Software-based evaluation of toric IOL orientation in a multicenter clinical study.

PURPOSE: To evaluate the rotational stability of a new one-piece hydrophobic acrylic toric intraocular lens (IOL) using a custom-developed software for analysis of slit-lamp photographs.

METHODS

In a prospective, multicenter study, 174 eyes were implanted with the TECNIS Toric IOL (Abbott Medical Optics, Inc., Santa Ana, CA). A custom-developed software was used to analyze high-resolution slit-lamp photographs of 156 eyes taken at day 1 (baseline) and 1, 3, and 6 months postoperatively. The software uses iris and sclera landmarks to align the baseline image and later images for comparison. Validation of software was performed through repeated analyses of protractor images rotated from 0.1° to 10.0° and randomly selected photographs of 20 eyes.

RESULTS

Software validation showed precision (repeatability plus reproducibility variation) of 0.02° using protractor images and 2.22° using slit-lamp photographs. Good quality slit-lamp images and clear landmarks were necessary for precise measurements. At 6 months, 94.2% of eyes had 5° or less change in IOL orientation versus baseline; only 2 eyes (1.4%) had axis shift greater than 30°. Most eyes were within 5° or less of rotation between 1 and 3 months (92.9%) and 3 and 6 months (94.1%). Mean absolute axis change (± standard deviation) from 1 day to 6 months was 2.70° ± 5.51°.

CONCLUSIONS

The new custom software was precise and quick in analyzing slit-lamp photographs to determine postoperative toric IOL rotation.