Assessing the astigmatism-reducing effect of toric intraocular lenses in eyes with low astigmatism: randomized masked bilateral comparison

Abstract

Purpose: To evaluate the astigmatism-reducing effect of toric intraocular lenses (IOLs) for low amounts of corneal astigmatism. Setting: Hanusch Hospital, Vienna, Austria. Design: Randomized, masked, controlled trial with bilateral comparison. Methods: Patients scheduled for bilateral cataract surgery and a corneal astigmatism in both eyes between 0.75 diopters (D) and 1.5 D were included in this study. The first eye was randomized to receive either a toric IOL or a nontoric IOL, and the contralateral eye received the other type of IOL. At the follow-up visits, optical biometry, corneal measurements with tomography and topography, autorefraction, subjective refraction, corrected and uncorrected distance visual acuity (CDVA/UDVA) with ETDRS charts and a questionnaire were performed. Results: 58 eyes were included in the study. Postoperative median UDVA was 0.00 (logMAR) in the toric eyes and 0.10 in the nontoric eyes (P = .03). The median CDVA was 0.00 in both groups (P = .60). Median residual astigmatism determined by subjective refraction and autorefraction in the toric eyes was 0.25 D and 0.50 D, respectively (P = .04), and 0.50 D and 1.00 D in the nontoric eyes, respectively (P < .001). Conclusions: The use of a toric IOL appears to be appropriate from a threshold value of approximately 0.75 D preoperative corneal astigmatism. Further studies in a larger patient population are needed to confirm these results.