Posters

Important factors for a narrow postoperative angle after implantable collamer lenses surgery.

Poster Details

First Author: S.Cerpa Manito SPAIN

Co Author(s):    A. Sánchez Trancón   O. Torrado Sierra   A. Baptista   P. Serra           

Abstract Details

Purpose:

Intraocular Collamer lenses (ICL) are a widely used technique for the correction of moderate and high refractive errors. Implantation of a posterior chamber phakic lens leads to ocular anatomical changes, one is the reduction of the iridocorneal angle (ICA). This is produced by the protrusion of the ICL that pushes iris closer to the cornea. The long-term safety of this technique resides on the ability of the eye for maintaining a normal aqueous humour outflow, protecting the eye from increased intraocular pressure. This study aims to determine the factors associated with the presence of a narrow postoperative iridocorneal angle.

Setting:

Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain

Methods:

This retrospective case series analyzed 225 eyes (225 patients) implanted with myopic ICL (STAAR EVO-V4c, size 13.2 mm) between 2012 and 2017. Scheimpflug tomography was used for measuring the white-to-white (WTW), central keratometry (Kc) and central corneal thickness (CCT). Anterior-segment optical coherence tomography was applied for measuring the iridocorneal angle-to-angle (ATA), internal anterior chamber (ACQ), crystalline lens rise (CLR), iridocorneal angle (ICA) and vault. The eyes were divided into two groups depending on the postoperative ICA, ≤20 degrees (narrow) or >20 degrees (wide). A binary logistic regression (BLR) was used for determining the factors associated with a narrow postoperative-ICA.

Results:

The group with narrow postoperative-ICA (NG) compared to the group with wide postoperative-ICA (WG) had on average narrower preoperative ICA (36.9 vs 42.9 deg), higher vaults (867 vs 564 μm) and shallower ACQ (3.19 vs 3.30 mm). The BLR identified the preoperative-ICA, ACQ, and vault as contributing factors for a narrow postoperative-ICA (pseudo-R2=0.516). Wide preoperative-ICA and deeper ACQ are protective factors against NG (Preoperative-ICA (deg) OR: 0.871 and ACQ (mm) OR: 0.454). On the contrary, a higher vault is a risk factor for NG (Vault (μm ) OR: 1.006).

Conclusions:

The risk of narrow postoperative-ICA is mainly associated with two features, these are the patient's intrinsic preoperative anatomical biometry which includes the preoperative-ICA and ACQ and the surgery-induced anatomical change associated with the vault. These findings have implications at the time of deciding the ICL size to ensure a wide postoperative-ICA. Eyes presenting larger preoperative angles and deeper ACQ are more tolerable to an eventual oversize of the vault (i.e. lens sizes), whereas eyes with narrower the preoperative-ICA and ACQs need more restrict criteria for ICL sizing.

Financial Disclosure:

None