Gurpal Virdi, MD

Publications

ICL sizing & vault research

My research is about fitting the right EVO / EVO+ ICL to an individual eye. The lens comes in four sizes and the same eye behaves very differently across them, so the question is which one fits that anatomy, not which one hits a number. Conventional sizing infers the answer from white-to-white corneal diameter and a single formula (OCOS, Reinstein, KS, NK, Parkhurst). My collaborators and I train image-based models on anterior-segment imaging and real surgical outcomes instead, which is what powers ICL Fit.

ICL Fit

ICL Fit is the AI agent this research is built into, and how I size an ICL. Published first as VAULT-OCT in the Journal of Cataract & Refractive Surgery, it predicts what each of the four available lens sizes would do in a specific eye from that eye's own anterior-segment imaging, trained on a dataset of 756 real EVO ICL surgical cases, and identifies the best fit.

Vault is an output, not the target. The 250 to 750 micron band usually quoted is a population average, and the same 400 microns can be comfortable in one anterior segment and too tight in another. The goal is the lens that fits that eye, not the lens that lands nearest a number taken from everybody else.

Peer-reviewed articles

Featured data: vault is dynamic

From Dynamic Changes in ICL Vault and Anterior Chamber Angle Under Varying Lighting Conditions (Clinical Ophthalmology, 2026), where we imaged 100 post-ICL eyes under scotopic, mesopic, and photopic lighting. The finding underpins how I approach sizing: vault is a physiologic range, not a fixed micron target, so the goal is best fit for the individual eye.

Box plot of ICL vault in microns across scotopic, mesopic, and photopic lighting, showing mean vault falling from about 496 to 394 microns as lighting brightens.
Vault by lighting. Mean vault dropped from 495.6 µm (dark) to 393.8 µm (bright): a ~100 µm swing in the same eye (p < 0.0001).
Box plot of anterior chamber angle in degrees across scotopic, mesopic, and photopic lighting, showing the angle widening in brighter light.
Angle by lighting. The anterior chamber angle widened from 27.2° to 29.7° under bright light; vault and angle track with pupil size.
Scatter plot showing eyes with higher mean vault also have greater vault variability across lighting.
Higher vaults vary more. Variability rose with mean vault (ρ = 0.395, p < 0.0001): the highest vaults are also the least stable.
Scatter plot showing only a weak relationship between ICL power and vault variability.
Power barely matters. ICL power had only a weak effect (ρ = −0.224); vault is driven by lens size, haptic position, and sulcus anatomy.

Conference presentations

Educational articles

More from this work: the research is applied in ICL Fit (AI ICL sizing) and IOL Reference; explained for patients at ICLSurgery.com/research; and listed in full on the CV.

Common questions

What is ICL Fit?

ICL Fit is an AI agent that identifies the best-fitting EVO ICL size for an individual eye from a preoperative anterior-segment OCT image. It was published as VAULT-OCT in the Journal of Cataract & Refractive Surgery, developed with collaborators at Parkhurst NuVision, and trained on real surgical outcomes rather than a single corneal-diameter formula.

Why does ICL vault matter?

Vault is the gap between the ICL and the eye's natural lens. Too little risks cataract, too much can crowd the angle and raise pressure, so it is worth measuring. But it is a number that follows from the lens you chose, not a target to aim at: the quoted 250 to 750 micron range is a population average, and the right clearance depends on that eye's chamber depth, angle and sulcus. ICL Fit works the other way round, predicting which size actually fits the anatomy.

How does AI improve ICL sizing?

Traditional sizing uses white-to-white and anterior-chamber-depth formulas. AI models such as VAULT and VAULT-OCT learn directly from anterior-segment images and real surgical outcomes, capturing sulcus and anatomy the formulas miss; the approach behind the ICL Fit sizing tool.

Can people with a shallow anterior chamber get an EVO ICL?

Often, yes. My research on eyes with anterior chamber depth under 3.0 mm found EVO ICL can be safe and effective for myopia in carefully sized, appropriately selected eyes, though candidacy always requires a full exam.