Rotational Stability, Decentration, and Tilt of a New Hydrophobic Acrylic Intraocular Lens Platform

Abstract

To evaluate rotational stability, decentration and tilt of the monofocal intraocular lens (IOL) Nanex (NC1-SP; HOYA Surgical Optics). Prospective interventional case series. The study was performed at the Department of Ophthalmology, Medical University of Vienna. The study population comprised 130 eyes of 68 patients with age-related cataract who underwent cataract surgery with implantation of a Nanex IOL. Baseline image for rotational stability evaluation was obtained at the end of surgery (EoS) and compared to retroillumination images taken at 1 hour, 1 week, 1 month, and 6 months after surgery. Axis alignment was assessed using nonmovable landmarks on the sclera and the optic-haptic junctions of the IOL. Anterior segment OCT images were performed to evaluate decentration and tilt. The main outcome measure was absolute rotation from EoS to 6 months postoperatively. Median IOL rotation of all eyes from EoS to 6 months was 1.9° (interquartile range 0.1°-37.5°). Ten eyes (9.71%) rotated more than 5° and 2 eyes (1.94%), more than 10°. IOL rotation did not correlate with axial eye length (Spearman r=-0.042, P=.46), crystalline lens thickness (Spearman r=0.134, P=.19), and crystalline lens equatorial diameter (Spearman r=0.101, P=.325). IOL rotation positively correlated with anterior fibrosis severity (Spearman r=0.321, P=.002). Preoperative decentration (0.2 ± 0.12 mm) and tilt (5.7 ± 1.6°) did not change significantly after surgery (0.22 ± 0.12 mm and 5.62 ± 1.49°, respectively). The investigated IOL presented good rotational stability and low decentration and tilt values. Nevertheless, anterior capsule fibrosis development led to a higher tendency of IOL rotation after 1 week.