Correction of astigmatism using positive and negative cylinder programs with the Nidek EC-5000 excimer laser.

Abstract

BACKGROUND: The efficacy of a current program of positive cylinder treatment was evaluated and compared to a previous program of negative cylinder treatment. METHODS: The authors performed a comparative analysis of 123 eyes (72 patients) who underwent LASIK using the Nidek EC-5000 excimer laser with the formula developed by Chayet and the positive cylinder (71 eyes of 52 patients) and negative cylinder programs (52 eyes of 31 patients). RESULTS: A faster stabilization of correction and a marked reduction of stromal tissue ablated were obtained with the positive cylinder program than with the negative cylinder program. This was directly related to the amount of preoperative ametropia. CONCLUSION: The spectrum of ametropias that can be treated with LASIK is increased with the positive cylinder program because less tissue is ablated.