Theoretical Analysis of the Effect of Pupil Size, Initial Myopic Level, and Optical Zone on Quality of Vision After Corneal Refractive Surgery

PURPOSE: To analyze the theoretical effect that pupil size, optical zone, and initial myopic level have on the final retinal image after corneal refractive surgery. METHODS: A schematic myopic eye model corrected by the Munnerlyn formula was used to analyze the optical quality of the final retinal image. Root-mean-square radius spot and modulation transfer function were calculated by ray tracing to evaluate retinal image quality. RESULTS: Pupil size had a negative effect on the retinal image only when it was greater than the diameter of the optical zone. In addition, the greater the initial myopic level, the more the pupil size affected image quality. Thus, a clear dependence exists between the initial myopic level and effect that the pupil size can have on the retinal image after laser refractive surgery. CONCLUSIONS: Pupil size may be a risk factor for night vision disturbances, but only when it is larger than the theoretical optical zones utilized in this study. Its effect depends not only on the optical zone size, but also on the initial myopic level. Therefore, this relationship should be taken into account during patient selection for refractive surgery. [J Refract Surg. 2012; 28(12):901-905.] doi:10.3928/1081597X-20121106-01