Nearly 10 years of observational follow-up suggested sustained axial-length slowing, although refractive findings were less consistent and comparisons relied on statistical modeling.
To evaluate the long-term effects of Defocus Incorporated Multiple Segments (DIMS) spectacle lenses on axial elongation and myopia progression in young adults.
Approach:
Study Design: Observational follow-up of a prior randomized clinical trial cohort involving 60 young adults who previously participated in a DIMS lens trial.
Participants: Original trial enrolled children aged 8 to 13 years with myopia, astigmatism, and anisometropia, with a final analysis of 60 participants followed for a mean of 9.4 years.
Statistical Analysis: Linear mixed-effects models were used to assess changes in axial length and spherical equivalent refraction, with bootstrapping for cumulative outcomes.
Key Findings:
Continuous DIMS wear was associated with a 65% reduction in cumulative axial elongation compared to single-vision wear.
The axial-length effect was more pronounced before age 18 years.
Cumulative myopia progression with DIMS wear was estimated to be less than with single-vision wear, but the main effect was not statistically significant.
Interpretation:
The study indicates that DIMS lenses may slow axial elongation in myopic individuals, particularly in younger ages, although findings on myopia progression are less clear due to high residual noise in measurements.
Limitations:
The study was observational and lacked a contemporaneous untreated control group.
Attrition may have introduced survivor bias.
Reduced sample size limited statistical power for subgroup analyses.
Conclusion:
The findings highlight the need for cumulative metrics in evaluating long-term treatment success.
