Correlation of change in V4c implantable Collamer lens vaulting and pupil diameter in different light conditions

To study the change in the vault of phakic Intraocular Lens (IOL) (pIOL) with RT view anterior segment optical coherence tomography (ASOCT) in different light conditions and define its relationship with the change in pupillary diameter.

Prospective Observational Study.

Thirty eyes of 15 myopic subjects were enrolled. The implantable Collamer lens (ICL) vault was measured in three light conditions: room light, scotopic, and photopic conditions. Pupillary diameter was recorded in three light conditions using ASOCT and ImageJ software. The primary outcome measure was the change in ICL vault from baseline (room light) to scotopic and photopic conditions, respectively.

The mean age of participants was 22.33 ± 3.1 years. V4c ICL implantation was done for a mean refractive error of -10.08 ± 4.0D. The mean ICL vault in room light, scotopic, and photopic conditions were 568.57 ± 215.83 µm, 567.47 ± 225.11 µm, and 418.4 ± 210.04 µm, respectively. As compared to room light, there was no significant change in the ICL vault in scotopic condition (P = 0.89), but it was significantly decreased in photopic (P < 0.0001) condition. On regression analysis of change in vault in relation to the change in pupillary diameter, it was found that in photopic condition with every 1 mm decrease in pupil diameter as measured with ImageJ and ASOCT, there was a decrease in vault of 59.51 µm and 56.19 µm, respectively.

ICL vault decreases consistently and significantly in photopic conditions; however, scotopic condition has an inconsistent and lesser effect.