Abstract
Purpose: :
Anti-VEGF-therapy with Ranibizumab has been shown to be an effective treatment for specific types of exudative AMD, but a clinical distinction between patients likely to have improved visual acuity (VA) and less favourable visual outcome is not possible. RPE-autofluorescence (AF) has been demonstrated as indicator for RPE function and microperimetry as indicator for photoreceptor function. The aim of present prospective study was to test these two techniques as prognostic parameters in anti-VEGF therapy.
Methods: :
120 patients (72 f, 48 m; mean age 74y.) were treated three times with Ranibizumab (4 weeks intervals). AF images were obtained with HRA 2 (Heidelberg Engineering) and the central RPE-AF within 250 µm around the foveola analyzed (normal AF in 68 eyes vs changed AF in 52 eyes). In addition miroperimetry (foveal sensitivity below vs above 4dB), VA and retinal thickness (OCT) was analyzed.>
Results: :
Before treatment the distribution of VA was similar between both groups (normal AF: logMAR 1.0 in 7.1%; changed AF: logMAR 1.0 in 21%; p=.3), but after treatment (3 mo) a significant difference existed (normal AF: logMAR 1.0 in 4%; changed AF: logMAR 1.0 in 20%; p=.004). Especially the changes in VA during therapy was different between both AF groups (normal AF: increased VA 84%, stable VA 16%, decreased VA 0%; changed AF: increased VA 25.8%, stable VA 37.1%, decreased VA 37.1%; p<.0001). In contrast the reduction in retinal thickness (OCT) was similar in both groups (normal AF: mean reduction 98ѵm; changed AF: mean reduction 82ѵm; p=0.6). When divided according to microperimetric foveal sensitivity (below vs above 4dB) the VA was also similar before therapy (p=0.1), but after 3 mo despite similar reduction in retinal thickness (80ѵm vs 120ѵm; p=.2) a significant difference in VA between both groups was found (p=.002). Combining both parameters the best chances for increasing VA existed in patients with normal AF and retinal sensitivity above 4dB (diff. -0.25 logMAR) and worst in patients with changed AF and ret. sensitivity below 4dB (diff. 0.04 logMAR).
Conclusions: :
The results of this study demonstrate that despite similar reduction in retinal thickness, the analysis of foveal RPE-AF and foveal retinal sensitivity are significant prognostic factor to determine the functional outcome after anti-VEGF therapy in AMD. Only with normal foveal AF increase in VA can be expected, which is especially marked, if the foveal sensitivity was >4dB.
Keywords: age-related macular degeneration • choroid: neovascularization • vascular endothelial growth factor