ABSTRACT
OBJECTIVE: To assess the safety, efficacy, predictability, stability, and changes in cylindrical degree and axis after iris recognize-guided LASIK with the Zyoptix 4.01 System for the correction of myopic astigmatism. METHODS: The present study was a prospective, nonrandomized, self-controlled trial. Iris recognize-guided LASIK with the Zyoptix 4.01 System (Bausch & Lomb) was performed in 97 patients (183 eyes) with myopic astigmatism in a 6-month trial. Patients were divided into 3 group according to the pre-operative cylindrical degree: Group 1, -0.50 to -1.00D, 79 eyes; Group 2, -1.25 to -2.00D, 70 eyes; Group 3, 2.00 to 4.00D, 34 eyes. They were also grouped by preoperative astigmatism axis: Group A, with the rule (WTR) astigmatism, 126 eyes; Group B, against the rule (ATR), 34 eyes; Group C, oblique axis astigmatism, 23 eyes. After a Hansatome microkeratome cut, iris recognized wavefront-based excimer ablation (Zyoptix 100) was performed. The degree and axis of astigmatism pre-operative and at various times post-operatively (1 day, 1 month, 3 month and 6 months) were analyzed and compared. RESULTS: At 6 month post-operatively, uncorrected visual acuity (VA) was 1.0 or better in 92.3% of the eyes, and 0.5 or better in all eyes. No eye lost > or = 1 lines of best spectacle-corrected VA (BSCVA) at 6 month post-operatively; 60 eyes gained 1 line of BSCVA, and 22 eyes gained 2 lines. The cylindrical degree of astigmatism decreased from (-1.54 +/- 0.65) D of pre-operation to (-0.26 +/- 0.25) D (6 month, post-operatively), the difference between these two groups was statistically significant. The uncorrected VA (UCVA) and the degree of astigmatism returned to normal in the first week and tended to be stable after 1 month. Six months after the operation, WTR astigmatism decreased from106 eyes (per-operation) to 45 eyes (post-operation). ATR astigmatism decreased from 43 eyes (per-operation) to 31 eyes (post-operation). Oblique astigmatism increased from 34 to 38 eyes. Sixty-nine eyes became non-astigmatism 6 months after the operation. CONCLUSION: Iris recognize-guided LASIK using Zyoptix is an effective and safe procedure for the treatment of myopic astigmatism.
