Dry eye (or "dry eye syndrome") is common during the immediate recovery period after LASIK. Symptoms include burning, irritation, foreign body sensation (feeling something is "in" the eye), and fluctuating vision. While a nuisance, for most patients postoperative dry eye is usually not a serious problem. Dryness symptoms typically return to their preoperative level over time, although it can take several months for this to happen.
But a small percentage of patients have significant problems with dry eyes after LASIK. Often, these patients have dry eyes prior to surgery, and the condition worsens in response to the laser treatment. There are several reasons for increased dryness symptoms after LASIK:
- Corneal nerve damage. Both the creation of the corneal flap and the laser treatment in LASIK damages some corneal nerves that are important in the production of tears. Many of these nerve endings will regenerate over time, restoring normal or near-normal tear secretion. However, this process can take 6 months or longer.
- Devitalized goblet cells. Certain cells involved in maintaining good surface wetting on the cornea are damaged when the microkeratome or femtosecond laser suction ring is seated onto the eye to create the corneal flap during LASIK. These "goblet cells," as they are called, take time to regenerate.
- Deficient tear oil layer. The tear film on the eye includes a thin layer of oil that slows the evaporation of tears. This oil is produced by glands (called Meibomian glands) in the upper and lower eyelids that empty their contents onto the eye at the eyelid margin. In a condition called Meibomian gland dysfunction (MGD), these glands either become plugged or fail to secrete adequate amounts of oil. Without a good oil layer, the tear film quickly evaporates and causes irritation. Patients with Meibomian gland dysfunction prior to LASIK are predisposed to dry eyes after surgery.
- Incomplete lid closure or blink. Many patients unknowingly don't close their eyes completely when sleeping or don't completely blink. In either case, the eye remains more exposed to the environment and is exposed eye is susceptible to drying and irritation. Patients with incomplete lid close or partial blinking are more prone to dryness problems after LASIK.
Current dry eye therapies are:
- Artificial tears and lubricating ointments
- Punctal occlusion (punctal plugs)
- Treating Meibomian gland dysfunction
- Cyclosporine eye drops (i.e. Restasis)