Astigmatic axis affects visual acuity after refractive surgery

The axis of astigmatism has a small but definite effect on uncorrected distance vision in eyes that achieved emmetropic spherical equivalent after laser refractive surgery, according to a study.A retrospective cohort of 17,436 eyes of 8,718 patients who underwent LASIK or PRK at the Care-Vision Laser Centers in Tel Aviv, Israel, was divided into three groups according to the steep astigmatic axis: with-the rule (WTR), oblique and against-the-rule (ATR). The oblique group was further divided into oblique WTR and oblique ATR. Uncorrected distance visual acuity (UDVA) was compared among the three main groups and between the two oblique groups.