The effect of implantable collamer Lens V4c on ocular biometric measurements and intraocular lens power calculation based on Pentacam-AXL and IOLMaster 500

BACKGROUND: To investigate the possible effect of implantable collamer lens (ICL) V4c on ocular biometric measurements by a new biometer Pentacam-AXL and partial coherence interferometry (PCI)-based IOLMaster 500 and intraocular lens power calculation using fourth-generation formula. METHODS: We retrospectively enrolled patients who underwent ICL (EVO-V4c, STAAR Surgical Co. Nidau, Switzerland) implantation surgery from September 2020 to November 2021. The Pentacam-AXL and IOLMaster 500 biometers were used to measure axial length (AL), anterior chamber depth (ACD), keratometry (K), white to white (WTW), and central corneal thickness (CCT) values before and at least 2 months after ICL V4c implantation. The IOL power was calculated using the Barrett Universal II formula. RESULTS: The study included 45 eyes in 28 patients. There was a significant increase in ALs (average 0.03 ± 0.07 mm, p = 0.01) and a significant decrease of ACDs (average 0.19 ± 0.17 mm, p < 0.001) based on Pentacam-AXL. Similar changes in ALs and ACDs were also found in IOLMaster 500. In addition, the difference in WTWs in the two devices and that of CCTs in Pentacam-AXL were statistically significant. However, the preoperative and postoperative K1 and K2 were separately comparable using either device. The IOL power calculated by the Barrett Universal II formula did not change significantly either by the software built in Pentacam-AXL or by manually putting the parameters of the IOLMaster 500 into the formula manually (p = 0.058, p = 0.675, respectively). CONCLUSIONS: Ocular parameters including ALs, ACDs, WTWs, and CCTs using a new Pentacam-AXL and standard PCI-based IOLMaster 500 changed significantly before and after the ICL V4c implantation, while IOL power prediction using the Barrett Universal II formula was little affected.