MAY 14, 2010
This prospective study randomized 131 Chinese Canadian children with myopia of at least 1 D and myopic progression of at least 0.50 D in the preceding year to treatment with single vision lenses (n = 41), 1.50-D executive bifocals (n = 48), or 1.50-D executive bifocals with a 3-prism diopters base-in prism in the near segment of each lens (n=46).
After 24 months, the treatment effect of bifocals (0.59 D) and prismatic bifocals (0.85 D) was significant (P < 0.001) and both bifocal groups had less axial elongation than the single vision lens group (P < 0.001). Myopic progression averaged -1.55 D for the single-vision lens group, -0.96 D for the bifocals group, and -0.70 D for the prismatic bifocals group, and axial length increased an average of 0.62 mm, 0.41 mm, and 0.41mm, respectively.
The authors concluded that bifocal lenses can moderately slow myopic progression in children with high rates of progression after 24 months. Since the prism effect was small and not reflected in axial length, prismatic bifocals should not be prescribed to all children with myopia.