Concerns about potential increases in astigmatism with certain myopia control lenses have been circulating among eye care professionals, but new data presented at the Netherlands Contact Lens Congress suggests that SightGlass Vision’s Diffusion Optics Technology (DOT) lenses do not share this risk. Studies analyzing data from both North American and Chinese children found no significant change in astigmatism rates after one year of wear with the DOT lenses, offering reassurance to practitioners and parents considering this approach to slowing the progression of nearsightedness.
Myopia, or nearsightedness, is a growing global health concern, particularly among children. Whereas traditional methods of correction address blurry vision, they don’t slow the underlying progression of the condition. Myopia control lenses aim to address this by altering how light focuses in the eye and several technologies are available. The research surrounding SightGlass DOT lenses comes after questions arose regarding potential astigmatic side effects associated with peripheral defocus technology, used in lenses from MyoVision (Zeiss) and Essilor Stellest (EssilorLuxottica).
DOT Lenses Utilize Contrast Modulation
Unlike peripheral defocus lenses, which induce positive power in the lenses, SightGlass DOT lenses work through a different mechanism: contrast modulation. This difference is key, according to researchers. “With DOT lenses, we just reduce the contrast slightly compared to peripheral defocus,” explained David Webley, BSc, MCOptom, FBCLA, senior director of clinical, medical and professional affairs at SightGlass Vision. “we could theorize that, because the power is consistent across the lens, there is unlikely to be any change within the astigmatic correction, and that might not be the same in a peripheral defocus lens.”
The analysis included data from two clinical trials: the CYPRESS study in North America (173 eyes, ages 6-10 years) and the CATHAY study in China (182 eyes, ages 6-13 years). Researchers compared right eye refractive data between groups wearing the DOT lenses and control lenses at baseline and after 12 months. The results indicated that neither the North American nor the Chinese data showed a significant change in astigmatism rates. Specifically, in the North American study, the percentage of eyes with astigmatism rose slightly from 87% to 92%, while in the Chinese study, it decreased from 91% to 88%.
Efficacy Consistent Across Populations
Beyond the astigmatism findings, another study presented at the conference examined the efficacy of SightGlass DOT lenses in North American and Chinese children, again utilizing the CYPRESS and CATHAY datasets. This research focused on axial length and cycloplegic spherical equivalent refraction – key measurements in myopia progression. The results demonstrated that children wearing DOT lenses experienced slower progression of both axial length and cycloplegic spherical equivalent refraction compared to control groups.
Axial length slowed by –0.15 ± 0.03 mm among North American children and –0.29 mm ± 0.04 mm among Chinese children. Cycloplegic spherical equivalent refraction slowed by 0.34 ± 0.07 D among North American children and 0.54 ± 0.09 D among Chinese children. “There is a consistency of efficacy across diverse populations,” noted Fabio Carta, DipOptom, FBCLA, director of professional affairs for EMEA & Canada at SightGlass Vision. “If you see other clinical trials with other products in the same myopia field, you can see differences between different populations. So, it was something new.”
Webley cautioned that further research is needed. “It’s important that it’s just one study, and I don’t think we can conclude very clearly that peripheral defocus lenses increase astigmatism,” he said. But, he acknowledged the growing concern among practitioners and emphasized that, “If you’re concerned by a patient whose astigmatism is seen to be increasing with their myopia control, we can clearly say there isn’t any link between DOT and astigmatism development.”
As myopia control continues to evolve, understanding the nuances of different technologies and their potential side effects is crucial for informed clinical decision-making. The findings from these studies offer valuable data for eye care professionals as they navigate the best options for their patients. Further long-term studies will be important to continue monitoring the effects of DOT lenses and other myopia control methods.
Disclaimer: This article provides informational content and should not be considered medical advice. Always consult with a qualified eye care professional for diagnosis and treatment of any eye condition.
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