Recurrent Corneal Erosion
It might be helpful in understanding this condition if you were to visualize a freshly tiled kitchen floor...that’s right a kitchen floor the old fashioned kind with 12-inch square tiles fastened to the floor with an adhesive. Hold this thought.
Back to the cornea
If you were to look at a cross-section of a human cornea under a microscope you’d see that it consists of 5 identifiable layers. In the context of recurrent erosion syndrome we are primarily interested in the top layer of corneal cells called the epithelium.
Think of the individual corneal epithelial cells on the surface of your cornea as tiles on your kitchen floor. Similar to the tiles being fastened to a sub-floor normal corneal epithelial cells are firmly attached to a thin underlying “basement membrane”. Epithelial cells are also very tightly attached to their neighbours. This firm adherence both to the basement membrane below and to each neighbouring cell makes for a firm seal on the surface of the cornea which protects the eye from invading microorganisms and toxins.
Recurrent erosion syndrome (RES) refers to repeated episodes of a group (or several groups) of corneal epithelial cells losing their attachment sloughing away and causing painful symptoms.
What are the symptoms?
If you’re like most people with RES you’ve been experiencing mild to severe eye pain redness tearing and light sensitivity particularly in the morning upon awakening. Certain people have also reported blurred vision. During deep sleep our eyes actually move around a lot rubbing against the corneal epithelium. If the epithelial cells are abnormally loosely attached they can be easily dislodged completely pulling away from their attachment upon awakening and opening the eyelids. OUCH!!!
Typically recurrent corneal erosions occur in eyes previously afflicted by a sharp abrading injury such as from a fingernail or paper cut. This particular kind of tissue-tearing injury often results in the improper or inadequate healing of the basement membrane which causes the eye to become prone to recurrent erosions in the future.
Some patients are particularly prone to recurrent erosions because they have a common underlying abnormality of the basement membrane-epithelial cell attachment called epithelial basement membrane dystrophy (EBMD).
Recurrent corneal erosions are usually not limited to one eye and occur somewhat more frequently in females than in males. RES and EBMD sufferers are typically above the age of 40.
Treatment for RES?
Today a great deal can be done to prevent your corneal epithelial cells from eroding. Your eye doctor will most likely recommend that you begin aggressively lubricating your eyes with artificial tears. Depending on the severity of your RES you may need to use over-the-counter preservative-free artificial tears for a minimum of four times per day combined with artificial tear ointment at bedtime.
If aggressive lubrication offers little help a therapeutic bandage soft contact lens may be used to prevent further erosions. In an attempt to prevent further corneal abrasions and promote better healing this specially designed contact lens may need to remain on the eye without removal for a period of several weeks to several months.
Most patients recover completely with aggressive lubrication and/or placement of a bandage contact lens. But for those individuals who remain symptomatic with RES there are other highly successful treatments that can be performed either surgically or using laser technology.
A new approach to treatment
It has been postulated that a group of enzymes called matrix metalloproteinases can degrade the epithelial cell attachment complexes thus hindering the healing of the epithelial cells following cutting types of corneal injuries resulting from fingernails paper cuts etc.
A recent study demonstrated that corticosteroid and tetracycline eye drops decreased the activity of metalloproteinase enzymes. Certainly more research in this area needs to be done but this is good news for the RES sufferer.