A new study published in Scientific Reports offers evidence supporting the use of Defocus Incorporated Multiple Segments (DIMS) spectacle lenses for myopia control, with no adverse effects over the 6-year study period.
What is this DIMS technology?
DIMS technology has a central optical zone for correcting refractive error as well as multiple micro lenses that create constant myopic defocus surrounding the central zone.
A honeycomb pattern of +3.50D segments is distributed throughout the mid-periphery.
Now tell me about this study.
This trial originated with a 2-year, double-masked, randomized, controlled trial of DIMS spectacle lens wear in pediatric patients..
In the third year of that trial, the children in the control group were switched to DIMS spectacles, and at the conclusion of the third year, all patients were invited to participate in the follow-up study for the next three years.
The full 6-year trial included 90 total participants.
How were patients categorized?
Participants were split into four groups: Group 1 wore the DIMS spectacles for 6 years; Group 2 wore DIMS spectacles for 3.5 years before switching to single-vision (SV) spectacles; Group 3 began with SV lenses before switching to DIMS spectacles for years 3-6; and Group 4 wore SV lenses from years 0-2, DIMS spectacles for years 3-4.5, and SV lenses from years 4.5 onward.
What was being studied?
The study primarily tracked spherical equivalent refraction (SER) and axial length (AL) over 6 years.
Findings?
The study groups with extended DIMS wear (1 and 3) exhibited slower rates of myopic progression and axial elongation than those groups who discontinued the DIMS wear (2 and 4).
The 6-year study also enabled tracking of possible rebound effects after discontinued treatments, a common concern about myopia control methods.
For the two groups that discontinued DIMS wear, the mean myopia progression and axial elongation were 0.22D/year and 0.12 mm/year—an amount that the study authors describe as clinically insignificant compared to that of the patients’ age cohort.
Limitations?
After the initial 2-year period, the participants were allowed to self-select, meaning that this was not a randomized trial.
Additionally, the initial period of tracking and follow-up was interrupted by the COVID-19 pandemic, which delayed the follow-up periods and potentially increased the participant attrition rate.
Take away.
The primary goal of this study was to determine the efficacy of the DIMS lenses and any potential rebound effects. Each group showed positive results when it came to efficacy and experienced no adverse effects.
Expert opinions?
The authors noted that younger enrollees in the study (<8 years at the time of enrollment) had myopia relative peripheral refraction (RPR) at baseline and showed less response to the myopia control effects than older participants with hyperopic RPR.
They suggest that children with baseline myopic RPR might have received too much myopia defocus at the mid-periphery retina from the DIMS lens, resulting in the lower efficacy of myopia control in that specific age group.
Further,based on these findings, “there could be a cap on the amount of imposed myopic defocus that could slow eye growth and myopia progression.”