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The purpose of this Correction of Myopia Evaluation
Trial (COMET) was to evaluate the effect of progressive addition lenses (PALs)
compared with single vision lenses (SVLs) on the progression of juvenile-onset
myopia. Researchers enrolled 469 children, ages 6 to 11 years with myopia
between –1.25 and –4.50D spherical equivalent. The children were ethnically
diverse. They were randomly assigned to receive either PALs with a +2.00
addition or conventional spectacle treatment for myopia. All patients were
followed for 3 years. The outcome measure was progression of myopia, as
determined by auto-refraction after cycloplegia. The secondary outcome measure
was change in axial length of the eyes. Mean (+/- SE) 3-year increases in
myopia (spherical equivalent) were –1.28 +/- 0.06D in the PAL group and –1.48
+/- 0.06D in the conventional spectacle treatment for myopia group. The 3-year
difference in progression between the two groups was statistically significant.
The treatment effect was observed primarily in the first year. The number of
prescription changes differed significantly by treatment group only in the first
year. At 6 months, 17 percent of the PAL group versus 30 percent of the
conventional spectacle treatment for myopia group needed a prescription change;
at 1 year, 43 percent of the PAL group versus 59 percent of the conventional
spectacle treatment for myopia group required a prescription change. Mean
changes in axial length correlated with those in refractive error (r = 0.86 for
PAL and 0.89 for conventional spectacle treatment for myopia).
The authors concluded that the use of PALs compared with conventional spectacle
treatment for myopia group slowed the progression of myopia in COMET children by
a small, statistically significant amount only during the first year, and that
the size of the treatment effect remained similar and significant for the next 2
years. The results provide some support for the use of bifocals, PAL, or reading
glasses to slow the progression of myopia. A much greater response is
achieved with atropine.
SOURCE: Gwiazda J, Hyman L, Hussein M, et al. A
randomized clinical trial of progressive addition lenses versus single vision
lenses on the progression of myopia in children. J Invest Ophthalmol Vis
Sci 2003;44(4):1492-1500.
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