Effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens

Abstract Background To investigate the effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens (ICL V4c). Methods This observational study recruited 62 eyes of 31 myopia patients underwent ICL V4c implantation. Anterior segment optical coherence tomography (AS-OCT) assessed the anterior chamber depth (ACD), ACD-ICL (distance from the corneal endothelium to anterior surface of the ICL V4c), vault (distance between the posterior ICL V4c surface and anterior crystalline lens surface), and crystalline lens tilt under various lighting conditions and accommodation relative to the corneal topographic axis at one year after ICL V4c implantation. Baseline was defined as the scotopic condition, which was also the non-accommodative stimulus condition. The ICL V4c tilt was analyzed using MATLAB. The significance level was set at P < 0.05. Results The ACD-ICL values were similar under various lighting conditions (P = 0.978) but decreased during accommodation (P < 0.001). The vault was significantly smaller under mesopic and photopic conditions than the baseline (P = 0.044 and P < 0.001, respectively) but remained unchanged during accommodation (P = 0.058). The inferotemporal proportion of ICL V4c (88.7%, 55 eyes) and crystalline lens (74.2%, 46 eyes) tilts were not significantly different (P = 0.063). Crystalline lens under various lighting conditions and accommodation exhibited similar tilts. The vertical tilt of ICL V4c was significantly larger under photopic conditions than the baseline (P = 0.038). The horizontal and total tilts were significantly decreased during accommodation (P = 0.043 and 0.013, respectively). Conclusions The axial position of ICL V4c in the anterior chamber was stable under various lighting conditions. Lighting conditions and accommodation may influence vertical, horizontal and total tilts of ICL V4c.