subject: Dry eye after LASIK [print this page] Dry eye after LASIK Dry eye after LASIK
Dry eye syndrome refers to a substandard tear film due to reduced volume of tears or too fast tear evaporation. The disease gives rise to a number of symptoms such as burning, itching, foreign body sensation, high sensitivity to light, graininess, and other eye problems.
The tear film has three components: an outer layer of fatty substances secreted by the meibomian glands, a middle layer of watery tears produced by the lachrymal glands, and an inner layer of mucous produced by the goblet cells in the conjunctiva, the inner lining of the eyelids.
Symptoms of dry eye may be experienced because of deficient aqueous tears production, more rapid evaporation (due to inadequate lipid secretions), or mechanical causes such as poor blink distribution. With the rising popularity of surgery to treat refractive errors in the eye, particularly LASIK, there incidence of dry eye has risen.
LASIK (laser in situ keratomileusis)
Laser-based refractive surgery has several common approaches, but there is greater preference for technique is LASIK. Corneal realignment is the primary objective of refractive surgery. Only a normal cornea can bend light rays properly toward the retina to enable properly focused vision. Once the cornea is properly aligned, light is targeted to hit directly onto the retina, correcting problems of vision and removing the need for contact lenses or spectacles.
You may decide to have LASIK surgery because you want spectacles and contact lenses. You may have become weary of wearing and caring for the contacts, and spending money on replacements and cleansers. Besides, long-term use of contact lenses may have caused dry eye symptoms. Unfortunately, dry eye syndrome can be just as present, and just as painful, after LASIK.
LASIK surgery has high impact, inflicting damage on the nerve network serving the cornea. It is necessary to cut out a flap in the centre of the cornea, slicing through the outer layer (epithelium) of the cornea to reach the inner layers (stroma). It is necessary to burn a tiny patch of inner tissue with the laser, in order to reshape the cornea. The surgery takes only a few minutes, with little or no pain or discomfort during surgery.
It is quite likely you'll suffer dry eye problems in the first month after LASIK. But as healing proceeds over time, the dry eye problems lessen, and are fully resolved after about six months. This, of course, is the objective. For many, however, the dry eye remains; for some, it can get worse.
Dry eye syndrome can emerge after surgery due to many factors. Some corneal nerves are severed during surgery, causing the cornea to lose sensation (this is called LASIK-induced neurotrophic epitheliopathy, or simply LINE). The loss of sensitivity deadens the triggers for the lachrymal glands and deactivates their capability to secrete tears, so aqueous tear production abates. A similar interruption happens to the nerve impulses that induce stimulate lipid secretion in the meibomian glands. The normal blink can also be adversely affected, as well as the mucous secretions of by the goblet cells for the tear film. The overall effect is an inferior quality tear film and a cornea with a flatter curvature and reduced capability to maintain a fully protective tear film.
Management of Dry Eye after LASIK
Even before actual LASIK surgery, dry eye management should already be carried out. During prepatory preparations, the physician should find out if you are already showing signs or symptoms of dry eye disease, including blepharitis, contact lens intolerance, etc. Any eye health conditions existing before surgery can magnify the post-operative effects of LINE. Ideally, these symptoms should be completely resolved before surgery takes place.
The doctor may also prescribe artificial tears to provide added lubrication to the eye. However, the mainstay of treatment is topical cyclosporine in a castor oil base. This is usually applied both before and in the months after LASIK surgery. Taking omega-3 fatty acid supplements may also be advised, especially where the patient is not responding well to topical cyclosporine or the the medication is not available.
