DIMS Myopia Spectacles Alter BV and Accommodation Parameters

US-based optometrists are hoping to have the opportunity to prescribe anti-myopia glasses in the near future. Research done outside the US is helping the community understand what to expect should the approval come through. Photo: Hoya Vision Care. Click image to enlarge.  Defocus incorporated multiple segment (DIMS) spectacles, currently only available outside the US, are a reliable intervention for myopia patients, but they could potentially affect binocular vision (BV) and accommodation. In a recent study, researchers investigated the effects of such lenses. They found that wearing DIMS lenses for two years resulted in changes in BV and accommodation while slowing myopia progression. The findings were reported in Journal of Optometry.A total of 23 Malay myopic children between the ages of seven and 12 were followed for 24 months. DIMS spectacle lenses were prescribed, and analyses were conducted at baseline, 12 and 24 months. Assessments included stereopsis, near point of convergence (NPC), phoria, positive/negative fusional vergence (PFV/NFV), amplitude of accommodation (AA), accommodative lag, positive/negative relative accommodation (PRA/NRA), and accommodative convergence to accommodation (AC/A) ratio. Visual acuity (VA), cycloplegic refraction (SER) and axial length (AL) were monitored. Regarding binocular vision and accommodation, significant changes were observed in NPC (receded by 2cm), exceeding the clinically significant threshold of >1cm based on test repeatability studies. This recession highlights the importance of annual monitoring visits in children wearing DIMS lenses in order to sustain BV function and visual comfort long-term, the authors noted.      Stereopsis improved by 10” after 12 months and remained stable. There were no significant changes in distance and near phoria, indicating that DIMS spectacle lenses provided stable binocular alignment.There was an increase in distance PFV in both break and recovery (break increased by eight, recovery increased by six). Clinically, this suggests an improvement in the ability to sustain binocular vision without diplopia and to regain fusion after diplopia.Although DIMS lenses primarily affect the peripheral retina, rapid eye movements may cause intermittent viewing through the lenslets, momentarily shifting the image to the fovea. In their paper, the authors explained that viewing through the lenslets probably induces exophoria, as the eyes tend to become more exophoric when binocularly viewing through plus lenses. “However, vergence adaptation helps stabilize phoria by increasing PFV, effectively managing the additional visual demand imposed by DIMS lenses and supporting sustained BV overtime,” the authors wrote. “This mechanism may explain the observed increase in PFV in children wearing DIMS lenses, though further research is needed to confirm the underlying adaptation processes.”Accommodative lag improved from +1.25D at baseline to +1.00D at 24 months, indicating a shift toward the normal range. Similarly, previous study reported a reduction in accommodative lag with comparable changes between DIMS and single-vision lenses, suggesting that myopic defocus did not influence accommodative lag.It’s been shown that age-related changes in the anatomy of the accommodative apparatus can influence the reduction in AA over time. In this study, monocular and binocular amplitude of accommodation decreased by 1.67D, which is consistent with a previous study reporting a reduction of 0.75D.Another important finding was a decline in myopia progression. The mean changes in SER and AL over 24 months of wearing DIMS spectacle lenses were -0.35D ±0.38D and 0.20mm ±0.22mm, respectively. The greater changes in SER during the first year may be due to the initial prescription of DIMS spectacle lenses, with the myopia control effect gradually taking effect, while more stabilized progression was observed in the second year. The authors noted that the initial enrollment was in 2021 during the COVID-19 pandemic, characterized by online learning and increased screen time which may have accelerated myopia progression.These findings are similar to previous studies on DIMS lenses in the Chinese population in Hong Kong, which found SER to be -0.38D ±0.06D after two years of wearing DIMS spectacle lenses, with AL elongation of 0.21mm ±0.02mm, showing that the effectiveness of myopia control treatments does not appear to be influenced by race.DIMS spectacle lenses demonstrated more favorable outcomes after two years of wear compared to other myopia control spectacle lenses. “After two years of wearing highly aspherical and slightly aspherical lenslets spectacle, greater SER changes of -0.66D and -1.04D were observed, with AL elongation of 0.34mm and 0.51mm, respectively,” the authors explained in their article. “Alongside changes in BV and accommodation, both distance and near VA improved with DIMS spectacle lenses, as observed in a previous study. This improvement appeared at 12 months and remained stable for 24 months.” The VA improvement was due to the “higher contrast generated by the DIMS design,” the authors contend, “which provides clear central vision and better visual performance when viewing through the central zone.”Click here for the journal source. Yahaya NA, Moha-A B, Najwa Norazman FN, et al. Assessment of binocular vision and accommodation in myopic children wearing defocus incorporated multiple segments (DIMS) spectacle lenses for 24 months. J Opt. May 17, 2025. [Epub ahead of print.]  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.