A Cochrane review [Abstract] 1 included 11 studies with a total of 1 939 subjects. Data was exctracted from 8 studies. Where more than one trial provided data for a comparison there was significant heterogeneity, therefore a narrative summary of the results is provided. For each study the results are presented in terms of the mean difference (MD) in final visual acuity measured using LogMAR notation.
At 12 months from treatment commencement the mean visual acuity in the spectacles only group was 0.31 (0.17 standard deviation (SD) compared to 0.42 (0.19 SD) in the no treatment group giving a MD of -0.11 (95% CI -0.22 to 0.00, borderline statistical significance, 1 study, n=42). The mean vision for the full treatment group (spectacles plus occlusion) was 0.22 (0.13 SD) and in the no treatment group it was 0.42 (0.19 SD); MD -0.20 (95% CI -0.30 to -0.10; 1 study, n=43).
3 studies compared spectacles plus occlusion with spectacles only and the MDs were: -0.09 (borderline statistical significance, 95% CI -0.18 to 0.00; n=42); -0.15 (not statistically significant 95% CI -0.32 to 0.02; n=35); and 0.01 (not statistically significant, 95% CI -0.08 to 0.10; n=82). 3 studies compared different occlusion regimes: 2 hours versus 6 hours for moderate amblyopia, MD 0.01 (not statistically significant, 95% CI -0.06 to 0.08; n=62); 6 hours versus full-time for severe amblyopia, MD 0.03 (not statistically significan, 95% CI -0.08 to 0.14; n=57); and 6 hours versus full-time occlusion, MD -0.12 (not statistically significant: 95% CI -0.27 to 0.03; n=24).
One trial looked at occlusion supplemented with near or distance activities: MD-0.03 (not statistically significant 95% CI -0.09 to 0.03). One trial looked at partial occlusion and glasses versus glasses only: MD -0.01 (not statistically significant: 95% CI -0.05 to 0.03).
Comment: The quality of evidence is downgraded by indirectness (results are based on subgroup analyses) and by imprecise results (limited study size for each comparison).
Primary/Secondary Keywords