Comprehensive Retrospective Analysis of EVO/EVO+ Implantable Collamer Lens: Evaluating Refractive Outcomes
Study At a Glance
NVISION’s Parkhurst NuVision practice reviewed 225 consecutive EVO ICL procedures performed over a six-month period, making it the largest single-practice analysis of EVO ICL outcomes ever published in the United States.
The one-month results were excellent. Among patients whose vision was correctable to 20/20 before surgery, every single one achieved 20/20 or better without glasses afterward. Overall, 94% of eyes landed within one diopter of their target prescription, the adjustment rate was under 5%, and no serious safety events were reported. The study’s value is in showing that the strong results seen in the FDA trial hold up in high-volume, everyday clinical practice.
Study Overview
This single-center retrospective study evaluated visual outcomes in 225 eyes of patients who underwent EVO or EVO+ Implantable Collamer Lens (ICL) implantation at Parkhurst NuVision in San Antonio, Texas — an NVISION partner practice — between April and October 2022. The EVO ICL is a posterior chamber phakic intraocular lens with a central port design, FDA-approved for the correction of moderate to high myopia with or without astigmatism in patients who are not candidates for laser vision correction.
The study analyzed patients within the FDA-approved age and refractive range, making it the largest single-center U.S. analysis of EVO/EVO+ ICL outcomes published to date. Four surgeons performed all procedures. Outcomes were measured at one month post-surgery and included uncorrected visual acuity (UCVA), refractive predictability, intraocular pressure, and postoperative complications.
NVISION physicians Dr. Gregory Parkhurst and Dr. Lauren Libfraind are co-authors. The study was IRB-approved through Advarra Institutional Review Board and conducted in accordance with the Declaration of Helsinki.
Key Findings: Visual Acuity
Visual acuity outcomes were the study’s primary endpoint — the main outcome the researchers set out to measure.
| Patient Group | Achieved 20/20 or Better UCVA | Achieved 20/25 or Better UCVA |
|---|---|---|
| Eyes correctable to 20/20 preoperatively | 95.1% | 99.3% |
| Eyes correctable to 20/25 preoperatively | 94.1% | 100% |
| All eyes (regardless of preoperative BCVA) | 84.4% | — |
| All eyes: 20/40 or better UCVA | — | 99.2% |
Among patients whose vision was correctable to 20/20 in either eye before surgery, 100% achieved 20/20 or better without correction at the one-month postoperative visit.
Key Findings: Refractive Predictability
Predictability refers to how closely the achieved correction matched the intended target refraction.
| Metric | Result |
|---|---|
| Eyes within ±0.50 D of target spherical equivalent | 75% |
| Eyes within ±1.00 D of target spherical equivalent | 94% |
| Toric ICLs implanted (astigmatism correction) | 51.5% of eyes |
| Overall postoperative adjustment rate | 4.8% (rotations, exchanges, or LVC enhancement) |
The most common ICL size implanted was 12.6 mm (56.4% of eyes), followed by 13.2 mm (27.5%) and 12.1 mm (15.1%). The mean cylindrical ICL power for toric lenses was 2.35 diopters.
Key Findings: Safety
The study found a favorable safety profile with a low rate of complications and secondary interventions.
Overall postoperative adjustment rate: 4.8% — among the 116 toric eyes, 21 (18.1%) showed residual cylinder greater than 1 diopter, resulting in 3 rotations, 3 explants, and 3 laser vision correction enhancements.
No serious adverse events were reported that would call into question the overall safety of the procedure. Intraocular pressure data were collected at all postoperative visits and remained within normal limits across the study population.
Study Context & Limitations
The authors note that this is the largest single-center U.S. study of EVO/EVO+ ICL commercial outcomes published to date, providing a real-world complement to the FDA multicenter clinical trial data. The primary limitations are the short follow-up period (one month), the retrospective design, and the absence of a comparator group. The authors call for future prospective studies to assess long-term outcomes and refine patient selection criteria.
Patient selection was consistent with standard clinical practice: subjects were excluded for prior ocular surgery, active autoimmune disease, diabetes, severe atopy, and pregnancy or nursing — reflecting the same criteria used in everyday candidate screening.