Efficacy Comparison Between Toric Posterior Chamber Phakic IOL and Posterior Chamber Phakic IOL Plus Modified Steep Meridian Corneal Relaxing Incision for Moderate to High Astigmatism Corrections

Purpose: To compare posterior chamber phakic intraocular lens (Implantable Collamer Lens [STAAR Surgical]) (ICL) plus modified steep meridian corneal relaxing incision (MS-CRI) to toric posterior chamber phakic intraocular lens (Toric Implantable Collamer Lens [STAAR Surgical]) (TICL) implantation for the correction of moderate to high astigmatism. Methods: In this prospective, randomized clinical trial, patients with myopia who had moderate to high astigmatism (200 eyes) were enrolled and divided into TICL (n = 100) and MSCRI (n = 100) groups. All patients underwent examinations for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and subjective refraction before surgery and at the 1- and 6-month follow-up visits. Vector astigmatism analysis was evaluated using the Alpins method. Results: The mean UDVA and CDVA demonstrated significant improvement after surgery in both groups. During the 6-month follow-up, the MS-CRI group showed a slight regression tendency ( P < .001) and the TICL group was stable for the astigmatism correction ( P = .510). At 6 months postoperatively, the mean magnitudes of the surgically induced astigmatism were 1.46 ± 0.53 and 1.10 ± 0.48 diopters ( P < .001). The correction index of the TICL group was closer to 1 compared to that of the MS-CRI group (0.95 vs 0.76). Approximately 99% of eyes in the TICL group had angle of error within ±15°, whereas 89% eyes in the MS-CRI group were within that range. A significant relationship between the magnitudes of target induced astigmatism and correction index was noted in the MS-CRI group ( P < .001), but not in the TICL group ( P = .592). Conclusions: TICL implantation could achieve better visual outcomes for correcting moderate to high astigmatism compared to ICL implantation plus MS-CRI. [ J Refract Surg . 2023;39(8):539–545.]