Background: The current study compared optical quality before and after implantation of a posterior chamber phakic intraocular lens with a central hole [V4c implantable collamer lens (ICL)] under bright and dark lighting conditions by means of the Optical Quality Analysis System™ (OQAS; Visiometrics, Terrassa, Spain).
Methods: This prospective study involved 91 eyes of 46 consecutive high myopia patients (15 males and 31 females, average spherical equivalent - 10.50 ± 0.33D) undergoing implantation of a V4c ICL. The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuities (PVAs; 100, 20, and 9%), under different lighting conditions, were measured before and 1 week, 1 month, and 3 months after surgery.
Results: All optical parameters showed significant improvements, at all time points, under dark condition after surgery. We observed no significant changes in PVA 9% at 1 week (mean value 0.539, P = 0.12) or 1 month after surgery (mean value 0.573, P = 0.08) under bright condition; but all other postoperative parameters improved significantly. Comparing the two lighting conditions, the OSI decreased more under dark conditions at 1 week (P = 0.02), 1 month (P = 0.004), and 3 months (P = 0.002), but there was no significant difference in any other parameter. In addition, patients were divided into super high myopia (group S, spherical equivalent greater than - 10 D) and high myopia (group H, spherical equivalent from - 6 D to - 10 D), the group S improved significantly more than group H in all parameters, under both bright and dark conditions.
Conclusions: V4c ICL implantation improved optical quality under both bright and dark lighting conditions, and had a better ability to reduce the extent of scattering in the dark. Furthermore, group S achieved greater improvement in visual quality, which should be considered by physicians before surgery.
Keywords: Implantable collamer lens with a central hole; Lighting condition; OQAS; Optical quality.