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Effect of thin femtosecond LASIK flaps on corneal sensitivity and tear function.

PURPOSE
To evaluate changes in comeal sensitivity and tear function following myopic LASIK with thin femtosecond flaps.


METHODS
A retrospective study was performed to compare corneal sensitivity (filament), tear breakup time, and anesthetized Schirmer test preoperatively and at 1 week and 2 and 6 months postoperatively.


RESULTS
Seventy-two eyes of 38 consecutive patients (20 women and 18 men) who underwent LASIK for myopia or myopic astigmatism with thin femtosecond flaps (IntraLase femtosecond laser system and Technolas 217 PlanoScan V2.9992 or wavefront-guided Zyoptix 3.1 excimer laser) were evaluated. Preoperative mean corneal sensitivity was 5.3+/-1.5 mm, which decreased to 4.6+/-1.7 mm at 1 week, increased to 5.0+/-1.3 mm at 2 months, and returned to baseline values at 6 months postoperatively. Mean Schirmer score was 13.7+/-5.7 mm preoperatively and 12.1+/-5.1, 13.1+/-4.8, and 13.0+/-5.1 mm at 1 week and 2 and 6 months postoperatively, respectively. Mean tear breakup time was 7.7+/-2.6 seconds preoperatively and 7.8+/-3.5, 9.2+/-4.6, and 8.8+/-4.5 seconds at 1 week and 2 and 6 months postoperatively, respectively. No significant increase in fluorescein staining was observed throughout follow-up.


CONCLUSIONS
Reductions in corneal sensitivity and tear function tests were minimal after myopic LASIK with thin femtosecond flaps. Despite the relatively narrow hinge, the thin, uniform femtosecond flap does not appear to have an adverse effect on corneal sensitivity and dry eye signs at 6 months postoperatively.