Abstract
Purpose: :
It has been shown that the macular thickness is increased immediately following photodynamic therapy (PDT) due to an acute inflammatory response. The purpose of this study was to determine whether an intravitreal injection of bevacizumab (1.25 mg/0.05ml) or a posterior juxtascleral injection of triamcinolone acetonide (TA, 20 mg/0.5ml), given before PDT in eyes with age-related macular degeneration (AMD), will reduce the incidence of retinal/subretinal fluid accumulation soon after PDT.
Methods: :
Ninety-two eyes of 89 patients with neovascular AMD that were treated initially by PDT with either intravitreal bevacizumab (IVB-PDT group; n=41) or posterior juxtascleral TA (TA-PDT group; n=51) were studied. Fifty-four eyes of 54 consecutive patients treated with PDT alone (PDT alone group) were studied as controls. The bevacizumab or TA was given 1 week before the PDT. Six Stratus optical coherence tomographic (OCT) images centered on the fovea were recorded before treatment, 1 week after the injection of bevacizumab or TA (just before PDT), and 1 week after PDT using the Fast Macular Thickness Map protocol. The average macular thickness within a 3 mm diameter circle centered on the fovea was calculated using a manually-assisted computer algorithm which allowed us to draw spline lines on the principal points of the OCT images.
Results: :
The change in the mean macular thickness before and after treatment remained almost unchanged in the PDT alone group (before treatment; 326.3 ± 64.1 µm, and 1 week after PDT; 329.3 ± 78.1 µm, P = 0.60, Wilcoxon signed-rank test). In the TA-PDT group, the mean macular thickness decreased from 326.9 ± 58.8 µm before treatment to 312.1 ± 53.3 µm at 1 week after the injection of TA (just before PDT, P = 0.10) and increased to 334.9 ± 84.1 µm at 1 week after PDT(P = 0.88). In the IVB-PDT group, the mean macular thickness significantly decreased from 327.5 ± 57.1 µm before treatment to 303.5 ± 58.4 µm at 1 week after IVB ( just before PDT, P < 0.0001) and was still significantly reduced at 310.8 ± 67.6 µm at 1 week after PDT (P = 0.0007).The proportion of eyes with a >10% increase in thickness at 1 week after PDT compared with just before PDT was lower in the IVB-PDT group (7/41 (17%) eyes) than that in the PDT alone group (16/54 (30%) eyes) and in the TA-PDT group (15/51 (29%) eyes), but the differences were not significant (P = 0.28, Chi-square test).
Conclusions: :
Combined IVB with PDT significantly reduced the macular thickness at 1 week after PDT. The incidence of the transient increase in the macular thickness just before and after PDT was not significant among these treatment protocols.
Keywords: age-related macular degeneration • photodynamic therapy • imaging/image analysis: clinical