What is it?
A corneal abrasion is a traumatic erosion of the corneal surface.
It is usually confined to the epithelium because the membrane at the epithelial base (Bowmman's membrane) is very strong.
Most corneal abrasions occur from accidental contact by fingernails, hairbrush bristles, branches or bushes, and from poor contact lens technique or overwear.
Here's the problem: a traumatic erosion can be mimicked by a surface infection. So if there is no clear history of trauma or contact lens wear, be suspicious of an infectious keratitis. The major concern is herpes keratitis, particularly if the erosion has a .
The patient will complain of a foreign body sensation. Penlight exam may show an area of corneal haze or a broken up light reflection. This can be very subtle, and is better seen by instilling fluorescein dye.
What to do?
- Instill a topical anesthetic in order to allow pain-free examination.
- Measure visual acuity.
- Inspect the cornea with penlight and loupe or biomicroscope magnification.
- Instill fluorescein dye and examine under cobalt blue light if possibleit enhances fluorescence.
- Evert the upper eyelid to make sure there isn't a foreign body hiding in the pre-tarsal sulcus. Remove any that you find there.
- Instill a topical antibiotic and arrange follow-up examination in 24 hours to make sure the corneal abrasion has healed. Prescribe pain medication for that interval, as pain can be considerable, although short-lived. Patch firmly to relieve pain unless you suspect infection.