Choroidal thickening in response to DIMS spectacle lens wear

Title: Effect of Defocus Incorporated Multiple Segments (DIMS) lenses on choroidal thickness in schoolchildren

Authors: Rachel Ka-man Chun (1), Zhengji Liu (1), Wing Chun Tang (1), Dennis Yan-yin Tse (1,2), Carly Siu Yin Lam (1,2), Chi Ho To (1,2)

1. Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong
2. Centre for Eye and Vision Research Limited, Hong Kong, Hong Kong

Reference: ARVO 2021 abstract

This study investigated the effect of Defocus Incorporated Multiple Segments (DIMS) lenses on choroidal thickness in schoolchildren. The authors report children wearing DIMS lenses had a significantly thicker sub-foveal choroid after 1 week of wear by around 10 microns, which increased during the first 6 months to around 20 microns and was maintained across the two year study duration. There was a correlation between more choroidal thickening and less axial elongation at 2 years, but choroidal thickening only explained around 8% of the variation in axial length.  

What this means for your clinical practice: This extends the field of research into DIMS spectacles through exploring a potential mechanism for the myopia control effect. Whilst there's still a lot to learn about the choroid's short- and long-term response to defocus, and the link with myopia control efficacy, it could become a diagnostic clinical test in future.

Purpose: To investigate the effect of Defocus Incorporated Multiple Segments (DIMS) lenses on choroidal thickness in schoolchildren

Methods: 183 myopic Chinese schoolchildren aged from 8-13 years were recruited in a 2-year double-masked and randomised clinical trial. They were either treated with DIMS lenses (n=93) or single vision (SV) lenses (n=90) in a random allocation for 2 years. Baseline measurements including cycloplegic refraction, axial length and subfoveal choroidal thickness (SFChT) were collected before the lens wear. SFChT were obtained from Ocular Coherence Tomography (OCT) images acquired by Heidelberg Spectral Domain OCT. SFChT were measured at 1 week, 1, 3, 6 months post lens wear. Cycloplegic refraction, axial length and SFChT were monitored in a 6-month interval afterwards.

Results: SFChT significantly increased after 1 week of DIMS lens wear compared to those wearing SV lenses (mean change relative to baseline ± SD at 1 week; DIMS vs. SV; 6.57 ± 13.54 µm vs. -3.01 ± 10.70 µm; p < 0.001, repeated measure two-way ANOVA). The magnitude of the thickening increased in the first 6 months of DIMS lens wear. The choroidal thickening sustained during the 2-year lens wear (mean change relative to baseline ± SD at 24 months; DIMS vs. SV; 13.45 ± 26.06 µm vs. -9.54 ± 23.15 µm). The changes in SFChT at 1 week showed a significant negative correlation with the changes in axial length at 24 months (Pearson r = -0.2822, p < 0.001).

Conclusions: Schoolchildren with DIMS lens had a significant thicker choroid at subfoveal region after 1 week of lens wear. The magnitude of choroidal thickening maintained throughout the DIMS lens wear for 2 years. Our results demonstrated that the myopic control effect by incorporating defocus produced a long-term and sustained choroidal thickening.

Disclosures: Rachel Ka-man Chun, None; Zhengji Liu, None; Wing Chun Tang, None; Dennis Yan-yin Tse, The Hong Kong Polytechnic University (Code P (Patent)); Carly Siu Yin Lam, Hoya (Tokyo, Japan)  (Code F (Financial Support)), The Hong Kong Polytechnic University (Code P (Patent)); Chi Ho To, Hoya (Tokyo, Japan)  (Code F (Financial Support)), The Hong Kong Polytechnic University (Code P (Patent)), Vision Science and Technology Co Ltd (Code I (Personal Financial Interest))