Abstract: Objective To explore the related factors affecting vault after implantable collamer lens implantation with central port. Design Retrospective case series. Participants 138 patients (276 eyes) who received ICL V4c implantation in Beijing Tongren Eye Center from January 2018 to November 2019. Methods Preoperative ocular biometric parameters were collected, including diopter, white to white (WTW), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (Angle), axial length (AL), lens thickness (LT) and ICL size. The vault was measured by anterior chamber-optical coherence tomography (AS-OCT) one week after surgery. Multiple stepwise regression analysis was used to determine the correlation between vault and preoperative biological parameters. The possible factors contributing to extremely low vault height (vault<250 μm) and extremely high Vault height (Vault > 1000 μm) were further analyzed. Main Outcome Measures Vault. Results The mean vault after the operation was 645±247 μm. The regression equation of arch height was obtained by using multiple step-by regression analysis: Vault (μm) =180.954×ACD (mm) +99.805×WTW (mm) -2517.5, and the adjusted r2 was 0.069. The ICL size was 127.9±3.8 mm, 127.3±3.6 mm, 130.2±2.8 mm and the ACD was 2.95±0.29 mm, 3.19±0.24 mm, 3.29±0.22 mm respectively, in low vault height groups, normal vault height group, and high vault height ( all P<0.05). There was no significant differences in age, SE, Angle, ACV, WTW, CCT, K1 and K2 among the three groups ( all P>0.05). Conclusion Vault is positively correlated with ACD and WTW, among which ACD has the greatest influence on vault. Moreover, LT was an important factor in both the low vault group and the high vault group. This suggests that non-age-related LT should be taken into consideration in the selection of ICL size in clinic.

Key words: implantable collamer lens implantation, vault, anterior chamber parameters, lens thickness