The Bifocal Lenses in Nearsighted Kids 2 (BLINK2) study has revealed that the beneficial effects of multifocal contact lenses for myopia control in older teenagers are sustained even after the lenses are discontinued. The research, conducted by David A. Berntsen, OD, PhD, and colleagues from the University of Houston College of Optometry and The Ohio State University College of Optometry, indicates that myopia progression returns to age-expected rates without a loss of treatment effect.
Durability of Myopia Control
For any myopia control treatment to be considered truly effective, the treatment effect must persist after its discontinuation. Previous studies on atropine and orthokeratology have shown accelerated eye growth or rebound effects after stopping treatment. The BLINK2 study aimed to determine if similar effects occurred after discontinuing multifocal contact lenses.
BLINK2 Study Design and Results
The BLINK2 cohort study included children aged 11-17 years who had completed the BLINK Study randomized clinical trial. In BLINK2, participants wore high-add (+2.50 diopter [D]) multifocal soft contact lenses for two years, followed by single-vision soft contact lenses in the third year to assess for rebound effects. The primary outcomes measured were axial length and refractive error, assessed annually.
Of the 248 participants (59% female) in the BLINK2 study, 235 completed the study (median age at baseline, 15 years; range, 11-17 years). At baseline, the mean axial length was 25.2 ± 0.9 mm, and the mean spherical equivalent refractive error was -3.40 ± 1.40 D.
Following the switch from multifocal to single-vision contact lenses, axial elongation increased by 0.03 mm/year (95% CI, 0.01 to 0.05), and myopia progressed at a rate of -0.17 D annually (95% CI, -0.22 to -0.12). These changes were independent of the original BLINK treatment assignment (P = 0.81 and P = 0.57, respectively).
Differences in axial length and refractive error persisted throughout BLINK2 based on the original BLINK Study treatment assignment, with the high-add group maintaining shorter eyes and less myopia than the medium-add (+1.50 D) and single-vision groups.
Implications for Clinical Practice
The investigators concluded that discontinuing multifocal soft contact lenses in the late teenage years resulted in a return to age-expected axial growth, with no evidence of a loss of treatment effect or rebound. They advocate for fitting children with multifocal contact lenses for myopia control at a younger age and continuing treatment until the late teenage years when myopia progression naturally slows.
David Berntsen noted, "We found that one year after discontinuing treatment with high-add power soft multifocal contact lenses in older teenagers, myopia progression returns to normal with no loss of treatment benefit."
Myopia and Multifocal Lenses
Myopia, characterized by excessive eye growth, affects nearly 50% of the world's population and increases the risk of long-term eye health problems, including retinal detachment and glaucoma. Multifocal contact lenses correct myopic vision while simultaneously slowing myopia progression by slowing eye growth.
Designed with a bullseye-like structure, these lenses have a central portion that corrects nearsightedness and an outer portion that adds focusing power to bring peripheral light into focus in front of the retina, which animal studies suggest may slow eye growth.
Earlier Intervention, Lasting Impact
Jeffrey J. Walline, associate dean for research at the Ohio State University College of Optometry, emphasized the importance of early intervention, stating, "Our findings suggest that it’s a reasonable strategy to fit children with multifocal contact lenses for myopia control at a younger age and continue treatment until the late teenage years when myopia progression has slowed."
