Evaluation of rotational stability of two toric intraocular lenses, Acrysof IQ Toric and Tecnis Toric, using new ToriCalc software

Introduction
Cataract surgery with artificial intraocular lens implantation is one of the most frequently performed operations in ophthalmology. A standard monofocal intraocular lens does not correct preoperative astigmatism; such patients benefit from correction with a toric lens. In order to preserve optical properties of the toric lens, it must remain in a stable position in the post-operative period, as any rotation reduces its optical performance.

Aim of the study
To evaluate functional results and to compare the spontaneous rotation of two models of toric intraocular lens¬es (IOLs) implanted during phacoemulsification in patients with preoperative corneal astigmatism.

Material and methods
Two groups of patients were evaluated after planned standard phacoemulsification surgery with implantation of a toric IOL. Patients who fulfilled the inclusion criteria and con¬sented to participate were randomly assigned to one of the groups. Based on the anterior segment photography the toric lens rotation was calculated with purpose-designed ToriCalc software.

Results
No statistically significant between-group differences in mean best corrected distance visual acuity (BCDVA) or uncor¬rected distance visual acuity (UCDVA) were found preoperatively or during the follow-up. In both groups a postoperative signifi¬cant increase in UCDVA and BCDVA was observed. The rotation of the toric IOL was similar and not significant in both groups (p > 0.05). Spherical and cylindrical residual refractive errors were significantly lower after the surgery in both groups.

Conclusions
Both examined IOLs offer excellent and similar rotational stability and very good functional results. The soft¬ware-guided postoperative evaluation of rotational stability of to¬ric IOLs is a good method of evaluating their position.