Myopia control efficacy through Emmetropic Progression Ratio:1-year of spectacle wear with cylindrical annular refractive elements (CARE)

Abstract

Purpose : To evaluate the performance of spectacle lenses (SPL) with cylindrical annular refractive elements (CARE) after 1-year of SPL wear with metrics based on age-related physiological eye growth.

Methods : Published data on annual axial length (AL) elongation for myopic and emmetropic eyes (>1000 eyes each, respectively, age 7-12 years, both Asian and Caucasian) were used to establish age-wise AL growth curves. Emmetropes had cycloplegic spherical equivalent refractive error (SE) of > -0.50D. The 1-year AL growth data for 144 Chinese children with myopia, SE -0.75D to -5.00D, aged 7-12 wearing SPL with CARE (n=72 eyes each with MyoCare (ZEISS) and MyoCare S (ZEISS) respectively, NCT05288335) was determined. The first method involved computing “Emmetropic Progression Ratio” (EPR) as (1-((progression with intervention-emmetropic progression)/(myopic progression-emmetropic progression)))*100% on a scale of 0-100% where 0% = AL growth equivalent to a myopic eye and 100% = AL growth equivalent to an emmetropic eye. In addition, EPR thresholds were used to categorize myopic eye growth under intervention into ‘similar to emmetropic’ (EPR ≥50%) or ‘equivalent to emmetropic’ AL growth (EPR ≥ 75%).

Results : In myopic eyes, AL growth decreased from 0.60±0.25mm/yr at 7yrs to 0.30±0.15mm/yr at 12yrs, whereas in emmetropes, AL growth was lower at 0.18±0.13mm/yr at 7yrs and 0.07±0.10/yr mm at 12yrs. For all ages, using method 1, 1-year AL growth with MyoCare and MyoCare S was lower than in myopes and closer to emmetropes with an overall EPR of 70% for MyoCare and 68% for MyoCare S (MyoCare 7yrs: 61% and 12yrs: 82%; MyoCare S 7yrs: 62% and 12yrs: 74%). Using method 2, 17% of eyes had AL growth similar to emmetropic eyes, while 53% of eyes showed AL growth equivalent to emmetropes with MyoCare, whereas 21% and 44% of eyes showed AL growth similar to or equivalent to emmetropic eyes using MyoCare S, respectively.

Conclusions : Both methods utilizing emmetropic AL growth demonstrate myopia control efficacy. EPR demonstrates that MyoCare and MyoCare S reduced myopic AL growth by an average of 70% and 68% compared to emmetropic eye growth. Seven of ten eyes wearing MyoCare or MyoCare S had eye growth similar to or equivalent to emmetropic eyes.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.