AIM:To observe the early variation trend of the vault after phakic posterior chamber implantable collamer lens/toric implantable collamer lens(ICL/TICL V4c)implantation and analyze the related influencing factors.

METHODS:In this retrospective study, a total of 49 patients(98 eyes)who underwent ICL/TICL V4c implantation in the Lanzhou Huaxia Eye Hospital from October 2020 to March 2021 were enrolled. Preoperative ocular biometric parameters were collected, including spherical equivalent(SE), intraocular pressure, axial length, anterior chamber depth(ACD), lens thickness(LT), central corneal thickness, anterior chamber angle(ACA), anterior chamber volume(ACV), white to white corneal diameter(WTW), mean keratometry K1 and K2, and intraoperative implantation size of ICL. The vault was measured by anterior segment optical coherence tomography(AS-OCT)at 1, 3d, 1wk and 1mo after surgery. The patients were divided into insufficient vault group(<250μm, 12 eyes), normal vault group(250-750μm, 62 eyes)and excessive vault group(>750μm, 24 eyes)according to the vault at 1mo after surgery. The factors affecting the postoperative vault were analyzed.

RESULTS:The mean vault values at 1 and 3d, 1wk and 1mo after surgery were 591.05±293.44, 599.62±309.78, 592.22±301.49 and 586.69±285.63μm, respectively. There were significant differences in WTW, ACA, ACV, ACD, ICL size and LT at 1mo after surgery(all P<0.05). The regression equation of vault at 1mo after surgery was as follows: vault(μm)=-3142.19+388.25×WTW+10.40×ACA-301.63×LT(R=0.674, R²=0.454, adjusted R²=0.436). WTW had the greatest influence on vault at 1mo after surgery(β=0.47, P<0.001), followed by LT(β=-0.34, P<0.001)and ACA(β=0.17, P=0.047).

CONCLUSION:WTW, ACA and LT were the main factors that affected and predicted the vault at 1mo after ICL/TICL V4c implantation.