Visual Acuity Improvement in Low, Moderate and High Myopia After Posterior-Chamber Phakic Implantable Collamer Lens Surgery in a Large Patient Cohort

Abstract

Purpose

To compare best-corrected visual acuity (BCVA) before and after implantable collamer lens (ICL) surgery in patients with low, moderate and high myopia.

Methods

A single-centre, prospective, registry-based study involving patients with myopia who received ICLs between October 2018 and August 2020. The study population was divided into three groups of subjects with low (from 0 to −6 D), moderate (−6 to −10 D) and high myopia (more than −10 D). We analysed uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent (SE), differences between BCVA pre- and 1-month postoperative, and line gain in BCVA 1 month after surgery.

Results

A total of 770 eyes belonging to 473 patients were surgically intervened during the study period, of which 692 eyes completed 1 month of postoperative follow-up and were included in the study population. At 1-month follow-up, 478 eyes (69%) achieved a BCVA of 20/20, 599 (87%) obtained 20/25 or better, and 663 (96%) had a BCVA of 20/40 or better. We identified a significant improvement in BCVA (baseline 0.15±0.2 logMAR vs follow-up 0.07±0.2 logMAR, p<0.0001) and a significant reduction in SE (baseline −9.23±4.1 D, vs follow-up −0.21±0.8 D, p<0.0001), with a significant relationship between preoperative SE and line gain (r = −0.46, p<0.0001). We identified a significantly higher line gain among eyes with higher degrees of myopia (low myopia 0.22±0.69 lines compared to moderate myopia 0.56±1.1 lines and high myopia 1.51±1.9 lines, p<0.0001). Notably, 99.6% of eyes with a high grade of myopia achieved improvement to a low degree (less than −6 D) at follow-up. The safety and efficacy indexes were 0.083±0.1 and −0.001±0.1, respectively.

Conclusion

In this large patient cohort, ICL surgery was related to a significant line gain in BCVA, particularly among eyes with higher degrees of myopia.

Keywords:

• myopia
• implantable collamer lens
• visual acuity
• phakic intraocular lens
• refractive surgery

Data Sharing Statement

The datasets analysed in the current study are available from the corresponding author upon reasonable request.

Ethics Approval and Consent to Participate

The study was conducted according to the tenets of the Declaration of Helsinki. This study was approved by the Institutional Review Board of the Instituto Zaldivar. Informed consent was obtained from all the patients prior to enrolment.

Author Contributions

All authors made substantial contributions to the conception and design, data acquisition, analysis and/or interpretation; took part in drafting the article or revising it critically for significant intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

Drs. Roger and Roberto Zaldivar are consultants for STAAR Surgical. The remaining authors have no proprietary or financial interest in the materials presented herein.

Additional information

Funding

This work was supported by STAAR Surgical.