A quantitative assessment of the vault optimization along with the ocular bio-parameters and Implantable Collamer Lens sizing nomograms.

Abstract

Purpose: To quantify the effect of the significant ocular bio-parameters and the nomograms for an optimal Implantable Collamer Lens (ICL) vault.

Setting: Regional eye hospital.

Design: Retrospective.

Methods: Consecutive 103 patients (200 eyes) with implantation of ICL V4c were analyzed to find the important anterior eye parameters and the nomograms to achieve the optimal vaults (250 to 750 µm).

Results: The study found that anterior chamber width (ACW, β = 5.17, p = 0.0003), angle-to-angle (ATA, β = -3.1, p = 0.0084), and crystalline lens rise (β = 0.0044, p = 0.0007) are the significant parameters for predicting optimal vaults. For the ACW, a 10 µm increase from its mean (11.76 mm) would lead to 1.76 times higher odds for an optimized vault while holding all other variables constant. In contrast, a 100 µm increase from the ATA mean (11.63 mm) was associated with a 9.5% reduction in odds to achieve an optimal vault. CASIA2-NK or the Dougherty nomogram had similar higher odds to achieve an optimal vault than that by OCOS (odds ratio = 5.8, p = 0.0069; odds ratio = 3.3, p = 0.024). The magnitude of the difference between ACW and ATA was significantly associated with the odds of optimal vault.

Conclusions: The ACW and the ATA are both significant predictors for achieving an optimal vault; their size difference may bear significant value for ICL optimal vaults. CASIA2, along with its integrated formula, may be a stand-alone handy option for ICL size selection for the East Asian population.