BASE-LINE CHARACTERISTICS IN THE MYOPIA PROGRESSION STUDY, A CLINICAL-TRIAL OF BIFOCALS TO SLOW MYOPIA PROGRESSION

Background. Retrospective studies have indicated that myopic children with nearpoint esophoria experienced slower myopia progression if they wore bifocal glasses rather than single-vision glasses. A small, 18-m onth clinical trial also supported that finding, but the results were not statistically significant. The Myopia Progression Study was funded by the National Eye Institute to test more rigorously the efficacy of bifocals, compared with single-vision glasses, in slowing myopia prog ression in children with nearpoint esophoria. A secondary objective of the study was to identify other variables that might influence the ra te of myopia progression. This report describes the design and methods of the Myopia Progression Study and the baseline characteristics of t he subjects. Methods. A 3-year, randomized clinical trial was initiate d. Subjects were children between 6 and 12 years of age who were myopi c (at least -0.50 D in each eye) and who demonstrated nearpoint esopho ria by the von Graefe technique. Results. Eighty-two children were enr olled. After blocking by gender and clinical site (two sites), subject s were randomly assigned to one of the two treatments: correction with single-vision spectacle lenses or correction with bifocal lenses havi ng a +1.50 D add in a flattop segment. The average degree of myopia at baseline was -2.31 D (SD = 1.31 D). Conclusion. This clinical trial c an be expected to determine the effectiveness of bifocal glasses in sl owing the progression of myopia in children with nearpoint esophoria.