Results of flap repositioning after laser in situ keratomileusis

Abstract

Purpose To determine the incidence and severity of flap folds and displacement after laser in situ keratomileusis (LASIK) and assess the outcome of the flap repositioning procedure. Setting Eye Institute of Utah, Salt Lake City, Utah, USA. Methods Charts of 91 eyes of 87 patients that had flap repositioning were reviewed retrospectively. Four patients had bilateral procedures. Results The overall rate of flap repositioning was 0.91%. Fifty-six percent of flap folds occurred on the first postoperative day and 85%, within 1 week of the LASIK procedure. The latest flap repositioning was performed 150 days after LASIK. Blurred vision was the main symptom; this occurred in 72% of patients. Eighteen percent of eyes had loose epithelium at the time of LASIK. Dry eye was found in 42% of cases. Nineteen percent of eyes had multiple flap repositioning procedures. Flap folds induced a hyperopic change in refraction and increased astigmatism as well as irregular astigmatism. With the Automated Corneal Shaper® (ACS) microkeratome (Bausch & Lomb Surgical), 45% of folds were located in the superior part of the flap and 6% in the inferior part; 42% of folds were oriented horizontally and 17%, vertically; 23% of eyes had a superior gutter. With the Hansatome® (Bausch & Lomb Surgical) microkeratome, 73% of folds were central; 87% were oriented vertically and 6%, horizontally. The incidence of flap folds increased to 2.10% with the use of the Hansatome. With a mean follow-up of 8.3 months after flap repositioning (range 3 to 31 months), the uncorrected visual acuity was 20/20 in 59% of eyes and 20/40 in 88%. Three eyes (3%) lost 2 or more lines of best corrected visual acuity. The final spherical equivalent was –0.07 diopter (D) ± 0.61 (SD), and 87% of eyes were within ±1.00 D of emmetropia. Conclusion Flap repositioning significantly restored the vision loss caused by flap folds and displacement. However, irregular astigmatism due to permanent residual folds remains the main factor affecting the visual and refractive outcome.