A new analysis from the BLINK2 Study provided evidence that discontinuing soft multifocal contact lenses for myopia control does not result in a rebound effect in axial elongation or myopia progression.
Previous research has shown that myopia progression can be slowed by spectacles, atropine, orthokeratology, soft multifocal contact lenses (MFCLs), and red light therapy, according to the investigators in this study. However, rebound effects have also been shown in many of these modalities.
“Previous atropine trials found accelerated eye growth after discontinuing treatment, especially with higher concentrations, and moderate rebound effects were observed after cessation of low-level red-light therapy,” David A. Bernsten, OD, PhD, of the University of Houston College of Optometry in Texas, and colleagues wrote in their JAMA Ophthalmology article. “An increase in axial eye growth greater than the rate of age-matched single-vision spectacle wearers was reported when 14-year-old children stopped orthokeratology treatment.”
“For any myopia control treatment to be truly beneficial,” they wrote, “the treatment effect must be retained after discontinuing treatment.”
The BLINK2 study followed participants who had completed the original BLINK Study, a randomized clinical trial that evaluated the effectiveness of multifocal contact lenses in slowing myopia progression.
The study enrolled 248 pediatric patients, aged 11 to 17 years at baseline, who had previously participated in the BLINK Study. During BLINK2, all participants wore high-add (+2.50 D) MFCLs for 2 years before switching to single-vision soft contact lenses for the final year. The primary objective was to assess whether discontinuing multifocal lenses led to a rebound effect in myopia progression and axial elongation by measuring axial length with optical biometry and tracking myopia progression with cycloplegic autorefraction.
After switching to single-vision lenses, axial elongation increased by 0.03 mm per year (95% CI = 0.01–0.05) and myopia progression increased by -0.17 D per year (95% CI = -0.22 – -0.12). These changes were within the expected age-related progression rates and were not dependent on the original treatment group assignment. Younger participants exhibited faster axial elongation and myopia progression than older participants, but again, all participants showed an age-appropriate progression rate after discontinuing multifocal lenses.
However, the investigators explained, “while the increase in axial elongation after discontinuing multifocal lenses was consistent across ages, the increase in refractive myopia progression was not.” The discrepancy between the effects on axial elongation and myopia progression could be a result of the crystalline lens’s decreasing ability to compensate for eye growth with age, but additional research is needed to understand how biometric factors such as lens power, lens position, and anterior chamber depth influence this relationship, the authors noted.
They also reported that the high-add multifocal treatment effect from BLINK was evident at the end of BLINK2, in which the original high-add multifocal group continued to have shorter eyes and less myopia than the original medium-add multifocal or single-vision groups. “This result is important as it differs from atropine studies that have reported faster than age-normal growth and loss of the treatment effect (rebound) after discontinuing treatment, with greater rebound as atropine concentration increases,” the researchers wrote.
Study limitations included the age of the participants. The mean age of participants was 17 when they discontinued MFCLs use, so it is unclear whether younger patients would have experienced a rebound effect. BLINK2 also did not include a single-vision control group and two axial length measurements were not performed with cycloplegia. Additional research is needed to confirm whether the lack of rebound result would apply to pediatric patients who wore MFCLs for less than 2 years, or whether patients switched from MFCLs to single-vision spectacles.
“Children who wore multifocal lenses longer had a larger treatment effect than those only treated in BLINK2,” the researchers concluded.
A full list of author disclosures can be found in the published research.
