Abstract
Purpose: :
To evaluate the influence of corneal incision location (at 12 o’clock or on the steepest axis) on astigmatism reducing effects of toric intraocular lens (IOL).
Methods: :
This prospective, comparative, consecutive case series included 30 eyes of 26 patients with preexisting astigmatism >1.0 diopter (D) who were undergoing cataract surgery using AcrySof Toric IOL (Alcon Laboratories Inc, Fort Worth, Texas, USA) implantation through 2.2 mm corneal incision. The incision was placed either at 12 o’clock (superior incision group, 15 eyes) or on the steepest axis (on-axis incision group, 15 eyes). Cylindrical power and axis placement to achieve emmetropia were calculated using the online toric IOL calculator program (AcrySof Toric Calculator). The logarithm of the minimum angle of resolution uncorrected visual acuity (logMAR UCVA), best-corrected visual acuity (logMAR BCVA), refractive error, and keratometric and refractive cylinder were measured preoperatively and at 1 month postoperatively. Axis rotation of the IOL was also measured. To investigate the changes in corneal astigmatic component, we converted pre- and postoperative astigmatism into a non-signed Astigmatic Power Vector (APV), which represents the magnitude of the astigmatic error, using Fourier analysis.
Results: :
In both the superior and on-axis incision groups, toric IOL implantation significantly reduced APV (p < 0.001). There was no statistical difference in logMAR UCVA (p = 0.780), logMAR BCVA (p = 0.713), degree of IOL rotation (p =0.549), and APV (p = 0.412) between two groups.
Conclusions: :
In cataract surgery with toric IOL implantation, the superior and on-axis corneal incisions similarly reduced pre-existing corneal astigmatism
Keywords: intraocular lens • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • refractive surgery: optical quality