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.

Reproducibility of the Magnitude of Lens Rotation Following Implantation of a Toric Intraocular Lens with Modified Haptics

“…Rotation data from this study were compared with the POC data reported previously by Vukich et al, for a prototype non-toric monofocal IOL with fiducial axis marks (Prototype 2) with the same haptic design ( Figure 1 ). 14 In brief, that study was a prospective, randomized, multicenter paired-eye study using a similar study protocol and the same objective photographic method for measuring IOL rotation. A total of 99 eyes were implanted with the Prototype 2 IOL at one study site in Asia Pacific and two study sites in Latin America.…”

“…15 It was designed to deliver improved rotational outcomes within the first week following implantation. The purpose of this study was to evaluate the reproducibility of postoperative IOL rotation of the TECNIS Toric II (Model ZCU) IOL compared to the prototype non-toric monofocal IOL with fiducial axis marks (Prototype 2), reported previously by Vukich et al 14 In addition, visual performance, residual astigmatism, and surgeon satisfaction with the TECNIS Toric II (Model ZCU) IOL were assessed. Insights into the appropriateness of comparing rotational stability results between subjects of different races and ethnicities were also gained.…”

“…In addition, both Prototypes showed ≤5° absolute rotation for all eyes at the 1 week visit, and no cases of ≥10° rotation at any time through 6 months postoperatively. 14 Because the overall geometry of Prototype 2 was the same as the TECNIS ® toric IOL (Model ZCT), that design was selected for commercialization under the brand name TECNIS Toric II 1-Piece IOL (Model ZCU). 14 …”

“… 14 Because the overall geometry of Prototype 2 was the same as the TECNIS ® toric IOL (Model ZCT), that design was selected for commercialization under the brand name TECNIS Toric II 1-Piece IOL (Model ZCU). 14 …”

Toric intraocular lenses: Evidence‐based use

“…Routine accuracy of axis placement is reported as within 5 0 of the intended axis. 69,70 Average of misalignment where the alignment axis is signed (positive for counter-clockwise from the intended axis and negative for clockwise) is close to zero with a mean absolute value of less than 5 0 . 71…”