PURPOSE: To investigate the effect of hinge width on corneal sensation and dry-eye syndrome after laser in situ keratomileusis (LASIK). SETTING: TLC Laser Eye Center, Garden City, New York, USA. METHODS: Fifty-four patients at least 18 years of age had bilateral LASIK with a narrow nasal hinge microkeratome flap in 1 eye and a wider nasal hinge microkeratome flap in the other eye. In all eyes, the flaps were 160 microm in thickness with a diameter of 9.5 mm. Masked Cochet-Bonnet esthesiometry was performed in the central cornea preoperatively and at 1 week and 1, 3, and 6 months. Dry eye was evaluated at the same intervals by lissamine green corneal and conjunctival staining, Schirmer test with anesthesia, and tear-film breakup time. RESULTS: Corneal sensation was significantly reduced from preoperative levels through 6 months in the narrow-hinge group and through 3 months in the wider-hinge group (P< or =.002). The mean corneal sensation was greater in corneas with a wider hinge flap than in those with a narrow hinge flap at all postoperative examinations; the difference was significant at 1 and 3 months (P< or =.002). The loss of sensation was greatest at 1 week and improved at all subsequent examinations. Overall, dry-eye signs and symptoms were greatest immediately postoperatively and improved at subsequent intervals. CONCLUSIONS: Corneal sensation and dry-eye signs and symptoms improved at all intervals between 1 week and 6 months. The loss of corneal sensation and presence of dry-eye syndrome were greater in eyes with a narrow hinge flap than in eyes with a wider hinge flap.
PURPOSE: To investigate the effect of hinge width on corneal sensation and dry-eye syndrome after laser in situ keratomileusis (LASIK). SETTING: TLC Laser Eye Center, Garden City, New York, USA. METHODS: Fifty-four patients at least 18 years of age had bilateral LASIK with a narrow nasal hinge microkeratome flap in 1 eye and a wider nasal hinge microkeratome flap in the other eye. In all eyes, the flaps were 160 microm in thickness with a diameter of 9.5 mm. Masked Cochet-Bonnet esthesiometry was performed in the central cornea preoperatively and at 1 week and 1, 3, and 6 months. Dry eye was evaluated at the same intervals by lissamine green corneal and conjunctival staining, Schirmer test with anesthesia, and tear-film breakup time. RESULTS:Corneal sensation was significantly reduced from preoperative levels through 6 months in the narrow-hinge group and through 3 months in the wider-hinge group (P< or =.002). The mean corneal sensation was greater in corneas with a wider hinge flap than in those with a narrow hinge flap at all postoperative examinations; the difference was significant at 1 and 3 months (P< or =.002). The loss of sensation was greatest at 1 week and improved at all subsequent examinations. Overall, dry-eye signs and symptoms were greatest immediately postoperatively and improved at subsequent intervals. CONCLUSIONS:Corneal sensation and dry-eye signs and symptoms improved at all intervals between 1 week and 6 months. The loss of corneal sensation and presence of dry-eye syndrome were greater in eyes with a narrow hinge flap than in eyes with a wider hinge flap.