Effect of iris registration on outcomes of FEMTOLASIK for myopia and myopic astigmatism.

Abstract

To compare the visual and refractive outcomes after FEMTOLASIK with and without iris registration. In this randomized, prospective, comparative, contralateral eye study, 118 eyes of 59 patients with myopia and myopic astigmatism underwent LASIK using the Femto LDV femtosecond laser (160µm) and the MEL80 with or without iris registration. For each patient, iris registration FEMTOLASIK was performed on one eye and non-iris registration FEMTOLASIK was performed on the other eye, assigned at random. Patients were evaluated before and 12months. Uncorrected visual acuity, best-corrected visual acuity, manifest refraction, contrast sensitivity, and higher-order aberrations (HOAs) were evaluated. At 12months, the mean UDVA was 0.002±0.07 logMAR (20/19) in iris registration eyes and 0.00±0.06 logMAR (20/24) in non-iris registration eyes (P=0.9). 61% of iris registration eyes and 71.2% of non-iris registration eyes achieved a UDVA of 20/20 or better (P=0.31); 98.3% of eyes with the iris registration FEMTOLASIK and 94.9% with the non-iris registration FEMTOLASIK were within ±0.50D from emmetropia (P=0.71). No statistically significant difference was found in postoperative contrast sensitivity between groups at 3, 6, 12, or 18 cycles/degree (P>0.05). There was significant increase in total HOA root mean square in two groups. The mean error magnitude of surgically induced astigmatism 12months postoperatively was -0.33 in iris registration eyes and -0.24 in the non-iris registration eyes (P=0.36). FEMTOLASIK with and without iris registration provides similar results in myopic and myopic astigmatism patients.