Positive effect on myopic eyes continues after treatment with multifocal contact lenses
Following the switch from multifocal to single-vision contact lenses, axial elongation increased by 0.03 mm/year, and myopia progressed at a rate of −0.17 D annually after switching to single-vision lenses.
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The results of the recent Bifocal Lenses in Nearsighted Kids 2 (BLINK2)1 showed that the beneficial effects of multifocal contact lenses for myopia control in older teenagers are not lost after the patients discontinued their use. The myopia still progressed according to age-expected rates, according to David A. Berntsen, OD, PhD and colleagues. The research team is from the University of Houston College of Optometry, Houston, and The Ohio State University College of Optometry, Columbus.
They explained that for any myopia control treatment to be truly beneficial, the treatment effect must be retained after discontinuation of the treatment. Examples of treatments for which the beneficial treatment effects did not persist were atropine trials that found accelerated eye growth especially associated with higher concentrations after discontinuing treatment,2 and moderate rebound effects after low-level red-light therapy was stopped.3,4 In addition, increased axial eye growth greater than the rate of age-matched single-vision spectacle wearers occurred when 14-year-old children stopped orthokeratology treatment.5
BLINK2 Study
The BLINK2 cohort study included children with myopia ranging in age from aged 11-17 years who completed the BLINK Study randomized clinical trial. In the BLINK2 Study, the children wore high-add (+2.50 diopter [D]) multifocal soft contact lenses for 2 years and single-vision soft contact lenses during the third year to determine if rebound occurred. The main outcomes were the axial length and refractive error that were measured annually.
Of the 248 participants (59% female) in the BLINK2 study, 235 (median age at baseline, 15 years; range, 11-17 years) completed the study. At baseline in the BLINK2 study, the mean ± standard deviation axial length and spherical equivalent refractive error were 25.2 ± 0.9 mm and −3.40 ±1.40 D, respectively.
The investigators reported that following the switch from multifocal to single-vision contact lenses, axial elongation increased by 0.03 mm/year (95% confidence interval [CI], 0.01 to 0.05), and after switching to single-vision lenses, myopia progressed at a rate of −0.17 D annually (95% CI, −0.22 to −0.12). Both changes were independent of the original BLINK treatment assignment (P = 0.81 and P = 0.57, respectively).
Differences in axial length and refractive error continued throughout BLINK2 based on the BLINK Study treatment assignment with the original high-add group having shorter eyes and less myopia than the original medium-add (+1.50 D) and single-vision groups.
The investigators concluded, “This study found that discontinuation of 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 (rebound). Axial elongation and myopia progression after discontinuing multifocal lenses did not depend on treatment duration. Children who wore multifocal lenses longer had a larger treatment effect than those only treated in BLINK2.”
The investigators advocated fitting children with multifocal contact lenses for myopia control at a younger age and, when possible, continuing treatment until the late teenage years when myopia progression has slowed naturally.
