Paper title: Long-term Effect of Dual-focus Contact Lenses on Myopia Progression in Children: A 6-year Multicenter Clinical Trial
- CooperVision Inc., Pleasanton, California
- Ophthalmic Research Group, School of Optometry, Aston University, Aston Triangle, Birmingham, United Kingdom
- Centre for Ocular Research and Education, School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
- Department of Ophthalmology, National University Hospital, Singapore, Singapore
- Clinical and Experimental Optometry Research Lab, Centre of Physics, School of Sciences, University of Minho, Braga, Portugal
- Visioncare Research Ltd., Farnham, Surrey, United Kingdom
Date: March 2022
Reference: Optom Vis Sci. 2022 Mar 1;99(3):204-212. [Link to open access paper]
This study reported the six-year data from the MiSight 1 day clinical study - the longest of its kind on soft contact lens interventions for myopia. This follows on from the MiSight 1 day three-year randomized controlled trial, published in 2019. Here is a summary of the first part and second part of the study, where each part was for a duration of three years.
In the first three years (years 0-3) of the MiSight 1 day study, the randomized controlled trial saw children aged 8-12 years with myopia -0.75 to -4.00D and no more than -0.75DC of astigmatism fit with either MiSight 1 day or single vision (Proclear) CLs. The absolute myopia control effect was 0.73D (59%) and 0.32mm (52%) less myopia in the MiSight group after 3 years.
In the second three years (years 4-6) of the study, the single vision wearing children were switched into MiSight 1 day (T3 group = 3 years of treatment) and the MiSight kids continued (T6 group = 6 years of treatment). In the first three years, the T6 group's axial length grew 0.30mm compared to the T3's (control) groups 0.62mm. In the second three years, both groups showed statistically similar growth of 0.22mm for T6 and 0.18mm for T3. Across the three years, the T3 group's axial length grew by 0.81 ± 0.43mm in total, compared to only 0.49 ± 0.39mm total growth in the T6 group.
The study retention rate was 81% in first 3 years and 85% in the second three years. Acuity was better than 0.00 logMAR (6/6 or 20/20) at the dispensing and final visits, with no differences between the group who started wear at age 8-12 (T6) versus the group who started at age 11-16 (T3).
Other key findings included the following.
- Within the T6 group, 23% of eyes showed no clinically meaningful change in spherical equivalent refractive error (defined as −0.25 D or less) across the full 6 years of treatment, indicating stability of their refractive myopia.
- The treatment effect was proportional to pre-treatment growth rates, meaning faster-growing eyes demonstrated greater reduction in progression. Clinically, this emphasizes the value of treating fast progressors.
- Compliance with lens wear was very high, with average wearing time of 6.5 days a week and 13 hours per day. Wearing time increased slightly in the second part of the study.
- No contact lens related serious adverse events (corneal infections, microbial keratitis) or significant changes on biomicroscopy (eg. hypoxia) were recorded during the 6 year period.
What does this mean for my practice?
This study shows that while starting earlier (age 8-12) gives the greatest cumulative benefit in slowing axial elongation, starting later (age 11-16) has a beneficial impact as well, with these new-to-MiSight children showing the same progression rate as those who had been wearing MiSight for three years prior. In the second part of the study, 60% of the new-to-MiSight wearers were teenagers and all were switched from single vision contact lenses - with no difference in dropout rates to the first three years, indicating good acceptance. This means myopia control can be successfully commenced even into the teenage years.
This study also shows the benefit of treating fast progressors, with a proportional treatment effect; and that almost one-quarter of children wearing MiSight 1 day for six years showed refractive stability of their myopia, with less than -0.25D overall change in their refraction.
What do we still need to learn?
Title: Long-term Effect of Dual-focus Contact Lenses on Myopia Progression in Children: A 6-year Multicenter Clinical Trial
Authors: Paul Chamberlain, Arthur Bradley, Baskar Arumugam, David Hammond, John McNally, Nicola S Logan, Deborah Jones, Cheryl Ngo, Sofia C Peixoto-de-Matos, Chris Hunt, Graeme Young
Significance: Treatment of myopic children with a dual-focus soft contact lens (DFCL; MiSight 1 day) produced sustained slowing of myopia progression over a 6-year period. Significant slowing was also observed in children switched from a single vision control to treatment lenses (3 years in each lens).
Purpose: This study aimed to evaluate the effectiveness of DFCLs in sustaining slowed progression of juvenile-onset myopia over a 6-year treatment period and assess myopia progression in children who were switched to a DFCL at the end of year 3.
Methods: Part 1 was a 3-year clinical trial comparing DFCLs with a control contact lens (Proclear 1 day) at four investigational sites. In part 2, subjects completing part 1 were invited to continue for 3 additional years during which all children were treated with MiSight 1 day DFCLs (52 and 56 from the initially treated [T6] and control [T3] groups, respectively). Eighty-five subjects (45 [T3] and 40 [T6]) completed part 2. Cyclopleged spherical equivalent refractive errors (SEREs) and axial lengths (ALs) were monitored, and a linear mixed model was used to compare their adjusted change annually.
Results: Average ages at part 2 baseline were 13.2 ± 1.3 and 13.0 ± 1.5 years for the T6 and T3 groups, respectively. Slowed myopia progression in the T6 group observed during part 1 was sustained throughout part 2 (mean ± standard error of the mean: change from baseline SERE [in diopters], -0.52 ± 0.076 vs. -0.51 ± 0.076; change in AL [in millimeters], 0.28 ± 0.033 vs. 0.23 ± 0.033; both P > .05). Comparing progression rates in part 2 for the T6 and T3 groups, respectively, indicates that prior treatment does not influence efficacy (SERE, -0.51 ± 0.076 vs. -0.34 ± 0.077; AL, 0.23 ± 0.03 vs. 0.18 ± 0.03; both P > .05). Within-eye comparisons of AL growth revealed a 71% slowing for the T3 group (3 years older than part 1) and further revealed a small subset of eyes (10%) that did not respond to treatment.
Conclusions: Dual-focus soft contact lenses continue to slow the progression of myopia in children over a 6-year period revealing an accumulation of treatment effect. Eye growth of the initial control cohort with DFCL was slowed by 71% over the subsequent 3-year treatment period.
Dr Kate Gifford is a clinical optometrist, researcher, peer educator and professional leader from Brisbane, Australia, and a co-founder of Myopia Profile.
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.