Q. I sometimes wake up in the morning with severe pain in one eye. What could cause that?
The most likely culprit is recurrent corneal erosion syndrome (RCES), according to Marlon Maus, M.D., an ophthalmologist and professor of public health at UC Berkeley and a member of our editorial board.
This common condition (Dr. Maus treated dozens of cases a week as director of emergency services at a Philadelphia eye hospital) occurs when the epithelium—the outermost layer of cells on the cornea (the clear, dome-shaped disk over the iris and pupil)—doesn’t properly adhere to the layer of cells just underneath, called the basal lamina. When the eyelid opens upon waking, it causes some of the poorly attached epithelial cells to rip away from the cornea.
The condition is characterized by pain (in some cases severe), a “scratchy” feeling, blurred vision, redness, sensitivity to light, and tearing. Symptoms can persist for a few minutes to several hours or even all day.
The most common cause of RCES is physical trauma—a scratch from a fingernail or tree branch, for example, or a foreign object getting into the eye. In some cases, the trauma occurred years earlier, suggesting that the cornea never healed properly.
Other possible causes include dry eye (in which your eye produces insufficient or poor-quality tears), a previous corneal infection, hereditary abnormalities in the cornea, diabetes, ocular rosacea (rosacea that affects the eye), and nocturnal lagophthalmos (a condition in which the eyelid doesn’t close completely at night, allowing the eye to dry out). Sometimes there is a combination of causes. Usually, RCES affects just one eye (or one eye at a time), but depending on the underlying cause, it may in rare cases occur in both eyes simultaneously.
If you have recurrent eye pain or any of the other symptoms listed above, consult an eye doctor (ophthalmologist or optometrist), who will likely examine the eye using a special microscope called a slit lamp, along with a dye (fluorescein) that helps the doctor see the corneal cells. If RCES is diagnosed, you will probably be instructed to use an over-the- counter (OTC) lubricating ointment at bedtime and OTC artificial tears during the day to keep the eye moist. (If your pain is mild, you could try these OTC products at home first before seeing a doctor.) You might have to keep using the ointment and tears indefinitely to help prevent a recurrence. You may also be prescribed a course of antibiotic eye drops.
For severe discomfort, the doctor might prescribe pain-relieving eye drops. These dilate the pupil, so you won’t be able to drive or read after using them.
If these steps don’t help enough, and if the problem is mainly due to dry eye, an ophthalmologist can insert temporary or semi-permanent plugs into the tear ducts (punctal plugs), which encourages moisture to remain on the eye. You might also get a soft “bandage” contact lens to wear continuously (usually for up to 30 days at a time) while the cornea heals, which can take as long as two months.
In addition to any formal therapies, two simple steps can help you prevent or manage RCES by lessening the chance of your eyes becoming dry overnight: Sleep with a humidifier in the room, and avoid having air blowing directly on your face.
