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 </=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.