Laser in situ keratomileusus for mixed and simple myopic astigmatism with the Nidek EC-5000 laser

PURPOSE: To evaluate the visual and refractive results of laser in situ keratomileusis (LASIK) for mixed and simple myopic astigmatism using bitoric ablation. METHODS: A retrospective study was performed in 65 eyes of 38 consecutive patients to evaluate uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA) and cyclopegic and manifest refraction, before and 3 and 6 months after LASIK (Moria LSK-ONE microkeratome, Nidek EC-5000 excimer laser). RESULTS: At 3 and 6 months after LASIK, 40 eyes of 24 patients (64.5%) were available for follow-up examination. Mean age was 25.9 ± 6.6 years (range 18 to 43 yr). Mean preoperative manifest spherical equivalent refraction was -1.40 ± 0.80 D (range -3.80 to +0.50 D), mean preoperative cylinder was -3.30 ± 1.30 D (range - 1.00 to -6.00 D). At 6 months follow-up, mean manifest spherical equivalent refraction was +0.30 ± 0.46 D (range -0.38 to +1.88 D), mean cylinder was -0.73 ± 0.61 D (range -2.25 to 0 D). There was a 77.8% decrease in astigmatism magnitude. According to vector analysis, mean achieved vector magnitude was 80% of intended. Fifty percent (20 eyes) had a cylinder within ±0.50 D of emmetropia. Twenty-three eyes (57.5%) had a spherical component within ±0.50 D. Eighty-five percent (34 eyes) had postoperative UCVA of 20/40 or better. Ten percent (four eyes) lost two lines of Snellen BSCVA, whereas 35% (14 eyes) gained one or more lines. CONCLUSIONS: Bitoric LASIK with the Moria LSK-ONE microkeratome and Nidek EC-5000 excimer laser was effective and safe for the reduction of cylinder in mixed and simple myopic astigmatism. Moderate undercorrection of the cylinder was evident.