Purpose  To compare refractive performance of implantation of an iris-fixated phakic intraocular lens (PIOL) through a novel trapezoidal corneal and a scleral tunnel incision.
Methods  Sixty-nine eyes selected to undergo PIOL implantation were randomly assigned to 1 of 2 groups: 5.2-mm trapezoidal corneal incision (TCI), 34eyes; 5.2-mm scleral tunnel incision (STI), 35 eyes. Visual acuity, refraction, corneal astigmatism, tonometry and endothelial cell density were recorded preoperatively and postoperatively. Surgically induced astigmatism (SIA) was calculated using vector analysis.
Results  No intraoperative complications were noticed. One days after surgery, the quantity of cells in the anterior chamber were significantly lower in TCI group than in STI group (P=0.019). The percentage of eyes with uncorrected visual acuity (UCVA) of ≥20/25 was 41.2% for TCI and 17.1% for STI; the difference was statistically significant (P=0.03), but not thereafter. The mean corneal astigmatism was significantly lower in the TCI group than in the STI group (P=0.01) 3 months postoperatively and subsequently. No significant between-group difference in SIA was found during the follow-up. There was no significant difference in best corrected visual acuity and endothelial cell loss between groups postoperatively.
Conclusions  The TCI and STI techniques are comparable in terms of safety and induction of astigmatism for the rigid iris-fixated PIOL implantation. However, the TCI is easy to perform and provides a faster visual recovery and lower postoperative corneal astigmatism compared with the STI.