Eye Disorder..doc

Debre Brehan University, School of Health Science, Program of Nursing

Debre Brehan University, School of Health Science, Program of Nursing

Review of Anatomy & Physiology of the eye

The eye is the organ of vision which is located in a cone shaped cavity known as the orbit. It is highly specialized & complex structure. It receives & sends visual data to the cerebral cortex for interpreting visual images. Seven cranial nerves have connections to the eyes. These are;

For vision CN II. Eye movement CN III, IV & VI. Papillary reaction CN III. Eyelid elevation CN III. Eyelid closure CN VII. Brain stem connections permit coordinated eye movement. The eye ball is situated in the bony socket or orbit. The eye ball is protected by: - Orbit. Eyelids (Upper & lower). Nerves & blood vessels that supply nutrients & transmit impulses to the brain are also present with in the orbit. Organized bands of muscles are attached to the external eye ball. External Structures of the eye

Grey line; Where the skin joins palpebral conjunctivas. Glands: - Meibomian gland; It is found with in the tarsal plate, their ducts opening through the palpebral conjunctiva just behind the lashes. Produce sebaceous substance which creates the oily layer of the tear film.

Glands of moll These are sweat glands producing sebum. Muscles:-There are three muscles supplying the eyelid.

a. Orbicularis: Oculi

Origin: Lacrimal bone. Insertion:- Deep in the facia around the lacrimal. Function:- to close the eye lid & to screw up the eyes & facilitate tear drainage. Nerve supply:- Facial nerve (CN-VII). Its paralysis cause lag-ophthalmas (Failure to close eye). b. Levator palpebral superioris Origin: around apex of orbit. Insertion: skin of upper lid & tarsal plate. Function: to lift the upper lid. Nerve supply: Oculomotor (CN-III). Its paralysis cause ptosis (dropping of eye lid). c. Mullers muscle This is smooth muscle. Origin: Levator palpebral superiors. Insertion: Tarsal plate. Function: provide extra elevation to the upper lid. Nerve supply: Sympathetic nervous system.

The junction of the upper & lower eyelid is called canthus/commisure. The outer, Lateral Canthus is on the lateral temporal aspect of the eye. The inner, Medial Canthus contains the Puncta, openings that allow tears to drain into the upper portion of the lacrimal system. The elliptical space between open eye lid is called palpebral fissure. Vertical palpebral fissure = 8-11mm (More wide in female). Horizontal palpebral fissure = 27 30 mm.

Upper eye lid is more mobile than lower eyelid. Skin It is the thinnest of the body. It is freely movable. Meibomian gland orifice in a single row. The anterior border of lid margin gives rise to the eye lashes. Eye lashes:-hairs-like filament (cilia) 2 to 3 irregular row. With 100 lashes on upper lid. With 50 lashes on lower lid (thin & short). It is important to trap dust particles. Subcutaneous connective tissue Loose & doesnt contain fat. This cause rapid accumulation of fluid (Oedema)

Tarsus It is called skeleton of the eyelid. Conjunctiva It is a mucous membrane. Its zones are: - Palpebral conjunctiva: forms inner layer of eyelid & reflects over eye ball. Bulbar conjunctiva; It is extremely thin & transparent so that vessels are easily seen.

It is freely movable. Covers the eye ball except the cornea. Fornices: formed where bulbar & palpebral conjunctiva fold back over each other. Eyelids; It is skin without subcutaneous fat. It has 4 basic layers. From anterior to posterior the layers are; Skin & subcutaneous connective tissue. Muscle. Tarsus . Conjunctiva.

Functions of eye lids; Protect eye ball (globe). Lubricate anterior surface of globe (By blinking the tear film spread over anterior surface). Blood supply to the lid; Lacrimal artery & vein. Supra orbital artery & vein (upper lid). Superior & inferior medial palpebral artery & vein. Lacrimal glands & Excretory System Lacrimal glands Location Superiorly in a shallow depression of frontal bone.

It has 2 parts: -

Orbital (lacrimal gland proper). Numerous Excretory ducts emptying secretion to conjunctiva. Mechanism of tear secretion is by: -

Reflex due to stimulation of trigeminal nerve. Psychogenic central mechanism.

Accessory glands Krauses gland located in the eye lid. Meibomian gland Basal tear secretion is constant & under sympathetic nervous system control.

Function of tear

Refraction: to provide an optically smooth surface to the cornea. Lubrication of the front of eye ball. Cleansing action by washing away dust particles from the eye. Protection from infection by secreting the enzyme lysozyme, immuno-proteins & antimicrobial agents. Flow of tear is affected by; Blinking. Capillary attraction into the puncta. Lacrimal pump by contraction of muscle. Gravity. Internal Structure of eye

Eye Ball; It is lined by 3 layers, 1. Outer protective layer It is fibrous layer. It consists; A. Sclera It is the white part of the eye. Form outermost tissue of posterior & lateral (4/5)th aspects of eye ball. It is continuous anteriorly with cornea. Maintains the shape of the eye & gives attachment to extra ocular muscle of eye. B. Cornea It is the anterior continuation of sclera. It is clear transparent & allow passage of light rays. It is convex anteriorly & is involved in refraction or bending light rays to focus them on retina. It is highly sensitive. 2. Middle layer It is Vascular organ. It Consists; A. Choroid Lines the posterior (5/6)th of inner surface of sclera. Highly vascularized. Light enters the eye through the pupil, stimulate the nerve endings in the retina then is absorbed by the choroid. Deep chocolate brown in colour. B. Ciliary body It is anterior continuation of the choroid & consists ciliary muscle & secretary cells (producing aqueous humor). It gives attachment to suspensary ligament which, at its other end, is attached to the lens. The ciliary muscle controls the shape of lens for focusing. C. Iris It is the visible coloured part of the eye & extends anteriorly from the ciliary body, lying behind the cornea in front of the lens. It divides the anterior segment of the eye into anterior & posterior chambers which contain aqueous fluid secreted by ciliary body. In the center is an aperture, the pupil. The pupil varies in size depending upon the intensity of light. During bright light the pupil constrict, whereas dilate during dim light . D. Lens It is a highly elastic circular biconvex transparent body, lying immediately behind the pupil. It is suspended from the ciliary body by the suspensory ligament & enclosed with in a transparent capsule. Its thickness is controlled by the ciliary muscle through suspensary ligament. It bends light rays reflected by an object in front of eye. 3. Inner layerA. Retina It is nervous tissue layer. Retina is especially adapted to be stimulated by light rays. Composed of several layers of nerve cell bodies. Rods & cones are layer highly sensitive to light. Macula It is an area of the retina situated to the temporal side of the optic disc. It contains a high concentration of cones. In its centre is the fovea centralis, a slight depression where only cones are present. B. Optic disc Contains no nerve cells, so the vision cannot take place here. This is known as the blind spot. Structures inside the eye ball are Aqueous humour (fluid). Vitreous body. The anterior segment of the eye, i.e. the space between the cornea & the Lens, is incompletely divided into anterior & posterior chambers by iris. Both chambers contain a clear aqueous fluid. Aqueous fluid It is secreted by ciliary gland. It passes in front of the lens, through the pupil into anterior chamber & returns to the venous circulation in the angle between iris & cornea. Produced continuously & drained but the IOP remains fairly constant b/n 10 to 20 mm hg. An increase in pressure cause glaucoma. Vitreous body It is found behind the lens & filling the cavity of the eye ball. Soft, colourless, transparent, jelly like substance composed of 99% water. It maintains sufficient IOP to support the retina against the choroids & prevent the wall of eye ball from collapsing. The eye keeps its shape because of IOP exerted by vitreous & aqueous fluid. Optic nerves The fibers of optic nerve originate in the retina of the eye. All the fibers converge to form the optic nerve about 0.5cm to the nasal side. It pierces the choroid & sclera to pass backwards & medially through the orbital cavity. Passes through optic foramen of sphenoid bone, backwards & medially to meet the nerve from the other eye at the optic chiasma. Optic chiasma It is situated immediately in front of & above the pituitary gland in the sphenoid bone. In the optic chiasma the nerve fibers of the optic nerve from the nasal side of each retina cross over to the opposite side. The fibers from temporal side do not cross. Physiology of Sight Light reflects into the eyes by objects within the field of vision. A specific colour is perceived when only one wave length is reflected by the object & all the others are absorbed. E.g. an object appears red when only the red wave length is reflected. Objects appear white when all wavelengths are reflected & black when they are all absorbed. In order to achieve clear vision light reflected from objects with in the visual field is focused on the retina of both eyes. The processes involved in producing a clear image are refraction of the light rays, changing the size of pupils & accommodation of the eyes. Refraction of the light rays

When light rays pass from a medium of one density to a medium of a different density they are refracted or bent. Helps to focus light on retina. Lens: - is the only structure in the eye that changes its refractive power. Light from distant objects needs least refraction & as the objects come closer, the amount needed is increased (i.e. ciliary muscle contract).

Size of the pupils: - control the amount of light entering to the eye. If the pupils were dilated in a bright right, too much light would enter eye & damage retina. The two muscles of iris, circular muscle fiber constriction causes pupil to constrict but constriction of radiating muscle fiber dilate pupil. Accommodation of the eyes to light Close Vision In order to focus on near object i.e. with in 6 meters, the eye must make the following adjustments. Constriction of the pupils. Convergence of the eye balls (Movement). If convergence is not complete there is double vision (diplopia). Changing the power of lens the lens is thicker. Distant Vision Objects more than 6 meters away from the eyes are focused on the retina without adjustment of the lens or convergence of the eyes. With aging, the ability of the eye to accommodate gradually decreases because of increased rigidity of the lens (Presbyopia). The lens is tense able to change shape in response to visual challenge of focusing on near objects. Summary of eye structure

Passage way of light raysLight Cornea Pupil Iris Lense

AH VH Retina Optic Nerve

Cerebral Cortex.

1. Assisting the patient in measurement of visual acuity The measurement of visual acuity records the acuteness of central vision for distance, and near or reading vision. Visual acuity: - is the most important function of eye and it should be performed first, so that vision is assessed before actually touching the eye. Distance Vision It is tested at 6m as rays of light from this distance are nearly parallel. If the patient wears glasses constantly, vision may be recorded with & without glasses, but this must be noted on the record. Each eye is tested and recorded separately, the other being covered with a card held by the examiner. Visual acuity is tested with an eye chart called snellens chart. Snellens Chart test type Heavy black letters, numbers or symbols printed in black on a white background, are arranged on a chart in grows of graded size, diminishing from above downwards. The top letter can be read by the normal eye at a distance of 60m, and the following rows should be read at 36, 24, 18, 12, 9, 6, 5, 4m respectively. The patient is seated 6m from the chart, which must be adequately lit, & asked to read down to the smallest letter he can distinguish, using one eye at a time. Visual acuity is expressed as a fraction & abbreviated as VA. The numerator is the distance in meters at which a person (pt)can read a given line of letters. The denominator is the distance at which a person with a normal average vision can read the same line. Example: - If the 7th line is read at a distance of 6m this is VA 6/6. If same letters in the line are read but not all, it is expressed as, for example, VA 6/6 -2, or VA 6/9+2. For vision less than 6/60 the distance between the patient & the chart is reduced a meter at a time & the vision is recorded accordingly as, for example, 5/60, 4/60, 2/60, 1/60. If the patient cannot read the top letter at a distance of 1 meter, the examiners hand is held at 0.9m, 0.6m or 0.3m a way against a dark background & the patient is asked to count the number of fingers held up. If he answers correctly, record VA= CF (Count Fingers). For less visions the hand is moved in front of the eye at 0.3m, record VA = HM (Hand movement). In the case of less vision, test for projection of light by shining a torch into the eye from different directions to see if the patient can tell from which direction it comes if he sees the light from which direction, it is noted as VA = PL(Perception of light). This test is performed in the dark room. If no light is seen, record NO PL, which is total blindness. A pinhole disk is used if the VA is less than 6/6, which may improve VA. If considerable increase in vision is obtained, it may usually be assumed that there is no gross abnormality, but a refractive error. 2. Assisting on ophthalmoscope Examination The internal eye is called the fundus & comprises the retina, optic disc, macula, & retinal vessels. It can be visualized through an ophthalmoscope. Def: - Ophthalmoscope is a hand-held instrument that projects light through a prism & bends the light at 90 degrees, allowing the observer to view the retina. The direct ophthalmoscope has several lenses arranged on a wheel. A lens may be chosen by rotating the wheel with the index finger with out interrupting the inspection. To a void a confrontation of noses, the right eye of the patient is examined with the right eye of examiner The room is darkened to enhance papillary dilation. Instruct the patient to hold the eyes still & focus on a real or imagined distant object. Grip the ophthalmoscope firmly in the hand, with the index finger resting on the lens wheel. The head of the ophthalmoscope is braced with in the angle made by the eye brow & the nose. The lens chosen for initial inspection should be the one labelled zero unless the examiner is knowingly correcting his own defect in visual a acuity. An examiner who wears corrective lenses should become proficient in ophthalmoscopy while wearing the lens. Lenses lobe led with a red numerals are for hyperopic (far sighted) patients & those with a black numerals are for myopic (nearsighted) patients. The examiner stands approximately 37.5cm away & about 15 degrees to the side of the patients gaze. When the light is focused on the pupil, the retina glows red (or orange) through dilated pupil opening. This is called the red reflex. The examiner then moves closer to the patient. Placing a hand on the patients forehead, the examiner rests his or her forehead on the hand & focuses through the ophthalmoscope. Examining the fundus includes evaluating: - The optic disc Retinal blood vessels Retinal characteristics Macular area Vitreous hum The disc for: -

Its physiologic cup & Proportional size The blood vessels for:- Size

Distribution

Crossings & colour reflection Retinal fundus for: -

General Colour

Hemorrhagic

Fluid

Attachment

Macula & fovea centralis for: -

Colour (darker red)

Central reflection

The vitreous humor for: -

Colour

Foreign bodies

3. Assisting in measurements of intraocular pressure

Tonometry is a technique for measuring intra-ocular pressure (IOP) indirectly by measuring the force necessary to flatten a 3.06mm diameter portion of the corneal surface. The higher the IOP, the greater the force required. Methods of measuring IOP:- Digital. Golmann applanation tonometer. Schiotz (perkins applanation) tonometer. Pneumotonometer. Tonopen. Schiotz tonometry Requires using a metal, hand held instrument (the tormenter) that rest on the anesthetized cornea. The result can be variable but are a good estimate of IOP.

Goldmann applanation tonometry it is attached to a slit lamp to measure IOP. It is the most accurate form of measuring IOP.

Procedure

Identity the patient.

Check if the patient is wearing contact lenses, if so then remove them before commencing the procedure. Administer topical anaesthesia into both eyes.

Instil fluorescein stain for accurate reading.

Instruct the patient to look straight a head with both eyes wide open- if necessary, the patients eyelids should be held apart by the examiner with out pressure being applied to the eyeball.

The ton meter is brought into contact with the center of the cornea .

The IOP (in mm Hg) is found by multiplying the drum reading by ten.

Non contact tonometer (pneumotonometer) It is employed by optometrists, use a puff of air blown against the eye. It is useful when contact with the cornea is not desired. Digital A general determination of IOP can be made by applying gentle finger pressure over the sclera of the closed eye. The tips of both fore fingers are placed on the closed upper lid. One finger gently presses inward while the adjacent finger senses the amount of pressure exerted against it. The examiners then compare the tension felt or perceived in the patients eye with the pressure in their own. This requires practice.

The patient looks down wards, closing the eye.

palpate the eye ball to assess the degree of hardness. No accurate measurement can be taken but on eye with raised pressure will feel harder than one with normal pressure. It is a useful initial method of assessment, especially if none of the specialized equipment needed for measuring IOP is available.

Tonopen Are small pen like instruments that measure pressure in a similar fashion to the applanation method.

NB: - IOP = normal value is 10-20mmHg. Increased IOP is the cardinal sign of glaucoma 4. Assisting the patient in measurement of refractive errors

Refraction

Determination of refractive errors.

Corneal Reflections

Method: - A pen torch is held at 1/3m directly in front of both eyes. The position of the reflection on each eye is then compared.

Results: - The results may be: -

Normal Corneal reflections symmetrical.

Asymmetrical Corneal reflections.

Cover Test:-It is carried out to detect the presence of a squint, & should be used in conjunction with observation of the corneal reflections.

Method: - A penlight is held at ~ 1/3m from the child. The child must be looking at the height whilst the cover test is carried out. It is important to repeat the cover test using a detailed target, e.g. a small picture on a tongue depressor, because same squints are only present when looking at detailed objects. The caver test should also be carried out at 6m where possible because other squints are only present when looking into the distance, i.e. intermittent squints. Cover one eye, watch for any movement of the uncovered eye, remove the cover & repeat covering the other eye & watching for any movement of uncovered eye.

The results may be: -

No manifest squint.

Manifest squint right convergent squint (Fig 13.6)

Manifest squint right divergent squint (Fig 13.7) Ocular Movements

The examiner sits in front of the patient & using a pen torch, observes both eyes moving in all eight positions of gaze.

This will include up, down, both sides & in all four corners, always returning to the straight a head or primary position. The patients head must be held still. Any muscle imbalance, over action & under actions are then noted. Refractive errors RE is a pathological condition where parallel rays of light are not brought to focus on retina, b/c of defect in the refractive media that is cornea and lens. Refraction is the ability of the eye to bend light rays, so that they fall on the retina. In normal eye, parallel light rays are focused through the lens in to a sharp image on retina, this condition termed as Emmetropia. Emmetropia means the light is exactly focused on the retina, not infront of it or behind it. When the light is does not focus properly, it is called a refractive error. Refractive errors include; 1. Myopia (Short sightedness). 2. Hyperopia or hypermetropia (Long sightedness).3. Astigmatism (asymmetric focus).4. Presbyopia.5. Aphakia. 1. Myopia or short sightedness

A short sighted person has a long eyeball and the eye have excessive refracting power (cornea and lens). The light rays therefore come to a focus in front of the retina. Can see near objects clearly. Objects at a distance are blurred. C/F = decreased distant vision. Can be corrected by concave lens (minus), so that objects seen in the distance are focused clearly on the retina. It bends light ray out ward.

2. Hyperopia or long sightedness

The eye has insufficient refractive power to focus light on the retina. The rays of light entering the eye are focused behind the retina. The individual can see distant object clearly, but close objects are blurred (C/M-Impairment of near vision). Can be corrected by convex lens (plus) which bends light ray inward.

3. Astigmatism

It is a refractive error in which the light rays are spread over a diffuse area rather than sharply focused on the retina. It results from unequal curvature of the cornea, causing horizontal and vertical rays to be focused at two d/t pts on the retina, so that there is no point of focus of the light rays on the retina. C/F: - blurred vision, eye discomfort. It can be hyperopic or myopic in relation to where the image falls. 4. Presbyopia

It is a form of hyperopia that occurs as a normal process of aging usually around the age of about 45 years. As the lens ages and becomes less elastic , it loses its refractive power and the eye no longer has the ability to accommodate for near vision. The light rays therefore fall behind the retina before coming to a focus. Can be corrected by convex lens. 5. Aphakia

It is the absence of crystalline lens. The lens may be absent congenitally, cataract surgery, trauma. Eye loses about 30% of its refractive power and no near vision. Can be corrected by implanting intraocular lens.External Ocular diseases1. Hordeolum (Sty)

A Sty is an acute suppurative infection of superficial eye lid sebaceous glands. Cause: - Staphylococcus aureus. C/F: - Sub acute pain, redness, & swelling (edematous) of a localized area of the lid that may rapture. - Stys are localized to the lid margins. - small collection of pus in the form of an abscess.

Mx Worm, moist compresses for 10 to 15 minutes, three to four times a day, hastens the healing process. If the condition doesn't begin to resolve with in 48 hours, incision & drainage may be indicated. Application of topical antibiotics. Analgesics. 2. Chalazion

Defn: - Chalazion is a swelling of one of the meibomian/tarsal glands due to blockage of its duct. It is chronic condition. It is some times called internal hordeolum. Cause: - Staphylococci are common causes if infected. C/F: -Localized, firm, painless swelling that develops over period of weeks. -Palpation usually indicates small, painless nodule in the eye lid some distance from the lid margin. Mx Worm, moist compresses for 10 to 15 minutes, three to four times a day especially in the early stage. Massage & expression of the glandular secretions. Antibiotic therapy (Chloramphenicol;- apply 3-4 x/d for 7-10 day, after the eye has been steamed). Corticosteroid drops/injection in to the chalazion lesion. Incision is indicated if the chalazion grows larger enough to distort vision. Nursing Care: Instruct the patient to apply steam to the eye. Instruct how to use drugs. Instruct the pt. to clean eye lids by using worm water. 3. Blepharitis

It can be a cute or chronic inflammation of both eyelid margins. It is usually bilateral. It can take the form of;1. Staphylococcal blepharitis:- It is usually ulcerative and more serous due to involvement of the base of hair follicle. Permanent scaring can result. Caused by staphylococcal chronic infection. 2. Seborrehic blepharitis:- It is chronic and usually resistant to Rx, but the milder case can respond to lid hygiene. Caused by Seborrhoea (excessive secretion of lipid from meibomian glands). It may be associated with dandruff, poor hygiene, eczema. C/M Irritation of eye lids margins and red rimmed eyes with many scales or crusts on the lid margin and eye lashes. Burning. Itching. Photophobia. Conjunctivitis may occur simultaneously. Mx Daily meticulous cleaning of the lid margins using cotton tipped applicator, with dilute baby shampoo: 2x/day. Worm Compresses. Application of antibiotic ointment 2-3x/d. Dandruff RX. Stop using make up or change the brand used. Improve hygiene. Complication Conjunctivitis. Trichiasis. Entropion or ectropion of lower lid. Corneal Ulcer. 4. Trichiasis

It is a condition in which the eye lashes grow in words & rub on the cornea. Cause: - blepheritis - Trauma or surgery to the lids. Rx: - Epilation Complication: - Corneal abrasions - Corneal ulceration - Corneal Opacity - Vascularisation of cornea 5. Entropion Turing inward of eyelids, usually lower eye lids.

Cause: - Contraction of the palpebral conjunctiva following trauma or disease to the eye lid or conjunctiva.

Rx: - Transverse lid surgery and suture.

6. Ectropion

It is turning outwards of the eye lids, usually the lower lids.

Cause: - Scaring of the lid or conjunctiva - Paralysis of facial nerve. Rx:- Surgery 7. Ptosis

It is dropping of the upper eyelid. Cause: - congenital. - Oedema, tumor & scarring of eye lid - Myasthenia gravis (Levator palpebral superioris). - Paralysis of nerves supplying the upper lid. Rx: - Treat underlying cause. Disease of conjunctiva1. Conjunctivitis

Conjunctivitis an inflammation of the conjunctiva. It is the most common ocular disease world wide. It is characterized by a pink appearance (hence the common term pink eye) b/c of subcutaneous blood vessel haemorrhages. Cause1. Infections;1. Bacteria (Haemophilus influenza, staph aureus).2. Virus (Adeno virus, HSV).3. Chlamydial.4. Fungal.5. Parasitic.2. Immunologic (allergy); environmental allergens (e.g. pollens).3. Irritant/toxic (Chemical, thermal, electrical).4. Associated with systemic disorder. Most conjunctivitis is bilateral; unilateral involvement suggests a toxic or chemical origin. 1.1. Bacterial Conjunctivitis

It can be acute or chronic Causative agents: - Streptococcus - Staph. auerus - Pneumococcus C/M Conjunctival injection, especially in the fornices where the blood supply is rich. Hyperemia/redness. Purulent discharge. Pain. Rx & Nursing Care Take swab from affected eye for culture & sensitivity if severe. Clean the eye using cooled, boiled water. Chloramphenicol or tetracycline eye drop or paint 3x/d for 3-5days.1.2. Neonatal Conjunctivitis

Severe conjunctivitis occurring in a baby less than 28 days old is notifiable disease.Cause: - Gonococcus - Streptococcus - ChlamydiaC/M: - Severe discharge - Red, swollen eye lids - Chemosis (edema of the conjunctiva) - Unilateral or bilateral infection.

Rx: - Clean the eye. - Gentamycin eye drop TID. - Oral antibiotics. Complication: - Conjunctival Scarring. - Chronic blepheritis. - Conjunctival ulceration & perforation. - Marginal corneal ulcer.1.3. Viral Conjunctivitis

Cause: - Measles

- Herpes Simplex

- Varicella

C/M Red eye.

Chemosis, if severe.

Follicle may be present on the palpebral conjunctiva.

Keratitis .

Watery discharge & photophobia.

Rx: - Self limiting (with in 7-10days).

- Steroid Rx.

Mx summary for bacterial and viral conjunctivitis (highly contagious) Hand washing. Avoid sharing hand towels, face clothes, eye, drops. Tissue paper should be directly discarded in to a trash can after use. Using new tissue paper every time you wipe the discharge. All forms of tonometry must be avoided unless medically indicated. 1.3. Allergic Conjunctivitis

Causes: - Hay fever, EczemaC/F: - Severe chemosis - Red eye - Watery eye - Sinusitis may present - Burning sensation & severe itching - Photophobia Rx: - Betamethasone or hydrocortisone drop. -Wearing dark glass.

2. Trachoma

Trachoma is a highly contagious infectious eye disease (Chlamydia Conjunctivitis) that affects more than 500 million people world wide and which may result in blindness.

It is the world's leading cause of preventable blindness & primarily affects people in Africa.

Pathophysiology Scaring of the inside of the eye lid. The eye lid turned inward and the lash rubs the eye ball. Scaring of the cornea. Irreversible corneal opacities and blindness.Cause: - Chlamydia trachomatis

Mode of transmission:-

Direct Contact (with eye, nose, throat secretion from the affected individual.

Fomites (towel, hand kerchiefs, fingers, wash clothes).

Insect Vector (flies).

C/M Mild itching & irritation is principal symptom. Red eye. Discharge (slightly purulent). Follicles & papillae an upper palpebral connective. Keratitis. Entropion and trichiasis of the upper eyelid. Chemosis of bulbar conjunctiva. Blurring of vision. Photophobia. Pannus blood vessels on the upper part of cornea. Corneal scaring.Complications Scarring of eye lids.

Entropion.

Trichiasis.

Corneal trauma & ulceration.

Mx: - Good personal hygiene

- Tetracycline eye

ManagementSAFE strategy;

Surgery:- trichiasis and entropion.

Antibiotic:- TTC (ointment apply TID for 3-4weeks.), sulphonamides, erythromycin.

Facial cleanness:- good hand and face washing practice.

Environmental changes:-address water shortage, eradicate flies, avoid crowded, e.t.c.

Disease of cornea1. Keratitis

Keratitis is an inflammation of the cornea.

Cornea is susceptible to infection and injury because of its anterior location and degree of exposure.

Cause Exposure (exophtalmos, lagophtalmos) keratitis as a result of drying of the cornea because of eye lids can not protect it adequately. Infections; Bacteria (staph.. aureus, strep.. pneumonia, pseudomonas aergunosa).

Virus (herpes simplex, varicella zoster virus).

Fungus (Candidia, aspergillus, cephalosporium).

Parasitic organism.

Most of infections of cornea occur as a result of trauma or compromised systemic or local defense mechanism.C/M Sensation of foreign baby in the eye. Marked inflammation of glade (open space). Muco-purulent discharge with the eyelids stuck together on awakening. Ulceration. Hypoyon (Pus in the anterior chamber). Photophobia. Blurred vision. In advanced disease; Perforation of cornea. Extrusion of the iris. End-ophthalmitis.Dx Identifying the ulcer by slit - lamp examination after instilling fluorescein drops to demonstrate the shape & size of the ulcer under special light.Mgx Patients with severe corneal infections are usually hospitalized to allow frequent administration (every 30 minutes) of antimicrobial drops & regular examination. Keep the lid clean.

Cool compresses.

Monitor for sign of increased IOP.

Acetaminophen 500mg 2tabs PRN.

Cycloplegic & mydriatics to relieve pain & inflammation.

Complication

Corneal Scar.

Revascularization (new blood vessels formation) in the cornea.

2. Pterygium

Pterygium is a triangular fibro-vascular connective tissue over the growth of the intra-palpebral conjunctiva with extension to the cornea.

Usually occurring on the nasal side, but it can be temporal.

It is thought to be an irritative and degenerative phenomenon caused by ultraviolet light.

Cause unknown.

Predisposing factors: - people who live in hot, dry climates or who work in the open air.

Rx Surgical removal if pterygium encroaches on the visual axis or causes significant discomfort.

In 30-50% of cases it reoccurs after surgery.

3. Corneal ulcer

It is ulceration of cornea.

Etiology Bacteria;

Staph.. aureus, strep.. pneumonia, pseudomonas aergunosa.

Fungus

Candidia, aspergillus. C/M Pain. Blurred vision. Photophobia. The ciliary vessel around the cornea will be dilated.Dx Hx. P/E. Culture and sensitivity. Microscopic exam. Mgx Treat urgently. Antibacterial; Gentamycin and ciprofloxacilin eye drops. Antifungal; Natamycin and econazole eye drops.Intraocular disease /disorder of the Lens/1. Cataract

It is clouding or opacity of crystalline lens the impairs vision.

The lens is a delicate structure & any insult on it causes absorption of water, resulting in the lens becoming opaque.

According to WHO, cataract is the leading cause of blindness in the world (2002).

Cause

From birth (congenital).

Age (senile).

Eye injury (traumatic).

Secondary to existing eye disease (e.g. uveitis).

Drug like corticosteroids.

Cataract associated with systemic disease (DM, Hyperparathyroidism).

UV light exposure.

High dose of radiation therapy.

Degree of Cataract Immature cataract part of the lens is opaque.

Mature cataract the whole lens is opaque & may be swollen.

Congenital Cataract

Cause

Abnormal development of the eye.

Metabolic disturbance.

Rubella or malnutrition in first trimester of pregnancy.

C/M Unable to see.

white pupil (Unilateral or bilateral).

Rx: - Removing the cataract

Senile Cataract

Occur in patients over the age of 60 years.

They result from sclerosis of the lens due to a degenerative process.

Usually bilateral.

It is either;

Nuclear:-

affects the central lens & takes on a brown color.

The patient sees better in dim light when pupil is dilated.

Cortical:-

Affects the periphery of the lens & looks white.

Vision is usually better in bright light when the pupil is constricts.

General C/M Gradual, progressive, and painless loss of vision.

Double vision/blurred vision/

Reduced light transmission.

Rainbow/haloes/

Previous dark pupil appear milky or white.

Dx Hx.

P/E.

Ophtalmoscopic exam.

Slit lamp examination.

Mgx Surgery; surgical removal of the lens usually done under local anesthesia.

IOL (intraocular lens) are usually implanted at the time of cataract extraction.

Nursing intervention Preparing the pt for surgery. Orient pt and explain the procedure and plan of care to decrease anxiety.

Instruct the pt not to touch to decrease contamination.

Administer preoperative eye drops.

Postoperative care; Administer medication as prescribed.

Teach the pt to report sudden pain and restlessness with increased pulse.

Caution pt against coughing, sneezing, rapid movement, bending.

Encourage pt to wear shield at night to protect operated eye fro injury while sleeping.

Diseases of sclera1. Scleritis

It is an inflammation and swelling of sclera.

Etiology

Associated with connective tissue disorder like rheumatoid arthritis.

C/M Severe pain. The white part of the eye may appear red, swollen and a nodule which is painful in touch.Mgx Heavy immune suppression. Systemic corticosteroid and eye drops. Systemic NSAIDs and treating the underlying cause.Disease of uveal tract1. Unveitis

Uveal tract comprises the middle vascular pigmented layer of the eye.

It is composed of three areas: -

The choroid.

The ciliary body.

The iris.

Def: - Uveitis is the inflammation of one or all structures of the uveal tract.

Because the uvea contains many of the blood vessels that nourish the eye and because it borders many other parts of the eye, inflammation of this layer may threaten vision. Cause

Bacteria ( TB).

Virus (CMV, syphilis, herpes zoster and simplex).

Fungi (toxoplasmosis, histoplasmosis, ocular candidiasis).

Chemical

Trauma

Allergy

1) Acute anterior uveitis (iritis) Is the most common type.

Is characterized by a history of pain, photophobia, blurring of vision, & red eye.

Rx Dilating drops (mydriasis) are instituted immediately to prevent scar formation & adhesion to the lens (Synechiae), which may cause glaucoma by impending aqueous outflow.

Local corticosteroids are used to decrease the inflammation.

Wearing sunglasses.

Analgesics.

2) Intermediate uveitis (Chronic cyclitis) It is characterized by Floating spots in the field of vision.

Rx: - Topical or injectable corticosteroids are used in severe cases.

3) Posterior uveitis (Inflammation affecting the choroid or retina) Is usually associated with some form of systemic disease, such as AIDS, herpes simplex or zoster, tuberculosis.

C/M Decreased or distorted vision.

eye redness & pain.

Rx Systemic corticosteroid.

Uveitis generally categorized into two. These are;

1. Non-granulomatous

2. Granulomatous

C/M for NGU; Have acute onset. Pain. Photophobia. Conjectival ejection (congestion of blood vessel), especially around the cornea. Pupil will be small or irregular. Vision will be blurred. Hypopyon in severe case. Anterior synechia (peripheral iris adheres to cornea and impeds out flow of aqueshumour). Posterior synechia (adherence of the iris and lens). C/M for GU; Insidious onset. Vision is markedly and adversely affected. Conjuctival injection is diffuse. Vitreous clouding. Photophobia pain is minimal.2. Sympathetic Ophthalmia

It is a rare but devastating bilateral uveitis .

Occurs after a latent period of days to years after a penetrating injury to the uveal tract.

Cause Unknown

Predisposing factor: - Allergy

C/M Inflammation of injured eye, followed by inflammation of the unaffected (Sympathetic) eye.

MX Enucleation of the sightless eye within 10 days of injury is usually recommended to reduce the risk of sympathetic disease in the other eye.

Indication for enucleation

Blindness after penetrating injury.

Painful blind eyes that is unresponsive to the medical treatment.

Tumor of the eye.

Disease of the inner ear1. Panophthalmitis

It is an inflammation of all tissue of the eye ball.

Etiology

Bacteria.

Virus.

Fungus.

E.t.c

Hx of recent intraocular operation.

Penetrating trauma.

Common in immune compromised pts, such as HIV/AIDS and diabetes.

C/M Severe pain. Loss of vision. Redness of conjunctiva and underlying episclera.Mgx Medication (antimicrobial plus steroids) Topical. Subconjuctival. Intravitreally. Systemically, or in combination form. Surgery Enucleation.Injuries to the eye1. Trauma to the eye

A. Blunt contusion It is bruising of the periorbital soft tissue.

C/M Swelling and discoloration of the tissue.

Bleeding in to the tissue and structure of the eye.

Pain.

Mgx Reducing swelling and pain by applying cold and warm compress.

Refer for ophthalmologist asst.

B. Hyphema It is the presence of blood in the anterior chamber.

C/M Pain.

Blood in the anterior chamber.

Increase IOP.

Mgx Usually spontaneously recovers.

If sever bed rest, and eye shield application.

C. Orbital fracture It is fracture and dislocation of the wall of the orbit, orbital margin or both.Cause:- Injury on the cranial area.C/M Rhinorrhea. Contusion. Diplopia.Mgx May heal by itself, if no displacement or infringement on the other structure. Surgery:- repair of the orbital floor.D. Foreign body It is the presence of foreign material on the cornea or conjunctiva.

C/M Severe pain with lacrimation. Foreign body sensation. Photophobia. Redness. Swelling.Mgx Consider a medical emergency. Removal of foreign body through irrigation, cotton tipped applicator. Surgical removal.E. Laceration/Perforation.

It is cutting or penetration of soft tissue.

C/M Pain Bleeding Lacrimation PhotophobiaMgx Consider as medical emergency. Surgical repair- method of repair depends on the severity of injury. Antibiotics.F. Ruptured globe It is concussive injury to globe with tears in the ocular coat, usually the globe.

C/M Pain Altered IOP Limitation of gaze in field of rupture Hyphema hemorrhage Mgx Consider as medical emergency. Surgical repair Antibiotics Steroids Enucleation2.Burn of the eye

It is the destruction of the eye tissue by chemical, thermal, and ultraviolet ray.

A. Burn of chemical agent that is caused by alkali or acids.

C/M Pain Burning Lacrimation PhotophobiaMgx Consider as medical emergency.

Copious irrigation until PH is 7.

Keratoplasty for severe scaring.

Antibiotics.

B. Burns of thermal sourcesC/M Pain

Burned skin

Blisters

Mgx First aid-apply sterile dressing.

Pain control.

Leave fluid blebs intact.

Suture eyelid together to protect eye if perforation is possible.

Skin grafting with severe second and third degree burns.

C. Burn of UV sourceC/M Pain

Foreign body sensation

Lacrimation

Photophobia

Mgx Pain relief.

Bilateral patching with antibiotic ointment and cycloplegics.

Other eye condition1. Glaucoma (Disorder of an aqueous Humor Circulation)

Glaucoma is a pathological rise in the intra ocular pressure that causes damage to the various structure of the eye, especially the optic nerve.

It is the cause of blindness.

There are four types of glaucoma. These are;

1. Congenital .

2. Closed angle (acute).

3. Open angle (chronic)

4. Secondary.

1. Congenital glaucoma.

It is a rare condition that occurs in infant and neonates

C/M The diameter of the cornea increase in size.

The cornea becomes edematous

Dx Tonometry exam-increase IOP.

Mgx Medical-Pilocarpine drops, Acetazolamide tablet.

Surgical-Goniotomy-to incise the mesodermal membrane in the angle of anterior chamber.

2. Closed angle glaucoma It accounts for 10% of the primary glaucoma.

Etiology Mechanical blockage of the anterior chamber angle.

C/M A sudden severe pain in and around the eye.

Nausea and vomiting

Pupil mid-dilated and fixed.

Hazy appearing cornea due to corneal edema.

A sudden elevation of IOP

Dx Slit lamp exam nation.

Tonometry examination.

Mgx Medical

Lower the IOP as quick as possible by medical means.

Miotics- Used to constrict the pupil and contract the ciliary muscle, thus the iris is drawn away from cornea; aqueous humor may drain through lymph spaces (meshwork) ion to canal of schlemm.

E.g. Pilocarpine drops 2-4% every 5 minute fro an hour, and then every hour for 12 hour topically.

Carbonic anhydrase inhibitor-restricts action of the enzyme that is necessary to produce aqueshumor.

E.g. Acetazolamide (diamox)250mg QID.

Hyperosmotic agents-reduce IOP by promoting diuresis.

E.g. Mannitol IV.

Surgical Iridecomy- excision of a small portion of the iris where by AH can bypass. This prevents the periphery of the iris blocking the angle of the anterior chamber.

Trabeculectomy-partial thickness sclera, resection with small part of trabecular meshwork and iridectomy.

Laser iridotomy-multiple tiny laser incision to create openings for AH flow.

3. Open angle glaucoma Makes up 90% of primary glaucoma cases.

Its incidences is increased with age.

Etiology Degenerative changes occur in the trabecular meshwork and canal of schelmm.

Risk factors AGE.

Familial history of glaucoma.

Diabetes

Hypertension

C/M Mild, bilateral discomfort (tired feeling in the eyes, foggy vision).

Slowly developing impairment of peripheral vision with dilated pupil.

Progressive loss of visual field.

No pain or inflammation.

Dx Paleness of the optic disk.

Optic nerve atrophy.

Rise in IOP.

Mgx

Medical

Reduce the IOP by medication- the medication should be continued for the rest of the patient life

Pilocarpine drops 2-4% QID.

Adrenaline drops 1% BID.

Timolol/Timoptol/ drops ).25-0.5% BID.

Surgical

Iridencleisis- an opening is created b/n anterior chamber and space beneath the conjunctiva; this by pass the blocked meshwork, and AH is absorbed into conjunctival tissues.

Cyclodiathermy/Cylocryotherapy-destruction of ciliary body with a high frequency electrical current or supercooled probe.

4. Secondary glaucoma. It is a type of glaucoma caused by a specific causes or pathologies.

Etiology Hemorrhage.

Corticosteroid use.

Uveitis.

Mgx Treat the cause.

2. Strabismus/Squint

It is the situation where by the two eyes are looking in different directions.

Etiology

Disorder of vision.

Disorder of the eye movement secondary in the abnormality on the muscle that controls the movement.

Effects of squint In adults

Double vision/diplopia/.

Abnormal head posture.

In children Ambylopia/lazy eye/.

C/M The corneal light reflex.

This is the best and simplest test of squint.

If the two eyes are straight, then the two corneal light reflexes are central and symmetrical, but if one eye squints, then the reflex deviates from the center of the cornea.

Testing the ocular movements.

There are six extra ocular muscle, and each one produces most of the movement in the particular direction.

MgxIn children Try to correct any refractive errors and ambylopia before straightening the squint surgically.

Patching the good eye.

Surgical correction by either weakening, straightening or realigning the extra ocular muscles

In adults Cosmetic surgery is the only treatment.

3. Diabetic Retinopathy Is a frequent complication of DM.

Occur after 20years of having DM.

Caused by damage to or occlusion of the blood vessels those nourish the retina. Weakened blood vessels become hyper-permeable & leak, causing micro-hemorrhages, retinal swelling, or exuadative deposits.

Progressive retinal ischemia stimulates the formation of new blood vessels (neovascularization).

These new vessels are fragile & may rapture, causing sub retinal hemorrhage or bleeding. The vitreous body also, they may form fibro vascular bands that contract, resulting in traction & subsequent retinal detachment.

There are five stages of diabetic retinopathy. Background retinopathy

Occurs in most diabetics about 20years after the onset of the disease.

Has no symptom until macula is involved.

C/M: - The fundus has dots (Micro - Aneurysms), blots (Small hemorrhage), & hard waxy exudates (leakages of lipids from the hemorrhaging blood vessels.

Maculopathy

It is main cause of visual impairment in non insulin dependent DM.

Pre Proliferative retinopathy

Occurs in eyes with background retinopathy only.

C/M: - The retina is ischemic which causes;

Cotton wool spot

Dilation, beading, looping of blood vessels

Arteriole narrowing

Large dark blot hemorrhage

Proliferative retinopathy

Is the main cause of visual impairment in IDDM.

Advanced retinopathy

It is the end result of uncontrolled proliferative retinopathy & results in blindness.

Generally C/M of Diabetic retinopathy is;

If fluid collects at the macula, the patient notices blurred central vision.

Vitreous hemorrhage in cloudy or hazy vision of sudden onset.

Mgx

Laser photocoagulation surgery is useful. An intense beam of laser light is used to seal of leaking blood vessels & destroy abnormal new ones.

Control DM.

4. Retinal detachment

Retinal detachment occurs when there is a separation of the neuro-sensory retina from the underlying pigment epithelium layer of the retina.

Neurosensery retina contains: - rods & cones.

Causes: - The neural retina can be either pulled, pushes or floated off the underlying epithelial layer

Pulled off: - by vitreous traction, which occurs when new blood vessels have grow in to the vitreous.

This condition con be caused by;

DM.

Retinal hemorrhage .

Vitreous hemorrhage.

Pushed off: - A lesion behind the retina . such as choroidal tumors, hemorrhage, choroiditis & retinopathies

Floated off :- If a tear or hole appears in the retina, subretinal fluid or vitreous fluid enters the hole, floating the neural layer off the epithelial layer. Rhegmatagenaus ( tear induced ) detachment - is most common type.

In general the causes can be;

congenital malformation

Metabolic disorders

Vascular disease

Neoplasm

trauma

Degenerative changes

C/F: - History of floating or flashing lights or both. The floaters are perceived as tiny dark spots or cobwebs.

Spreading shadow or curtain moving across the field of vision, resulting in blurred vision & loss of visual field as the retina separates

Decreased central acuity or lass or central vision

Flashing lights (photopia).

Medical-Surgical Nursing-II, Eye Disorder Prepared by Tesfa D. (B.Sc. in Nursing) Page 3