Understanding the BLINK Clinical Trial Series and Myopia Prevention
Introduction to Myopia and Its Causes
Could the BLINK clinical trial series provide a solution for preventing nearsightedness, also known as myopia? Optometry researchers are making strides toward a potential remedy for poor eyesight. Many parents wonder what negative behaviors their tweens or teens might be engaging in that could be worsening their vision. Is it excessive studying at night, too much television, or prolonged gaming? Unfortunately, the issue is more complex than simply enforcing a “light-out” rule. Myopia typically begins to manifest around age eight and stabilizes by approximately 16 years. As children’s eyes grow, the underlying issue contributing to short-sightedness expands.
Potential Solutions for Myopia
Fortunately, ophthalmologists suggest that myopia progression might be slowed with the use of soft contact lenses. Investigative optometrists based in Houston, Texas, reported on January 16, 2025, in JAMA Ophthalmology, that adolescents who wore multifocal soft contact lenses for two years experienced a slowdown in myopia progression. When these teens switched to single vision lenses, their myopia advanced again, but at a normal age-appropriate rate rather than accelerating to compensate for the previous delay.
The BLINK Study Series
Overview of the BLINK Trials
The study, referred to as BLINK2, is a follow-up to the initial clinical trial named Bifocal Lenses in Nearsighted Kids, or BLINK. This randomized controlled trial aimed to test whether bifocal contact lenses could decelerate myopia progression in children. Published in 2020, the findings indicated that children around ten years old fitted with soft, bifocal contact lenses and who wore them as much as possible (approximately 11 hours a day) exhibited a slower myopia progression over three years compared to those wearing single vision lenses. Importantly, neither the children nor their parents, nor the optometrists conducting the vision tests, were aware of which type of lenses the children were using.
Study Methodology and Results
Researchers from Ohio State University and the University of Houston recruited 294 children aged seven to eleven, with myopia ranging from -0.75 D to -5.00 D, and no prior vision correction. The participants were randomly distributed into three groups: a control group fitted with single vision soft contact lenses, and two experimental groups fitted with multifocal soft lenses of +1.50 D and +2.50 D, respectively.
After three years, the results revealed that children wearing multifocal contact lenses had superior vision compared to those with single vision lenses. While the latter group saw an average progression of -1.05 D, the multifocal groups showed a lesser progression, with the medium strength lens group at -0.89 D and the high strength correction at -0.6 D. Notably, the effect was dose-dependent—the greater the correction, the more significant the impact on slowing myopia progression. However, researchers acknowledged that the differences were relatively small and might not hold clinical significance. Further studies extending over ten years could yield more substantial findings.
Long-Term Effects and Future Considerations
Impact on Eye Growth
In addition to slowing myopia, the researchers observed that multifocal contact lenses also inhibited axial growth of the eye. They hypothesized that the direction of this growth could influence vision changes, suggesting that these lenses might help by focusing some light in front of the retina.
The growth patterns of the eye are not perfectly symmetrical; those with astigmatism may have eyes shaped like American footballs or rugby balls. Even individuals without astigmatism typically do not possess perfectly spherical eyeballs. As children grow, their eyes develop unevenly, which can contribute to myopia. A possible solution lies in utilizing corrective lenses to maintain proper proportions during this growth phase.
Insights from the BLINK2 Study
The BLINK study indicated that children with myopia tend to experience more growth from front to back. This increased distance between the focal point and the retina exacerbates vision problems. The initial BLINK study found that starting multifocal contact lens wear around age ten slowed this axial growth. Over three years, eyes fitted with stronger multifocal lenses grew an average of 0.23 mm less than those wearing single vision lenses, with single vision lenses leading to a growth of 0.63 mm compared to 0.42 mm for high-powered multifocal lenses—a notable 30% difference.
Continuing Investigation: BLINK2 Outcomes
Assessing Long-Term Effects
Following the promising results of the BLINK study, researchers sought to determine the long-term effects of wearing multifocal lenses. They aimed to answer critical questions: If children discontinue lens wear, will their eyes undergo a growth spurt? Will they retain their vision benefits? Are there any long-term issues associated with lens use?
In a press release from the NIH, principal investigator David A. Berntsen, O.D., Ph.D., expressed concerns that discontinuing myopia-control contact lenses might lead to accelerated eye growth.
Findings from the Follow-Up Study
Researchers revisited the participants of the BLINK trial, now teenagers, and fitted 248 of them with multifocal lenses for an additional two years. After this period, their vision was re-evaluated, and they switched to single vision lenses for another twelve months.
The results indicated that all participants who wore multifocal lenses benefited significantly, with those who had used them during the initial study showing the most substantial advantages. While those who stopped wearing lenses in their late teens experienced a return to typical growth rates, their myopia progression remained slower than if they had never used multifocal lenses.
Conclusion: Implications for Myopia Management
Strategic Recommendations
Berntsen concluded that the findings suggest it is a sensible strategy to fit children with multifocal contact lenses for myopia control from a young age and to continue this treatment into their late teenage years when myopia progression tends to slow.
The question remains: could the simple intervention of bifocal lenses between ages seven and sixteen effectively prevent the progression of myopia? Further research will be essential to confirm these promising findings.
References
Contact lenses used to slow nearsightedness in youth have a lasting effect. National Institutes of Health (NIH). January 16, 2025. Accessed January 20, 2025. https://www.nih.gov/news-events/news-releases/contact-lenses-used-slow-nearsightedness-youth-have-lasting-effect
Berntsen DA, Tićak A, Orr DJ, et al. Axial Growth and Myopia Progression After Discontinuing Soft Multifocal Contact Lens Wear. JAMA Ophthalmology. Published online January 16, 2025. doi:10.1001/jamaophthalmol.2024.5885
Walline JJ, Walker MK, Mutti DO, et al. Effect of High Add Power, Medium Add Power, or Single-Vision Contact Lenses on Myopia Progression in Children: The BLINK Randomized Clinical Trial. JAMA. 2020;324(6):571. doi:10.1001/jama.2020.10834