Prediction Of Long-Term Changes In Vault Using Early Postoperative Vault In Eyes With Icl Implantation

Vault in eyes with Implantable Collamer Lens (ICL) implantation has been reported to gradually decrease in many mid- and long-term studies. This study aimed to analyze the long-term reduction of vault height over a 10-year follow-up in patients implanted with ICL V4c and to develop a novel model for predicting vault decay.

Nagoya Eye Clinic, Aichi, Japan.
A retrospective study was conducted on 47 eyes of 26 patients who underwent ICL V4c implantation and were followed up for 10 years. The predictive accuracy was evaluated up to 1 year postoperatively using a validation group that received the same lens implant.

Vault measurements were taken at postoperative 1 week, 1 month, 3 months, 6 months, 1 year, 3 years, 5 years, 8 years, and 10 years. Vault at 1 week postoperatively (vault(1W)) showed a proportional relationship with vault at each time point after 1 month, passing through the origin, with both high vault and low vault cases showing the same rate of decrease. Therefore, vault ratio, using vault(1W) as the denominator, was examined and estimated using an exponential predictive model.

Neither a single-component or two-component model adequately reproduced the data. However, a three-component exponential function was created for the predictive formula. The sum of the three components in this formula showed good curve fitting with the average measured vault values in the predictive group. Furthermore, no significant difference was found between the predicted vault values and the measured vault values at all time points up to 1 year postoperatively in the validation group.

Long-term changes in vault height in ICL V4c-implanted patients were successfully predicted from vault measurements taken 1 week postoperatively, regardless of early postoperative vault height. Vault decay consists of at least three exponential functions with different rate constants, and the proposed model demonstrated good agreement with the observed vault decay over time in the validation data.