One-year follow-up of posterior chamber toric phakic intraocular lens implantation for moderate to high myopic astigmatism

Objective: To assess the 1-year clinical outcomes of toric Visian Implantable Collamer Lens (ICL; STAAR Surgical, Nidau, Switzerland) implantation for moderate to high myopic astigmatism.

Design: Prospective, observational case series.

Participants: Fifty-six eyes of 32 consecutive patients, with spherical equivalent errors of -4.00 to -17.25 diopters (D) and cylindrical errors of -0.75 to -4.00 D, who underwent toric ICL implantation.

Methods: Before and 1 week and 1, 3, 6, and 12 months after surgery, the safety, efficacy, predictability, stability, and adverse events of the surgery were assessed in eyes undergoing toric ICL implantation. Ocular higher-order aberrations (HOAs) and contrast sensitivity (CS) function also were evaluated before and 1 year after surgery.

Main outcome measures: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), safety index, efficacy index, predictability, stability, adverse events, HOAs, and CS function.

Results: The logarithm of the minimum angle of resolution (logMAR) UCVA and logMAR BSCVA were -0.11 (corresponding to Snellen equivalent 20/16) ± 0.12 and -0.19 (corresponding to 20/12.5) ± 0.08 1 year after surgery, respectively. The safety and efficacy indices were 1.17 ± 0.21 and 1.00 ± 0.29. At 1 year, 91% and 100% of the eyes were within 0.5 and 1.0 D, respectively, of the targeted correction. Manifest refraction changes of -0.07 ± 0.27 D occurred from 1 week to 1 year. For a 4-mm pupil, fourth-order aberrations were changed, not significantly, from 0.05 ± 0.02 μm before surgery to 0.06 ± 0.03 μm after surgery (P = 0.38, Wilcoxon signed-rank test). Similarly, for a 6-mm pupil, fourth-order aberrations were not significantly changed, merely from 0.20 ± 0.08 μm before surgery to 0.23 ± 0.11 μm after surgery (P = 0.15). The area under the log CS function was significantly increased from 1.41 ± 0.15 before surgery to 1.50 ± 0.13 after surgery (P < 0.001). No vision-threatening complications occurred during the observation period.

Conclusions: In the authors' experience, the toric ICL performed well in correcting moderate to high myopic astigmatism during a 1-year observation period, suggesting its viability as a surgical option for the treatment of such eyes.