Implantable collamer lens sizing optimization based on the anterion AS-OCT biometric parameters

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Accurate sizing of Implantable Collamer Lenses (ICLs) is crucial for refractive outcomes.
• Current methods for ICL sizing may have limitations.
• Anterior segment optical coherence tomography (AS-OCT) provides detailed biometric data.

Purpose of the Study:

• To develop and validate regression formulas for optimal ICL sizing using Anterion AS-OCT data.
• To predict postoperative ICL vault based on biometric parameters.
• To compare the performance of the new formula with existing methods.

Main Methods:

• Retrospective case series involving 89 patients for development and 57 for validation.
• Development of the SN (Salouti-Nowroozzadeh) formula using multiple stepwise linear regression.
• Analysis of anterior chamber width (ACW), lens thickness, and anterior chamber volume (ACV).
• Prediction of ICL vault using a cubic non-linear model and the difference (Delta) between implanted and predicted ICL size.
• External validation using 73 prospective cases.

Main Results:

• The SN formula demonstrated an R-square of 0.602 for ICL size prediction.
• Delta was the sole independent predictor of postoperative ICL vault.
• A Delta of 0.3 mm yielded a 65% probability of optimal vault; 0.15 mm yielded 80%.
• The SN formula achieved 69.9% concordance with the STAAR nomogram.
• Mean absolute error for SN-predicted vault was 191 µm, with 63.7% of eyes within ±200 µm.

Conclusions:

• The developed SN regression formula provides acceptable predictions for ICL sizing.
• The formula's efficacy may differ across populations and devices.
• The study underscores the need for smaller ICL size increments to enhance postoperative results.