The purpose of this study is to investigate the possible effect of hinge location on corneal sensation and dry eye syndrome after laser in situ keratomileusis (LASIK).

Dry eye symptoms are a frequent postoperative complication of laser in situ keratomileusis (LASIK). Although estimates of the incidence of dry eye syndrome vary widely, from 3% to 59%, almost all patients will have transient dry eye during the immediate postoperative period.Because of the variability in corneal innervation patterns, altering flap characteristics in LASIK may affect postoperative corneal sensation and dry-eye disease. Some studies have reported that postoperative corneal sensation may be higher and recovery faster in eyes with horizontal flaps (nasal- or temporal-hinge) than in eyes with vertical flaps (superior- hinge). However, some other studies have not established an association between corneal sensation and hinge position. This study reviewed the published literature and performed a meta-analysis aimed to investigate the effects of hinge location on corneal sensation and dry-eye symptoms after LASIK.

Inclusion Criteria:

1. each trial should be a prospective randomized controlled clinical trial (RCT),
2. the age of patient population should be over 18 years

Exclusion Criteria:

1. non-randomized controlled trials
2. patients who had had a previous ophthalmic surgery or ocular surface disorders
3. the raw data was not completed

patients were scheduled to undergo LASIK and randomized to different hinge locations