A comparison of visual acuity, predictability, and visual function outcomes after intracorneal ring segments and laser in situ keratomileusis. Suiter BG, Twa MD, Ruckhofer J, Schanzlin DJ. Tr Am Ophth Soc 2000;98:51–57.

Abstract

The authors compared the correction of low myopia by intrastromal corneal ring segments (IRCS) and by laser in situ keratomileusis (LASIK) with respect to early visual recovery and refractive outcomes. Eighty-two eyes implanted with ICRS in a phase III study for US Food and Drug Administration review were matched with 133 eyes treated with LASIK by criteria of age (>18 years, <65 years), preoperative myopia (−1.00–−3.50 diopters [D]), astigmatism (≤1.00D), single treatment, and attempted full correction. Examinations were performed preoperatively and postoperatively at days one and seven and months one and three. Visual acuity and manifest refraction data were collected retrospectively. Visual function scores were assigned, and summarized results were compared. Uncorrected visual acuity was 20/20 or better at day 1 in 24% of eyes (20/82) after ICRS and in 55% of eyes (73/133) after LASIK, and at month three in 75% of eyes (58/77) after ICRS and in 67% of eyes (84/126) after LASIK. Spherical equivalent refraction at month three was within ±1.00D of intended correction in 99% of eyes (76/77) after ICRS and in 96% of eyes (121/126) after LASIK. Excellent visual function scores were noted at month three in 90% of eyes (69/77) after ICRS and in 78% of eyes (98/126) after LASIK. Patients treated with LASIK showed better uncorrected visual acuity immediately following surgery; however, beyond one month, patients treated with ICRS achieved better uncorrected visual acuity that continued to improve with time. Visual function scores indicate that ICRS eyes see at higher levels of uncorrected visual acuity than LASIK eyes do with the same refractive error. The authors conclude that the ICRS and LASIK were comparable in the correction of mild myopia.—Thomas J. Liesegang