Abstract
Purpose: :
Investigate whether a femtosecond laser inverted sidecut bevel can prevent resection of the vital peripheral corneal fibers and improve postoperative corneal sensation.
Methods: :
In a prospective comparison, 40 eyes of 20 consecutive patients underwent bilateral simultaneous myopic LASIK with 150-kHz femtosecond laser flaps and wavefront-guided ablations. In half the eyes, an elliptical flap with 150-degree reverse sidecut angles and a 4.00-mm hinge was created. The other 20 eyes had traditional round flaps with 70-degree sidecut angles and 3.00-mm hinges. All flaps were 110 microns thick, with nasal hinges and a stromal diameter of 8.5 mm. Cochet-Bonnet esthesiometry was performed preoperatively and at 1 day, 1 week, 1 month, and 3 months postoperatively.
Results: :
Prior to surgery, corneal sensation was 5.87 cm in the elliptical/reverse sidecut flap (RSC) group and 5.80 cm in the conventional femtosecond flap group. At 1 week, corneal sensation had decreased to 3.54 cm in the RSC group and 2.67 cm in the conventional group. In the RSC group, corneal sensation gradually improved to 4.26 cm at 1 month and near baseline levels (5.54) at 3 months. In the conventional group, corneal sensation improved (to 3.35 cm at 1 month and 4.48 cm at 3 months) but did not return to baseline levels. The elliptical flaps also provided greater stromal bed exposure and a wider hinge for improved flap stability
Conclusions: :
An elliptical flap that prevents resection of the vital peripheral corneal fibers, combined with an inverted flap sidecut that improves severed nerve apposition, results in improved corneal sensation following LASIK.
Clinical Trial: :
www.clinicaltrials.gov 4352590
Keywords: refractive surgery: LASIK • wound healing • cornea: tears/tear film/dry eye