Optical Quality after Posterior Chamber Phakic Implantation of an Intraocular Lens with a Central Hole (V4c Implantable Collamer Lens) under Different Lighting Conditions

Abstract 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.