Six RCTs were included in the review (n=207 patients, range 12 to 61); four studies were considered to be of high quality. Duration of follow-up ranged from four to 24 months, but for most studies was six months or less. Funnel plots indicated the presence of publication bias
Visual acuity: Compared with placebo or no treatment, intravitreal triamcinolone acetonide injection yielded significantly greater improvement in visual acuity (measured in logarithm of the minimum angle of resolution units) at three months (WMD -0.10, 95% CI -0.20 to 0.00; four trials) but did not differ significantly at six months (WMD -0.05, 95% CI -0.15 to 0.05; four trials). Compared with sub-Tenon triamcinolone acetonide (STTA) injection, intravitreal triamcinolone acetonide injection demonstrated significantly greater improvement in visual acuity at three months (WMD -0.09, 95% CI -0.16 to -0.01; two trials) but not at six months (WMD -0.02, 95% CI -0.10 to 0.05; two trials).
Central macular thickness: Compared with placebo or no treatment, intravitreal triamcinolone acetonide injection yielded significantly greater reduction in central macular thickness at three months (WMD -130.59 μm, 95% CI -161.45 to -99.73; four trials) and at six months (WMD -53.08 μm, 95% CI -104.16 to -2.02; four trials). Compared with STTA injection, intravitreal triamcinolone acetonide injection demonstrated significantly greater reduction in central macular thickness at three months (WMD -120.77 μm, 95% CI -167.25 to -74.29; two trials) but not at six months. Significant heterogeneity was present for the comparison of intravitreal triamcinolone acetonide injection with placebo at three months (I2=74.7%). There was a discrepancy between the forest plots and texts for this comparison.
Intraocular pressure: Compared with placebo or no treatment, patients receiving intravitreal triamcinolone acetonide injection had significantly higher intraocular pressure at three months (WMD 4.33mmHg, 95% CI 2.88 to 5.77; four trials; there was a discrepancy between the forest plots and texts for this comparison) and at six months (WMD 2.40mmHg, 95% CI 1.37 to 3.44; four trials). Intravitreal triamcinolone acetonide injection demonstrated no difference in intraocular pressure at three months or six months.
The sensitivity analysis (three trials) found no significant difference in visual acuity at three months.