Determining vault size in implantable collamer lenses: preoperative anatomy and lens parameters

Session Details

Session Title: Posterior Chamber Phakic IOLs

Session Date/Time: Sunday 15/09/2019 | 14:00-16:00

Paper Time: 15:20

Venue: Free Paper Forum: Podium 3

First Author: : P.Serra SPAIN

Co Author(s): :    Á. Sánchez Trancón   S. Cerpa Manito   O. Torrado   A. Baptista                    

Abstract Details

Purpose:

Implantable Collamer Lens (ICL) requires a safety distance from the crystalline lens, namely the vault. On one hand, a reduced vault increases the risk of crystalline lens trauma and cataract. On the other hand, if the vault is too high may induce iridocorneal angle closure and increased iris pigment dispersion, putting the eye can at risk of developing ocular hypertension. This study aims to find out what are the patients’ preoperative and lens parameters relevant in determining a targeted vault.

Setting:

Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain

Methods:

This study is a retrospective case series of 360 eyes (1eye-1patient) operated between 2012- 2017, with implantation of myopic ICL (EVO-V4c, STAAR Surgical Co. Monrovia, CA, USA). Scheimpflug tomography was used for measuring the White-to-white (WTW), Central keratometry (CK) and Central corneal thickness (CCT). Anterior-segment optical coherence tomography (AS-OCT Visante) was applied for measuring the iridocorneal angle-to-angle (ATA), internal anterior chamber (ACQ), crystalline lens elevation (CLE), iridocorneal angle (ACA) and vault. The sample was divided into three lenses groups according to the lens implanted (12.6, 13.2 and 13.7mm). Vault predictors were identified from the above variables using stepwise multivariate regression.

Results:

Statistically significant differences between the three groups were found for the WTW, ATA, ACQ, KC, ACA, vault and age (p<0.0001). In general, bigger lenses were implanted in eyes with larger transverse sizes (WTW and ATA), deeper ACQ, flatter corneas, and larger ACA. Also, larger ICL diameters were associated with higher vaults. Multivariate regression analysis identified the lens size (12.6mm: β=-0.33; 13.7mm: β=0.42) , ATA (β=-0.42), and CLE (β=-0.25), ICL spherical equivalent (β=-0.22) and patients’ age (β=-0.12) as predictors of the vault size (adjusted R-square=0.34 p<0.001).

Conclusions:

The multivariate model found can explain about 34% of the variability in the vault. Here is proposed that the predictors affect the vault through different mechanisms, the ATA interacts with the size of the ICL by varying the amount of compression that the lens is exposed; the CLE occupies the sagittal depth produced by the lens; the ICL spherical equivalent informs that more negative lenses have deeper sagittal depths; the ICL size indicates that lenses with larger diameter have deeper sagittal depths and age since it is a parameter varying with the CLE.

Financial Disclosure:

is employed by a for profit company with an interest in the subject of the presentation