Influence Of Preoperative Pupil Diameter Under Different Lighting Conditions On Vault Of Implantable Collamer Lens.

To evaluate the influence of preoperative pupil diameters (PD) measured under different lighting conditions and the pupillary light response (PLR) on the postoperative vault and its change during the early postoperative period following Implantable Collamer Lens (ICL) implantation.

It is a prospective observational study.

This prospective observational study included 60 eyes of 30 patients who underwent ICL V4c implantation. Preoperative pupil diameters were measured under scotopic (0.04 lux), mesopic (4 lux), and photopic (40 lux) conditions using a dynamic pupillometer system (Pupillometer, DMK). Postoperative vault was assessed at 1 day, 1 week, 1 month, and 3 months using anterior optical coherence tomography (CASIA2 swept-source OCT, TOMEY). The correlations between preoperative pupil sizes and postoperative vault parameters were analyzed.

 A generalized reduction in vault was observed during the first postoperative week. However, significant positive correlations were found between the early vault change (vault at 1 week minus 1 day) and both the preoperative scotopic PD (r = 0.323, P = 0.012) and the PLR (r = 0.352, P = 0.006). This indicates that eyes with larger scotopic pupils and greater pupillary adjusting amplitude experienced significantly less initial vault reduction (greater early stability). Regarding the stabilized vault at 3 months, both preoperative scotopic PD (r = 0.291, P = 0.024) and photopic PD (r = 0.278, P = 0.032) demonstrated significant positive correlations with higher long-term vault outcomes. Mesopic PD showed no significant predictive value.

Preoperative pupillary dynamics, specifically the scotopic pupil diameter and pupillary light response, are novel contributing factors for predicting ICL vault behavior. Larger scotopic pupils and a wider range of pupillary adjustment are associated with less early vault reduction and a higher stabilized vault. Incorporating dynamic pupil metrics into preoperative evaluations may assist surgeons in refining ICL sizing and optimizing long-term safety.