Five-year outcomes of posterior chamber phakic implantable collamer lens implantation in high myopia, keratoconus, and post-keratoplasty eyes.

Abstract

Purpose: To report on a 5-year follow-up of Implantable Collamer Lenses (ICL) implantation and compare it to previously published iris-fixated phakic intraocular lenses (IF pIOLs).

Methods: We describe the refractive results and adverse events of 30 eyes in 18 patients with high myopia, keratoconus, or status post-keratoplasty (PKP), at one, two and five years after surgery.

Results: Efficacy and safety index were 0.94 and 1.04, respectively, at 5 years after surgery. Intraocular pressure (IOP) was significantly higher postoperatively (p = 0.005). The endothelial cell loss (EC loss) caused by the ICL implantation was found to be 3.82%, 5.03%, and 11.41%, at one-, two-, and five-years post-surgery. During a 5-year follow-up, 92% of eyes lost a higher percentage of endothelial cells (EC) than the expected physiological loss. Among eyes with >25% EC loss, all affected eyes at 2 years, and 80% at 5 years, had either keratoconus or history of keratoplasty prior to ICL implantation. Postoperative EC loss positively correlated with preoperative keratometry and negatively with preoperative pachymetry. Significant inverse relationship was found between baseline and postoperative anterior chamber angle (ACA) and EC loss. Postoperative vault (388 ± 159 μm) showed a negative correlation with endothelial cell density (ECD) in 5-year follow-up. There was no cataract formation at 5 years postoperatively.

Conclusion: Compared to the IF pIOLs, the V4c ICLs have similar frequency of postoperative cataract formation but appear to be safer for the endothelium. Therefore, they are likely more suitable for keratoconus and PKP patients. However, the risk of long term IOP elevation seems to be higher.