Title: Measured and Predicted Axial Elongation in the MiSight 1 day Clinical Trial - 6 year results
Authors: Paul Chamberlain (1), David Hammond (1), Baskar Arumugam (1), Mark A. Bullimore (2)
- R&D, Coopervision Inc, Pleasanton, California, United States
- University of Houston, Houston, Texas, United States
Reference: ARVO 2021 Abstract
The ethical and practical concerns that arise through maintaining control groups without treatment are well established.1 This issue arose in a 6-year study that analyzed the efficacy of MiSight 1 day contact lenses. The results from the first 3 years of the randomized controlled trial study demonstrated the efficacy of MiSight in reducing myopic progression, and subsequently subjects in the control group were swapped into the treatment group (from single vision contact lens to MiSight). To ascertain the 3-to-6 year treatment effect, this research provides a comparison with an age matched 'virtual control group'.
The 'virtual control group' was a mathematical model previously proposed by Brennan et al in a meta-analysis of axial eye growth in control groups across 63 eligible studies. When compared to the MiSight data, the 'virtual control group' progression aligned with the observed control group progression in the first 3 years of the study. With this validation, the results in the 3-to-6 year phase was compared to the 'virtual control group' and an absolute axial control effect of 0.2mm over the three years was found. This indicates a treatment effect of just over 50% less axial growth in children commencing MiSight wear when older, at ages 11-15. The children who more MiSight for 6 years had a total 0.53mm less axial elongation than the 'virtual control', again representing just over a 50% total reduction in axial elongation.
What this means for your clinical practice: this research supports the long-term efficacy of MiSight 1 day for myopia control, over a total of six years of wear. Additionally, it demonstrates effectiveness in children commencing wear at 11-15 years of age. This means myopia control can be discussed and commenced in all children when deemed necessary, even into the early teenage years.
Purpose: A 6-year clinical trial randomized subjects to MiSight 1 day (Omafilcon A, dual focus design, CooperVision, Inc.; M1d) or Proclear 1 day (Omafilcon A, single vision, CooperVision, Inc.;P1D) contact lenses for the first three years during which M1d significantly slowed axial elongation Chamberlain et al. (2019). This analysis reports annual axial elongation and overall treatment effects over 6 years using a virtual control group.
Methods: Part 1: 144 myopic children (8-12 years of age) were randomized to wear either M1d or P1d. Part 2: After 3 years, the P1d wearers (n=56) were switched to M1d lenses (M1d-3) while the original treatment group (M1d-6; n=52) continued with M1d. All subjects were followed, unmasked, for an additional 3 years. In the absence of a concurrent control group, a virtual control group was created, based on the axial elongation model of Brennan et al. (AAO 2018). Estimated annual elongation (EAE) was calculated using the age and ethnicity of the P1d control cohort and used to quantify the myopia treatment effect of MiSight over the full 6 years.
Results: EAE for the virtual control group agrees well with the experimental control group during years 1-3. The EAE was 0.619 mm and 0.624 mm respectively, validating the virtual control group and its use for estimating EAE for an untreated control group for the final 3 years. The EAE for the virtual control group growth in years 4 to 6 was 0.395 mm. The year 4-6 total elongation in the M1d-3 and M1d-6 groups were 0.190 mm and 0.184 mm indicating 0.205 mm and 0.211 mm treatment effects. The treatment effect for the M1d-6 group when compared to the virtual control group over the full 6 years revealed a 0.529 mm reduction in axial eye growth (six year cumulative growth of 1.014 (control) – 0.485 mm (treatment).
Conclusions: Using a virtual control group, M1d substantially retards myopia by slowing axial elongation throughout six years of wear. This approach also shows effectiveness in newly treated older subjects in years 4-6.
Layman Abstract: Clinical studies into refractive error are usually longitudinal in nature, requiring tracking subjects’ changes over many years. The proven effectiveness of the MiSight 1 day soft contact lens and subsequent receival of FDA approval for controlling myopia have meant that it may be difficult to recruit control groups in multi-year myopia control studies for various reasons. Therefore, treatment switching paradigms with a short control phase or single arm intervention studies offer a practical approach for assessing the effectiveness of myopia control interventions over extended treatment periods. Furthermore, in recent times the mathematical modelling of historical control data is being used to develop virtual control groups in order to predict control response if no treatment was administered. This abstract presents longitudinal myopia control analysis over 6-years, for MiSight 1 day soft contact lens. The results indicate that the MiSight 1 day lens has a sustained myopia control effect throughout the 6-year duration.
Disclosures: Paul Chamberlain, CooperVision (Code E (Employment)); David Hammond, CooperVision (Code E (Employment)); Baskar Arumugam, CooperVision (Code E (Employment)); Mark A. Bullimore, Alcon (Code C (Consultant)), Apellis (Code C (Consultant)), Arctic Vision (Code C (Consultant)), Asclepix (Code C (Consultant)), CooperVision (Code C (Consultant)), CorneaGen (Code C (Consultant)), Essilor (Code C (Consultant)), EyeNovia (Code C (Consultant)), ForSight (Code C (Consultant)), Genentech (Code C (Consultant)), Johnson & Johnson Vision (Code C (Consultant)), Paragon Vision Sciences (Code C (Consultant)), Presbia (Code C (Consultant)), Sydnexis (Code C (Consultant)), Tear Film Innovations (Code C (Consultant)), Zeiss (Code C (Consultant))
Clare Maher is a clinical optometrist in Sydney, Australia, and a third year Doctor of Medicine student, with a keen interest in research analysis and scientific writing.