The Bermuda Triangle Of Icl Sizing: Low Myopia, Footplate Positioning, And Lens-Anatomy Interactions
Published 2026 - 44th Congress of the ESCRS
Reference: PP07.06 | Type: Free paper | DOI: 10.82333/g22j-w967
Authors: Mr Joseph Potter* 1 , Prof. Dan Reinstein 2 , Dr Timothy Archer 1 , Ms Ruchi Gupta 1
1London Vision Clinic,London,United Kingdom, 2London Vision Clinic,London,United Kingdom;Columbia University Medical Center,New York,United States;Sorbonne Université,Paris,France;Ulster University,Biomedical Science Research Institute,Coleraine,Ireland
Purpose
To quantify three sources of unpredictability in myopic ICL sizing: 1. Low myopia, 2. Postoperative footplate position, and 3. Lens-anatomy interactions and evaluate their contribution to large postoperative vault prediction errors.
Setting
Private Practice Academic Unit Reinstein Vision, London Vision Clinic, EuroEyes Group, UK
Methods
Retrospective analysis of 618 eyes undergoing EVO/EVO+ ICL sized with V3 of the Reinstein formula using VHFDU (Insight 100). (1) Low myopia: Eyes were stratified in 2.00 D bins by maximum meridian (−4.00 to −18.00 D); residual error variability (SD, IQR) calculated per bin. (2) Footplate position: In 481 eyes with postoperative VHFDU imaging, footplates were classified as ciliary body/zonular (CB) or sulcus (S); incidence and prediction error compared. (3) Lens–anatomy interaction: In eyes with known footplate position, lens “flip” (compressive buckling with upward angulation causing hyper-vault) was quantified. Sulcus predictions were adjusted by adding (CBIDLR − STSL); flip defined as achieved vault >200 µm above adjusted expected value.
Results
(1) Residual variability increased toward lower myopic powers. SD/IQR were 291/318 µm (-2.01 to -4.00 D), 284/339 (-4.01 to -6.00 D), 228/298 (-6.01 to -8.00 D), 178/211 (-8.01 to -10.00 D), 165/177 (-10.01 to -12.00 D), 168/201 (-12.01 to -14.00 D), 154/224 (-14.01 to -16.00 D), and 137/197 µm (-16.01 to -18.00 D). (2) Footplate position was ciliary body (CB) in 81% and sulcus (S) in 19%. Mean ± SD achieved vault was 553 ± 177 µm (CB) versus 831 ± 242 µm (S). Mean prediction bias was -42 ± 156 µm versus +204 ± 209 µm, demonstrating systematic hyper-vaulting with sulcus positioning. (3) Lens “flip” occurred in 3.7% overall (3.6% CB, 4.5% S).
Conclusions
Low myopic lenses demonstrated greater prediction variability, likely reflecting reduced compressive forces and increased sensitivity to anatomical variation in thinner lens designs. Sulcus footplate positioning occurred in nearly one-fifth of cases and was associated with systematic hyper-vaulting that current sizing formulas do not account for. Lens “flip” represents a further mechanical outlier phenomenon, producing marked hyper-vault beyond expected values. These findings highlight structural biomechanical limitations in contemporary ICL sizing strategies, which cannot anticipate footplate position or haptic buckling, and underscore the need for next-generation ICL sizing approaches which incorporate lens–anatomy interactions.