Association between vault and its related factors following posterior chamber phakic implantable collamer lens V4c implantation: a meta-analysis

Objective  To systematically analyze the correlation between vault and its related factors following posterior chamber phakic implantable collamer lens (ICL) V4c implantation.

Methods  Literature on factors related to vault height following ICL V4c implantation published from January 2011 to August 2022 was searched through PubMed, Cochrane Library, Web of Science, Clinical Trials, China National Knowledge Network Infrastructure, VIP Network, Wanfang Data, China Biomedical Literature Database and China Clinical Trial Registry Database using the correlation coefficient method.This study complied with the Cochrane systematic review guidelines, and the study protocol was registered on the International Prospective Register of Systematic Reviews website.Stata 16.0 software was used to perform statistical analyses.

Results  Twenty-one studies with 1 245 patients (1 978 eyes) were included.Meta-analysis results showed ICL size, anterior chamber depth (ACD), horizontal corneal diameter, axial length, pupil diameter and anterior chamber volume were positively correlated with vault ( r=0.42, 0.40, 0.29, 0.20, 0.31, 0.31; all P<0.05). Age, postoperative angle-to-angle distance, central corneal thickness, lens thickness and crystalline lens rise (CLR) were negatively correlated with vault height ( r=-0.20, -0.35, -0.12, -0.34, -0.56; all P<0.05). Subgroup analysis revealed that the vault height measured by Pentacam was 490.20 μm, which was 99.10 μm lower than 589.30 μm measured by optical coherence tomography.The vault measured more than 6 months after surgery was 513.90 μm, which was 13.50 μm lower than 527.40 μm measured within 1 month postoperatively.

Conclusions  ICL size and ACD have a strong positive correlation with vault height, while CLR has a strong negative correlation with vault height.The vault height measured by Pentacam is lower than that measured by optical coherence tomography, and the vault height exhibits a gradual decline over time.