| Budget Amount *help |
¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 2006: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2005: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Research Abstract |
Purpose : To assess the effect of progressive addition lenses (PAL) compared with single vision lenses (SVL) on myopia progression in Japanese children by a prospective, randomized, double-masked, crossover trial.
Methods : Ninety-two children fulfilling the entry criteria (ages 6-12 years, spherical equivalent refractive errors-1.13 to-5.95 D) randomly allocated to either 18 months of wearing PAL (near addition:+1.50 D) followed by 18 months of SVL (Group 1), or 18 months of wearing SVL followed by 18 months of wearing PAL (Group 2). Myopia progression was followed at 0, 18, and 36-month visits with cycloplegic auto refraction. Corneal refractive power, axial length, and baseline clinical characteristics were also evaluated.
Results : Eighty-six children (93%) completed both the treatment periods. A mixed model of two-way ANOVA showed that the treatment effect of PAL was highly significant (P = 0.0007), with an adjusted mean effect of 0.11 D/ year (95%CI: 0.05 to 0.17 D/year). The myopia progression was significantly smaller in Group 1 than in Group 2 (P = 0.0040), and the interaction between treatment (PAL or SVL) and treatment period (Group 1 or Group 2) was significant (P = 0.0223). Axial elongation found in the second period or the decrease in corneal refractive power did not significantly differ between the treatments.
Conclusions : Use of PAL slowed myopia progression, although the treatment effect was small, as previously reported in ethnically diverse or environmentally different children. The significant treatment-by-period interaction indicates that early application of PAL is probably more beneficial for these age and refraction ranges.
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