Corneal abrasions and f bs

EMERGENCY DEPARTMENT REGIONAL TEACHING SERIES

JF POTTS, EA WINN

Corneal Abrasions and Foreign Bodies

Basic Corneal Anatomy

Transparent avascular tissue with a convex anterior surface and concave posterior surface

Main function is opticalAccounts for 70% of total

refractory surface of the eyeAlso acts as protection to the

eye and structural integrity

What are corneal abrasions?

Corneal abrasion is the most common eye injury.They frequently result from eye trauma, retained

foreign bodies, and improper contact lens use. It occurs because of a disruption in the integrity of

the corneal epithelium or because the corneal surface is scraped away or denuded as a result of physical external forces.

As they usually heal rapidly, without serious sequelae they are often considered of little consequence.

However, deep corneal involvement may result in facet formation in the epithelium or scar formation in the stroma.

Clinical Presentation

The corneal epithelium is richly innervated with sensory pain fibers from the trigeminal nerve (cranial nerve V).

Therefore patients with corneal abrasions of all types have the same clinical presentation;

- severe eye pain- reluctance to open the eye due to photophobia- foreign body sensation

Patients with traumatic abrasion have a history of direct trauma to the globe.

Patients with a foreign body may or may not recall an episode with material falling or flying into the eye since, depending upon the type and size of the foreign body.

If the FB entered the eye at high velocity (e.g. when using a grinding machine or from metal striking metal) you MUST consider the possibility of a penetrating eye injury and modify the subsequent examination as clinical findings require.

History (in addition to your usual questions)

Document time, place and activity during injuryDocument the complaint (common abrasion

symptoms include; foreign body sensation/painful eye/watery eye and secondary blurred vision/photophobia)

Is it a recurrent problem? Did they wake up with it?

Past ophthalmic history: Do they wear contact lenses? Any previous eye problems? Any eye surgery?

Past medical history: arthritis? Atopy?Drugs: any drops? Allergies?

Examination

MUST record visual acuities in both eyes—use the patient's own glasses and then add the pinhole on top of that

MUST use the slit lamp or direct ophthalmoscope on high magnification—ask a senior if necessary

MUST examine both eyesIs there any purulent discharge from

the eyes? Check pupils circular and reactive

Always evert and check under the lids to assess for a conjunctival FB

Instil fluorescein dye (with topical local anaesthetic) and examine with cobalt blue light

Examination continued

Draw a diagram of the eye with abrasion (the area of staining)Describe the position and size of abrasion. Is it in the

centre or periphery of the cornea? Is it clear or is there associated infiltrate/ulcer?

Comment on the anterior chamber looking for cells/ layering purulence (hypopyon).

Assess for perforated globe/foreign body (Seidel Sign). If FB seen, attempt removal with spud or 20G/25G (tangential approach) needle after anaesthetising eye. If unable to remove URGENT OPTHAL REFERRAL.

Those without formal training should not approach the globe with sharp instruments; an appropriately trained clinician should be consulted if removal with a swab is unsuccessful

 Management

CHLORAMPHENICOL ointment BD to the affected eye for 5 days

If they are very photophobic, put 1 drop of CYCLOPENTOLATE in the eye

Advise ibuprofen or, if required, give codeine based analgesia in addition

Patch the eye for 4–6 hours if the abrasion is very painful. Or >50% of corneal surface. Never patch an ulcer.

Removal of rust ring on a routine basis at time of foreign body removal is not recommended because of potential damage to Bowman’s membrane and resultant scarring

DON'T GIVE OUT TOPICAL ANAESTHETICS to take home

Advise them to not wear contact lens for 2 weeksAdvise them it may be painful for 2 days

Management continued

NB: If there is an infected ulcer (if you see any discharge, infiltrate in the abrasion or pus in the anterior chamber), significant visual loss or a history of penetrating injury- RING OPTHALMOLOGY ON CALL for advice

Patching technique:

Apply topical antibiotic treatment

Ensure lid is closed over corneal and tape gauze pad over eyelid

Generally not required for small abrasions

Indicated for: - 1) Very symptomatic and

photophobic patients- 4-6hr patching, possible benefit.

- 2) Large abrasions >50% corneal surface- 24hr patch.

Follow up

Most corneal abrasions can be discharged without any follow up. However, if unsure bring back to ED in 24 hours. Ask the patient to return to A&E if they do not feel any improvement in 72 hours.

Reasons for follow‐up in Opthalmology clinic: If there is corneal ulcer/infiltrate (white spot or opacity indicating

ulceration) or hypopyon Visual loss (>2 lines on Snellen chart) The abrasion is affecting the patient's “only‐seeing” eye The patient gives a history of recurrent abrasion in the same eye Contact lens wearer with corneal ulceration Concern for retained foreign body Large defect > 40% of corneal Delayed healing- failure to re-epithelialise after 3-4 days If senior opinion is sought then please document who advised and

the advice that was given

Conclusion

Corneal abrasions are common eye injuries that frequently result from eye trauma, foreign bodies, and improper contact lens use.

Patients typically present with severe eye pain and a foreign body sensation.

Key aspects of clinical evaluation include exclusion of an open globe and hyphema, measurement of visual acuity, penlight and fluorescein examination, and lid eversion to assess for a conjunctival foreign body.

Treatment of small, uncomplicated corneal abrasions consists of topical antibiotic therapy and either topical or oral pain medication. Most abrasions heal fully within 24 hours.