Early clinical experience using custom excimer laser ablations to treat irregular astigmatism

Purpose: To assess the viability of custom excimer laser ablations for treating irregular astigmatism. Setting: Single-center prospective study of a new custom-ablation technique. Methods: Twelve patients received 15 custom ablations for irregular astigmatism resulting from keratoconus, penetrating keratoplasty for keratoconus, prior decentered laser in situ keratomileusis, or incisional refractive surgery. Follow-up ranged from 6 weeks to 14 months. initially, the laser beam was manually decentered; later, the Contoured Ablation Patterns (CAP) method (VISX, Inc.) was used to automatically decenter the ablation over the corneal elevation. Results: Results are presented in a case-by-case fashion. In the manual decentration group, the uncorrected visual acuity (UCVA) was 20/50 or better in 9 of 11 eyes (81.8%) and 20/40 or better in 7 eyes (63.6%). Surgery resolved or decreased visual symptoms when present. The best corrected visual acuity (BCVA) was maintained or improved in all eyes. Persistent less than or equal to grade 1 haze developed in the 2 patients (n = 3 eyes) treated for keratoconus. In the CAP group, the UCVA was between 20/40 and 20/80; the BCVA improved in 3 of 4 eyes (75.0%) and declined from 20/20 to 20/25 at 3 months in the remaining eye due to haze. The ablation produced some spherical flattening in both groups, resulting in induced hyperopia that was generally clinically insignificant. Conclusion: Early results of this experimental custom-ablation technique are promising. J Cataract Refract Surg 2000; 26:1442-1450 (C) 2000 ASCRS and ESCRS.