-Vision Optical Devices Most children with low vision can significantly improve their vision at near by employing their strong ability to focus on nearby objects (accommodation) and brining the objects of interest closer to their eyes. But those who cannot see near objects well enough need some type of near vision optical devices. These are primarily used for tasks within arm's reach, such as reading, writing, drawing etc. Examples of some of these devices are discussed here. 1. Single Vision Spectacle Magnifiers Single vision spectacle magnifiers are spectacle frame THE SIGHT, Vol. 5, Issue 5, September 2009 mounted high power magnifiers. Children often favor these devices because they do not mind the close working distances needed and the devices give a luxury with both hands free. These magnifiers provide a large field of view, and prolong viewing time with reduced eye strain. The greatest disadvantage, however is that it involves a relatively short viewing distance, which usually causes head and neck fatigue after prolong use. a) Hand Held Magnifiers These are magnifiers mounted in plastic handles. They offer flexibility in magnification at various distances between the eye and the magnifiers. Hence children can choose the most suitable and comfortable viewing distance for their activities, depending on the size of the object or the text. In addition, the availability of strong magnification power and inbuilt illumination also make these magnifiers a good choice for those children who need above average illumination. The small size hand held magnifiers that fit in a pencil case or a pocket or on a string around the neck for having a quick look at very small printed information such as on a CD cover or measurement on test tubes are particularly popular among children and young people. However, use of hand held magnifiers require steady hands and good eye and hand co-ordination, which limit usefulness of these devices to very short period near viewing tasks only. These are not the devices of choice for those with upper limb disabilities. b) Stand Magnifiers Stand magnifiers are mounted to plastic stands with legs at a fixed distance from the reading material. The availability of options like inbuilt illumination and high magnification power make them very useful for those who have profound vision loss. Some designs are useful for writing also. However stand magnifiers are comparatively more expensive and bulkier than handPage 23

Low Vision management in children- Khadka held or single vision spectacle magnifiers and they also require smooth surface to rest on. c) Dome Magnifiers Dome magnifiers are especially designed stand magnifiers. These are slightly low power large field magnifiers which are also called bright field magnifiers, which allow longer working distance and are easy to use. d) Bar Magnifiers Bar magnifiers are also especially designed bar shaped stand magnifiers with limited magnification. These are available in low powers and good for prolong reading. Distance Viewing Optical Devices Optical devices for distance viewing are also known as telescopic devices. They include handheld monoculars, clip-on monoculars, spectacle-mounted telescopes, and binoculars. These devices are primarily used for distance tasks beyond arm's reach, such as reading what is on the chalk or white board in a classroom, watching a demonstration in class, spotting street signs, viewing sports events, or watching television. However, they are bulky and not suitable for navigation. OCUTECH Vision Enhancing System: The OCUTECH Vision Enhancing System is spectacle frame mounted manual or auto focus telescope system. This kind of device makes it easier for the visually impaired to see at distance like blackboard in school, signs while travelling and changes the focus either manually or automatically at near objects like books or computer screens. Besides being bulky, the OCUTECH system is available in low magnification only, is very costly and needs battery supply for auto focus design. Electronic Magnifiers There are also some electronic magnification systems that allow the user to aim a camera at an object in the distance and then view it on a screen. Most of these devices also allow the user to view near information THE SIGHT, Vol. 5, Issue 5, September 2009 similar to the way in which video magnifiers work. In the classroom, these devices allow a child to see what the teacher is writing on the white board and then to see the book he is working from or the notes he is taking. Electronic magnifiers like CCTV, portable video magnifiers, computer with magnifying software etc. are often better accepted by children and young people than magnifiers. Non-optical Devices and Environmental Modification Optical devices when incorporated with non-optical devices and environmental modification can help a child use his or her vision more efficiently. Non-optical devices include use of controlled lighting to improve contrast. Others are sunglasses, absorptive filters preferably with side shields, hats or visors with brims for outdoor activities, reading stands to improve poor posture caused by close viewing distance. Few nonoptical devices like dark-lined papers and black felttipped pens, which produce thicker lines, make childrens own writing easier to read. Environmental modification includes placing children near windows to give them better light when reading and near the white board, painting the edge of the stairs with bright colors and provision of hand rails in school for navigation. They should also be encouraged to wear hats and caps to prevent glare especially when doing outdoor activities. It is important to remember that low vision devices do not restore or give normal vision to low vision people. They do however help to maximize their use of vision to perform certain tasks. But, some children easily incorporate prescribed optical devices into their lives, while others refuse to use them sooner or later. It is important to encourage children to use them constantly at home, school and in the community. The earlier the child is prescribed these devices, the sooner they learn to use them, incorporate devices as a part of their life styles Page 24

Low Vision management in children- Khadka and pattern of learning. Especially older children may be self-conscious and dread being different from their peers. They must be advised to weigh their needs against the drawbacks of optical devices. When children come in contact with others who question the use of devices, they may feel self-conscious. It is recommended children should be taught to respond to such questions by explaining the reason for the devices and how they function. A need for peer acceptance and conformity, particularly during adolescence is a big issue to address in order to maximize the use of LVAs. On the other hand, children usually need to be re-assessed regularly as the things they want to do change and so the advice and devices they find useful will change too. Jyoti KhadkaPhD Student School of Optometry and vision sciences Cardiff University Email: [email protected]


Page 25

Comparison of Induced Astigmatism after cataract surgery - Kafle


ORIGINAL ARTICLE

Induced Astigmatism in Sutureless Small-Incision Cataract Surgery using a Superior and Temporal IncisionDinesh Kaphle BOptom., Albrecht Hennig MD, Rinki Singh MD.

Introduction: Small-incision cataract surgery (SICS) is one of the popular methods of operating cataract. Superior Incision SICS is easier and widely used technique as compared to temporal incision. Sagarmatha Choudhary Eye Hospital (SCEH), Lahan is one of the biggest eye hospitals in the world where thousands of people undergo cataract surgery each year. This study aims to compare the surgically induced astigmatism in SICS between superior and temporal approach Materials and Methods This is a comparative and analytical study and the patients with age related Cataract were selected randomly from the operation list for superior and temporal incision alternately. The patients with any preoperative pathology, complicated cataract or any known retinal pathology were excluded. Visual Acuity (VA) was taken with self-illuminated Snellens chart. Pre-operative and post-operative Keratometry was done with Hand-held Autorefractokeratometer-Nikon Retinomax. Biometry was done with Echo Scan Nidek (Model US 800). Postoperative VA and Keratometry were measured on the next day of the surgery. Astigmatism1 was recorded in minus sign considering 180 30 as with-the-rule (WTR), 90 30 as against-the-rule (ATR) and axis beyond these range as Oblique astigmatism. Induced astigmatism was calculated by taking difference between Post-op astigmatism and pre-op astigmatism. Frown Incision of 5-6mm was made with blade from 10 to 2 oclock and 2 to 5 oclock for superior and temporal incision group respectively. Sclerocorneal tunnel was made with crescent knife and keratome of 3.2 mm THE SIGHT, Vol. 5, Issue 5, September 2009

(superiorly and temporally). Endocapsular technique was used. Nuclear extraction was done with fishhook. PMMA lens of 5.5mm was inserted. Results: Out of 100 subjects, 50 (25 male and female each) underwent superior incision and 50 (26 male and 24 female) underwent temporal incision. Majority of cases were from 51-60 years age group in both the methods. In both groups more than 90% of patients were Functionally Blind2 before cataract surgery. Almost 80% gained normal VA after surgery. The visual outcome was slightly better in superior incision as compared to the temporal incision. Induced Astigmatism The induced astigmatism was much higher (almost five times) in superior group as compared to the temporal Induced Astigmatism Mean Induced Astigmatism (Dcyl) Mean Axis (deg.) group. Shift of Astigmatism Superior Incision 0.27 Temporal Incision 0.06

113.0

98.44

Page 26

Comparison of Induced Astigmatism after cataract surgery - Kafle Pre-operatively, majority of patients had oblique astigmatism and against-the-rule astigmatism in superior and temporal group respectively. Post-operatively, the shift of astigmatism was towards WTR in temporal group and towards ATR in superior group, whereas the number of patients with oblique astigmatism was decreased in both the groups. Two cases had no astigmatism on post-operative refraction on temporal incision group. Discussion: The mean induced astigmatism was 0.27 DC x 113 for superior group and 0.06 DC x 98 for temporal group. The amount of astigmatism found was less as compared to the study3 by Gorkhale Nikhil S. and Sawhney Saurabh. Still the pattern of induced astigmatism was same in both studies i.e. induced astigmatism less in temporal group than superior group. The post-op astigmatism was measured in the next day of the surgery as the follow-up rate of the patiens was poor. Induced astigmatism was calculated by simple method unlike vector analysis method used by Gorkhale Nikhil S. and Sawhney Saurabh because of the unavailability of proper resources for the analysis. There was shift of astigmatism towards ATR in superior group and towards the WTR in temporal group. This is similar to the findings of Goes F M Jr, and Goes F J study4 where they had analyzed the results by using Cravy-Jaffle-and Naeser-method.Pre-operative Astigmatism Post-operative Astigmatism

Type of Superior Temporal Superior Temporal astigmatism Incision (%) Incision (%) Incision (%) Incision (%) WTR (180 30) ATR (90 30) Oblique 10 (20) 6 (12) 11 (22) 12 (24)

12 (24)

25 (50)

18 (36)

23 (46)

28 (56)

19 (38)

21 (42)

14 (28)

Conclusion: Surgically induced astigmatism is lower in temporal incision as compared to superior incision. Postoperatively, the shift of astigmatism was towards WTR in temporal incision and towards ATR in superior incision. References:1. 2. Grosvenor Theodore, Primary Care Optometry, 3 rd ed., USA, Butterworth-Heinemann Khurana AK. Ophthalmology, 3rd ed. New Age Intrnl.;2003,p-424 (Category of Visual Impairment; WHO 1977) Gorkhale Nikhil S.,Sawhery Saurabh.Reduction in astigmatism in manual small incision cataract surgery through change of incision site. Journal of Gorkhale Eye Hospital and Eye Bank.2005;53(3) Goes FM Jr, Goes F J. Astigmatic changes after smallincision cataract surgery using superior or temporal corneal incision. Bull Soc Belge Ophthalmol. 1998;268:27-32

3.

4.

Dinesh Kaphle, B.Optom.Consultant Optometrist Visioncare, Blantyre Adventist Hospital, Blantyre, Malawi, Africa E-mail: [email protected]


Page 27

Pediatric Visual Impairment- Dev


REVIEW ARTICLE

Pediatric Visual ImpairmentMahesh Kumar DevIntroduction Visual impairment occurs when any part of the visual system is defective, diseased or malfunctioning. The primary causes of vision impairment in children are refractive error, congenital cataract, corneal scarring, congenital glaucoma, retinopathy of prematurity (ROP) etc. Corneal scarring due to Vitamin A deficiency, measles infection, ophthalmia neonatorum and the effect of harmful traditional medicine are the leading causes of blindness in the developing countries (Gilbert and Fester 2001). Other causes include albinism, optic atrophy, microphthalmos, aniridia etc. Prevalence and Magnitude Prevalence, magnitude and causes of blindness in children are largely determined by level of socioeconomic development and health care provision. Visual impairment in children is more common in poor countries due to inadequate eye care services. WHO estimates 1.4 million children are blind throughout the world, 1 million of whom live in Asia. The prevalence ranges from 0.3/1000 children aged 015 years in affluent countries to 1.5/1000 children in very poor communities. Every minute a child in the world goes blind (WHO-2006). Based on data from 2002 Survey of Income and Program Participation, 189,000 children of 6 -14 years of age have difficulty seeing words and letters in ordinary newspaper print even after wearing glasses or contact lens. Four percent of children under 14 years of age are blind worldwide (Thylefors et. al). Although the prevalence of visual impairment is relatively lower in children than in adults, the number of blind years (number blind length of life) in children is much greater than that in adults. They have a lifetime of blindness ahead, with an estimated 75 million blindyears. About 40% of the causes of childhood blindness are preventable or treatable. The control of childhood THE SIGHT, Vol. 5, Issue 5, September 2009 blindness is a priority of WHO/IAPB Vision 2020: The Right to Sight. Vision 2020 Priorities Corneal scarring due to Vitamin A deficiency, measles infection, ophthalmia neonatorum and the effect of harmful traditional eye medicines are given priorities in poor and very poor region. Refractive error: Treatable cause in all regions. Cataract and glaucoma: Important treatable causes in all regions. ROP: Preventable and treatable. It is important in middle income countries and urban centers in developing countries. Low Vision: Service need to be expanded or developed in all regions. Impact of Visual Impairment Visual impairment in childhood has an impact on the childs development, education and care given by families and professionals. These influence profoundly childs employment, social prospects and opportunities throughout the life. Impaired vision can affect a childs emotional, neurological and physical development by potentially limiting the range of experiences and the aids of information a child is exposed to. Nearly 2/3 of children with visual impairment have one or more developmental disabilities such as mental retardation, cerebral palsy, hearing impairment, epilepsy etc. So, children with vision impairment very often need services such as special education program to assist in their development. Role of Eye Care Professionals To provide specialist pediatric eye care, combining optical, medical and surgical management of specific disorders. To contribute to multidisciplinary visual impairment teams ideally combining medical, educational and social service professionals to Page 28

Pediatric Visual Impairment- Dev ensure comprehensive and coordinated care of all visually impaired children and their families. To contribute to specific assessment of special educational needs and certification of eligibility for special service. To contribute to monitoring visual impairment in geographically defined population they serve. as perinatal care. The current and future directions in research for diagnosing and treating pediatric vision disorders emphasize several areas. They include amblyopia, refractive screening, intraocular lens (IOL) implant, retinoblastoma, genetics including gene identification and mapping. Low vision due to congenital cataract is decreasing owing to decrease in incidence rate and increasingly successful use of IOL implant in younger children. The use of IOL in unilateral cataract decreases the severity of amblyopia. The advances in cytogenetics have greatly increased the ability to detect and potentially prevent genetic eye diseases. Genetic counseling also helps in decreasing the incidence of such diseases.

Conclusion Because of the wide range of causes of childhood blindness, intervention must be disease-specific and directed at more than one level of the eye-care delivery system. Preventive measures include the distribution of vitamin A capsules, immunization and prenatal as well References1. 2. 3. 4.

Taylor David, Hoyt S. Creig, editors. Pediatric Ophthalmology and Strabismus,3 rd edition. J Comm. Eye Health 2001; 14(40): 53-56 Silverstone Barbara, Lang A. Mary, Rosenthal P. Bruce, Faye E.Eleonar. The Lighthouse Handbook on Vision Impairment and Vision Rehabilitation, Volume1.Vision Rehabilitation Oxford University Press;2000. Gilbert C E, Foster A. Childhood blindness in the context of Vision 2020: The Right to Sight. Bull WHO 2001; 79:227-232.

Mahesh Kumar DevB. Optometry, IX Batch IOM, MaharajgunjEmail: [email protected]


Page 29

Progressive Addition Lenses - Paudel


REVIEW ARTICLE

Progressive addition lenses: What neophyte wearers and practitioners must know???Nabin Paudel, BOptomPresbyopia reflects a clinically significant loss of amplitude of accommodation, or an inability of eye to focus on objects at near. Presbyopia is a physiological condition and occurs after 40 years of age in most of the individuals. The exact mechanism of presbyopia is still under investigation but various researches have found that it is due to the aging process of lens capsule, tendons and ciliary muscles. The provision of extra plus power by external means is the only solution of this problem, which may be in the form of spectacles or contact lenses. Though, the practice of surgery for correction of presbyopia is also under investigation, spectacles are the best and the easiest method of correction of presbyopia. Presbyopic corrections in spectacles can be given in various ways. Single vision lenses: These glasses are worn only for near works and should be taken off otherwise. They allow clear vision only for near. Multifocal lenses: They incorporate power for near as well as distance and can be used all the time. They provide clear vision for near as well as distance. Progressive addition lenses: Progressive addition lenses (PALs) are the current state-of-art advances in multifocal lenses. PALs are especially designed lenses which incorporate correction for all distances ranging from distance to near. These lenses have a wide zone for distance in the upper part of the lens and a relatively wider near zone in the lower part of the lens which is connected by a narrow progressive zone. In the progressive zone the power gradually goes on increasing. So, these lenses are called progressive addition lenses. In the course of making a progression zone, on either side of the zone certain amount of astigmatism is produced which is practically unavoidable. Various researches have been done and are currently under investigation in order to minimize the THE SIGHT, Vol.5, Issue 5, September 2009 peripheral aberrations / astigmatisms so that they least interfere with useful field of vision. The schematic diagram of PAL is shown in figure 1. Progressive addition lenses have various advantages over single vision or bifocal spectacles. The absence of demarcation line between distance and near zone is the greatest advantage. PALs provide clear vision for all distances in contrast to single vision lenses and bifocal lenses. PALs dont cause image jump (areas appearing slanting and bumpy) while the eyes are shifted from distance to near or vice versa. However, PALs have certain disadvantages as well. They cause distortion of the peripheral vision, they are costly and they need certain time for adaption. However, the us

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