A randomized trial of the effect of single-vision vs. bifocal lenses on myopia progression in children with esophoria

Background: Bifocals have long been thought to reduce progression of childh ood myopia, However, this hypothesis has not been definitively evaluated, M ethods: We conducted a randomized clinical trial to test the hypothesis tha t bifocals slow myopia progression in children with near-point esophoria, E ighty-two myopic children were randomized to single-vision glasses (n = 40) or to bifocals with a +1.50 D add (n = 42) and were followed for 30 months . Refraction was measured by an automated refractor after cycloplegia, The primary outcome was myopia progression defined as the difference between th e spherical equivalent at baseline and at the 30-month examination, average d over both eyes. Results: Follow-up was incomplete for six children in the bifocal group and one child in the single-vision group, Among the children completing the 30 months of follow up, myopia progression (mean spherical equivalent of the two eyes) averaged 0.99 D for bifocals and 1.24 D for sin gle vision (unadjusted, p = 0.106; adjusted for age, p = 0.046), Treatment groups differed in their cumulative distributions (Kolmogorov-Smirnov proce dure, p = 0.031), Evidence for a treatment effect on growth in vitreous cha mber depth was similar (p = 0.046 by K.S.), Conclusion: Use of bifocals, in stead of single-vision grasses, by children with near-point esophoria seeme d to slow myopia progression to a slight degree.