Clinical Prediction of Excessive Vault After Implantable Collamer Lens Implantation Using Ciliary Body Morphology

PURPOSE: To determine the factors related to the ciliary body that are predictive of outcomes of excessive vault (> 1,000 mu m) after Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation. METHODS: In this retrospective case-control study, 27 eyes of 27 patients who presented with excessive vault (> 1,000 mu m) following implantation of an ICL V4c were matched in a 1:2 ratio with those who presented with a normal vault (250 to 1,000 mu m) on white-to-white distance, anterior chamber depth, and ICL size. The preoperative biometric parameters and clinical outcomes were compared between the two groups. The relationship between the postoperative vault and various variables was assessed by multiple linear regression analysis. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% CIs for excessive vault. RESULTS: The vault value 1 month postoperatively was associated with preoperative anterior chamber volume, iris-ciliary angle, and crystalline lens rise (P < .05). In the conditional regression logistic analysis, every 1 degrees reduction in iris-ciliary angle was associated with 4% increased odds of vault greater than 1,000 mu m (OR = 0.96; 95% CI = 0.93 to 0.99; P < .001) and the anteriorly positioned ciliary body was associated with an increased risk of excessive vault after ICL implantation (OR = 3.57; 95% CI = 1.67 to 7.63; P < .001). In the excessive vault group, 1 eye underwent the ICL extraction and 3 eyes had an ICL exchange for a smaller ICL. After the ICL exchange, the mean value of postoperative vault decreased from 1,525.67 +/- 468.22 to 810.33 +/- 254.92 mu m. CONCLUSIONS: Eyes with an anteriorly positioned ciliary body were associated with a higher rate of excessive vault after ICL implantation, so the size of the ICL may need to be adjusted in these patients. Assessment of ciliary body characteristics adds significant information to the prediction of excessive vault after surgery.