Toric Implantable Collamer Lens In Low And Normal Vault: 5 Years Follow Up

This study aimed to analyze clinical results after implantation of a toric posterior chamber ICL (KS-AquaPORT™, STAAR Surgical Company, V4c and V5 models) in terms of visual and refractive outcomes, comparing low vault to normal vault patients, during a 5-year follow-up period.

Implantable collamer lenses (ICL) are a type of posterior chamber phakic intraocular lens. Generally, they are used for moderate to high degrees of refractive error or when corneal refractive surgery is contraindicated. Toric ICLs correct astigmatism and patients with a low postoperative vault have an increased risk of lens rotation, requiring additional surgery for lens repositioning.

This was a retrospective analytical study in which data was analyzed from patients operated with the implantation of toric ICL lenses at Hospital de Braga, between 2013 and 2018, with a minimum follow-up of 5 years. Patients were classified according to the vault measurement on postoperative day 1 into low vault (vault equal or lower than 250 microns) or normal vault (greater than 250 microns). Reviews were carried out at 1 month, 12 months, and 30 months (5 years) after surgery, analyzing visual acuity with and without optical correction, subjective refraction, vault measurement with anterior segment OCT, intraocular pressure, and endothelial cell count.

The study analyzed 98 eyes from 60 patients, divided into low vault (34) and normal vault groups (64). Both groups had similar average age and preoperative spherical equivalent. Preoperative astigmatism differed significantly between groups (-2.65±1.60 vs. -2.44±1.10 cylindric diopters, p=0.009). Efficacy and safety indices at 1 month post-surgery were 1.03±0.32 and 1.19±0.26 for the low vault group, and 1.16±0.32 and 1.24±0.30 for the normal vault group, respectively, remaining relatively stable over time. Residual astigmatism at 1 month post-surgery was -0.46±0.79 and -0.39±0.33 (low and normal vault, respectively), remaining stable up to 5 years. Lens repositioning occurred in 5.8% and 1.56% of low and normal vault groups respectively.

T-ICL shows good visual and refractive results in a 5-year follow-up, even in cases with low vault. There is good refractive rotational stability over time, regardless of the obtained vault. The efficacy and safety indices are very good and remain stable in the follow-up, regardless of the obtained vault.