Using First Eye Early Vault to Determine ICL Size for the Second Eye: A Retrospective Analysis of Bilateral Phakic Intraocular Lens Implantation

Purpose: To evaluate the role of the first eye vault after the implantation of implantable collamer lens (ICL) V4c in selecting ICL size for the second eye and analyze the changing characteristics of the vault. Setting: Qingdao Eye Hospital of Shandong First Medical University Design: Retrospective case series Methods: In this retrospective study, 509 patients (1018 eyes) receiving bilateral ICL V4c implants were evaluated. Surgical management method was as follows: the vault was measured at 2 hours after the first eye surgery, and we selected ICL size for the second eye based on the vault of the first eye. The bilateral vault was measured and evaluated between different periods of follow-up. Results: The rate of ICL re-alignment or exchange due to abnormal vault was 1.47% (15/1018), with the second eye showing a significantly lower incidence (0.39%) compared to the first eye (2.55%)(P<0.01). Patients were categorized into four groups based on the vault value obtained at 2 hours postoperatively (baseline). There was significant difference in the value of vault decrease among the four groups at 1day, 1week, 1month, and 3months follow-up(all P<0.01). There was a significant positive correlation between the decrease in the vault and the baseline vault(all P < 0.01). Conclusion: Selecting the ICL size for the second eye based on the first eye's vault measurement 2 hours postoperatively can effectively minimize the need for further surgeries. Notably, eyes with a higher initial vault experienced a more pronounced decrease.