Recurrent corneal erosion is a disorder of the eyes characterized by the failure of the cornea's outermost layer of epithelial cells to attach to the underlying basement membrane (Bowman's layer). The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves. This condition can often leave patients with temporary blindness due to extreme light sensitivity (photophobia).
Signs and symptoms
Symptoms include recurring attacks of severe acute ocular pain, foreign-body sensation, photophobia (i.e. sensitivity to bright lights), and tearing often at the time of awakening or during sleep when the eyelids are rubbed or opened. Signs of the condition include corneal abrasion or localized roughening of the corneal epithelium, sometimes with map-like lines, epithelial dots or microcysts, or fingerprint patterns. An epithelial defect may be present, usually in the inferior interpalpebral zone.
Cause
Most cases of recurrent corneal erosion are acquired. There is often a history of recent corneal injury (corneal abrasion or ulcer), but also may be due to corneal dystrophy or corneal disease. In other words, one may develop corneal erosions as a result of another disorder, such as map-dot fingerprint dystrophy. Familial corneal erosions occur in dominantly inherited recurrent corneal erosion dystrophy (ERED) in which COL17A1 gene is mutated.
Diagnosis
The erosion may be seen by an eye doctor using the magnification of a biomicroscope or slit lamp. Usually fluorescein stain must be applied first and a cobalt blue-light used, but may not be necessary if the area of the epithelial defect is large. Optometrists and ophthalmologists have access to the slit lamp microscopes that allow for this more-thorough evaluation under the higher magnification. Mis-diagnosis of a scratched cornea is fairly common, especially in younger patients.
Prevention
Given that episodes tend to occur on awakening and managed by use of good 'wetting agents', approaches to be taken to help prevent episodes include:
Environmental
ensuring that the air is humidified rather than dry, not overheated and without excessive airflow over the face. Also avoiding irritants such as cigarette smoke. use of protective glasses especially when gardening or playing with children.
General personal measures
maintaining general hydration levels with adequate fluid intake. not sleeping-in late as the cornea tends to dry out the longer the eyelids are closed.
Pre-bed routine
routine use of long-lasting eye ointments applied before going to bed. occasional use of the anti-inflammatory eyedrop FML (prescribed by an ophthalmologist or optometrist) before going to bed if the affected eye feels inflamed, dry or gritty use of a hyperosmotic (hypertonic) ointment before bed reduces the amount of water in the epithelium, strengthening its structure use the pressure patch as mentioned above. use surgical tape to keep the eye closed (if Nocturnal Lagophthalmos is a factor)
Waking options
learn to wake with eyes closed and still and keeping artificial tear drops within reach so that they may be squirted under the inner corner of the eyelids if the eyes feel uncomfortable upon waking. It has also been suggested that the eyelids should be rubbed gently, or pulled slowly open with your fingers, before trying to open them, or keeping the affected eye closed while "looking" left and right to help spread lubricating tears. If the patient's eyelids feel stuck to the cornea on waking and no intense pain is present, use a fingertip to press firmly on the eyelid to push the eye's natural lubricants onto the affected area. This procedure frees the eyelid from the cornea and prevents tearing of the cornea.
Treatment
With the eye generally profusely watering, the type of tears being produced have little adhesive property. Water or saline eye drops tend therefore to be ineffective. Rather a 'better quality' of tear is required with higher 'wetting ability' (i.e. greater amount of glycoproteins) and so artificial tears (e.g. viscotears) are applied frequently.
Nocturnal Lagophthalmos (where the eyelids do not close enough to cover the eye completely during sleep) may be an exacerbating factor, in which case using surgical tape to keep the eye closed at night can help.
Whilst individual episodes may settle within a few hours or days, additional episodes (as the name suggests) will recur at intervals.