Dry Eye Syndrome

Cause
The corneal nerves are transected creating a neurotrophic cornea,which can
result in neurotrophic epitheliopathy. This neurotrophic effect decrease the
feedback loop to the lacrimal land and cause a secondary decrease in tear
production and dry eye condition. The surface of the reshaped cornea may not
hold the tear film as well as before, causing secondary wetting problem
The microkeratome may damage the gobblet cells and microvilli,causing s
corneal surface problems. An abnormally low Schirmer’s test result, low tear
break-up time (TBUT), and conjuctival and corneal staining with fluorescein, rose
bengal or lissamine green are indicative of possible preoperative dry eye
syndrome, which predisposes the patient to such problems postoperatively
Low ambient humidity such as occurs during winter months in northern climates
Blepharitis and meibomianitis may also predisposes to surface problems after
LASIK surgery
Prevention
Treat dry eye syndrome preoperatively with a combination of artificial tear
supplements, topical cyclosporine (Restasis), and punctal plugs Treat blepharitis
preoperatively Consider performing a nasal hinge LASIK flap Consider a surface
ablation procedure Consider avoiding keratorefractive surgery when the surface
problems can’t be satisfactorily improved prior to surgery