Prediction modelling for potential long-term MiSight efficacy

Paper title: Modelling Age Effects of Myopia Progression for the MiSight 1-day Clinical Trial

Authors: Arumugam, Baska;¹ Bradley, Arthur;¹ Hammond, David;¹ Chamberlain, Paul¹

1. Coopervision Inc, Pleasanton, California, United States

Date: June 2021

Reference: Baskar Arumugam, Arthur Bradley, David Hammond, Paul Chamberlain; Modelling Age Effects of Myopia Progression for the MiSight 1 day Clinical Trial. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2333

[Link to abstract]

 There is an ever-increasing prevalence of childhood myopia across the world and previous research has confirmed that younger children display faster myopia progression rates, meaning their age is an important factor when introducing a myopia control option.  Being able to curb the increase in a child’s short-sight is vital if we want to reduce their risk of future myopia-related eye health problems.

Coopervision conducted a 6-year study into the efficacy of their MiSight lens versus a control single vision lens in the same material and concluded the lens was able to provide a significant slowing effect on axial length elongation, thereby reducing the final refractive error.

The axial length data from the control and treatment groups from the study has now formed the basis of modelling to help predict the potential success with MiSight use compared to using single vision contact lenses.  Baskar Arumugam et al found the predicted average yearly increase in axial length for single vision lens wearers ranged from 0.30mm to 0.07mm, compared to the range of 0.16mm to 0.04mm for the MiSight wearers and an overall cumulative effect of 0.87mm was estimated for a child wearing MiSight from 8yrs old for 10years.  This is comparable to >2D of myopia control over this time.

This modelling for predicting the treatment effect is invaluable in helping practitioners assess the potential benefit of MiSight lenses for their young patients and as an aid for educating parents.  The data clearly demonstrates that the earlier a child begins treatment, the more chance there is of achieving significant reduction in their myopia.   This is especially true if they maintain wear during this period of ocular development.

Future research will tell us more about specific results anticipated for Asian children where they have been shown to experience faster progression earlier.

Title: Modelling Age Effects of Myopia Progression for the MiSight 1-day Clinical Trial

Authors: Baskar Arumugam, Arthur Bradley, David Hammond, Paul Chamberlain

Purpose: Age has a dominant impact on myopia progression rates within a population (Chua et al 2016).  Controlled clinical interventions are, however, routinely constrained by a limited age range of subjects and retaining control cohorts for long study durations is difficult.  This study aims to derive estimated annualised elongation (EAnE) models for both Proclear 1 day (omafilcon A, single vision, Coopervision, Inc.; P1d) and MiSight 1 day (omafilcon A, dual focus, Coopervision, Inc.; M1d) soft contact lens wearers over a 10 year age span from a 6-year randomised controlled clinical trial dataset.

Methods: Arumugam et al (AAO,2020) found that age also significantly affected axial progression rate in treated eyes, and after accounting for age, number of years in treatment had an insignificant effect, validating cross sectional analysis by age of the clinical trial data.  Annualised measured axial elongations (AMAE) were calculated across the full age range (8-18 years) irrespective of treatment years in the study using a cross sectional age analysis.  Control group (P1d) AMAE allowed optimisation of equation coefficients for the exponential decay function as previously reported by Brennan et al (AAO, 2018), using an iterative least squared error method.  The AMAE rates for subjects treated with the M1d lenses were also plotted by age and the EAnE model was derived based on best fits.

Results: The P1d and M1d datasets consisted of 350 and 888 annualised changes in axial length, respectively.  The following univariant (age in years) P1d and M1d EAnE models were derived:

P1d EAnE: ([-0.08135*e^{˄ -0.1(age)]}/-0.1) – 0.06295 R²:0.97 

M1d EAnE: -0.149 In (age) + 0.4659 R²: 0.96 

The P1d EAnE function exhibits a concordant correlation coefficient to the Brennan ‘white’ ethnicity equation (EAnE = 0.268*e ^{˄-0.144*[age-9.02}] R²:0.97).  A natural logarithm equation was found to the best fit the M1d dataset.  Using these EAnE models, the calculated cumulative axial elongation from 8 to 18 years of age for subjects wearing P1d and M1d lenses are predicted to be 1.84mm and 0.97mm respectively.

Conclusions: EAnE models predict, that if a myope commences M1d lens wear at 8 years of age and continues full time wear until 18, an average myopia control treatment effect of 0.87mm (>2D) would ensue.  The findings further support evidence that the greatest impact of eye growth will occur when treatment is started early and sustained longer.

[Link to abstract]