Investigators assessed whether soft multifocal contact lenses with a high add power could slow pediatric myopia progression.
Study design
The BLINK randomized clinical trial comprised 294 children aged 7 to 11 years with myopia between -0.75 D to -5.00 D and less than 1.00 D astigmatism at baseline. Participants were randomized 1:1:1 to either high add power, medium add power or single vision contact lenses and followed for 3 years. The primary outcome measure was the 3-year change in cycloplegic spherical equivalent autorefraction, as measured by the mean of 10 autorefraction readings. Four of 11 secondary endpoints were analyzed, including 3-year eye growth.
Outcomes
Of the 294 participants, 92% were included in final analyses. Adjusted 3-year myopia progression was -0.60 D for high add power, -0.89 D for medium add power, and -1.05 D for single-vision contact lenses. The difference in progression was largest between the high add power and single vision groups (0.46 D), followed by high add versus medium add power groups (0.30 D), and medium add versus single vision groups (0.16 D).
Adjusted mean eye growth was 0.42 mm for high add power, 0.58 mm for medium add power and 0.66 mm for single vision. The difference in eye growth was -0.23 mm for high add power versus single vision, -0.16 mm for high add versus medium add power, and -0.07 mm for medium add versus single vision groups.
Limitations
While there is a great worldwide need for safe and effective interventions to reduce progression to pathologic myopia, the clinical significance of this study's findings remains unclear. As Neil Bressler, MD, points out in the accompanying editorial, comparing a myopic progression of 1 D, for example, from -2 D to -3 D, over the course of 3 years for one individual without a high add contact lens versus a progression of 0.5 D, from -2 D to -2.50 D in the same individual by use of a high power add seems to have little clinical significance as this individual has mild myopia and is unlikely to have pathologic myopia (≥-6 D). Other potential results of clinic interest that remain to be reported might include whether there was any association between baseline myopia, age or both with the treatment effect.
Clinical significance
There are several current strategies for reducing myopia progression in children. Some studies have shown a potentially protective effect of time spent outdoors. Other interventions include the use of low-concentration (0.01% to 1%) atropine eye drops, orthokeratology and soft dual-focus contact lenses. While this study shows that there may be some short-term benefit to the use of soft, dual-focus contact lenses for myopic children, this trial does not show that soft multifocal contact lenses will prevent pathologic myopia with its vision-threatening features.
Furthermore, whether or not these observed effects will persist over longer follow-up periods remains to be seen. These issues must be addressed before dual-focus contact lenses become standard of care to reduce the risk of myopia progression.