Evaluation of Intraocular Lens Rotational Stability in a Multicenter Clinical Trial

Abstract

Purpose: To evaluate the postoperative rotational stability of two prototype intraocular lens (IOL) designs (subsequently termed version 1 and version 2).

Patients and methods: A prospective, multicenter, randomized, paired-eye, 6-month study evaluated the version 1 and version 2 IOLs. Results were compared with a control IOL (TECNIS^® toric 1-piece monofocal IOL) evaluated in a separate, similarly designed study. Participants aged ≥22 years and scheduled to undergo bilateral cataract extraction were randomly assigned 1:1 to receive the version 1 or version 2 IOL in the first operative eye; the alternate test IOL was then implanted in the second operative eye.

Results: Mean absolute IOL rotation at postoperative week 1 was the primary effectiveness end point. Additional end points included the percentage of eyes with postoperative IOL rotation >5°/>10°, direction of lens rotation, surgeon-reported ease of IOL handling during implantation, and safety. At postoperative week 1, mean (±standard deviation) absolute IOL rotation was significantly lower for both version 1 and version 2 versus control (0.88° [±0.94] and 0.71° [±0.69] vs 2.24° [±3.21], respectively; both P < 0.001). For both study lenses, absolute rotation was <5° for all eyes at postoperative week 1, and no cases of rotation >10° were observed at any postoperative time point. From postoperative week 1 onward, version 2 had a statistically significant clockwise bias in the direction of rotation (P = 0.03); similar findings were observed for version 1. Surgeons reported acceptable ease of IOL handling during implantation for both version 1 and version 2. No device-related adverse events were reported.

Conclusion: Both the version 1 and version 2 IOLs, each with frosted, squared haptics, demonstrated improved postoperative rotational stability compared with a control lens without frosted haptics. Because version 2 had the same overall geometry as the current TECNIS toric IOL, this design was selected for commercialization.

Trial registration: German Clinical Trials Register, DRKS00015287.

Keywords: IOL rotation; astigmatism; cataract; surgery; toric IOL.