Abstract
Purpose: :
To investigate the effects of bevacizumab (Avastin, Genentech, Inc.) on retinal morphology in patients with neovascular age-related macular degeneration (AMD) using optical coherence tomography (OCT) quantitative subanalysis.
Methods: :
Data from 75 patients receiving intravitreal bevacizumab for neovascular AMD were collected. StratusOCT images were analyzed using custom software entitled "OCTOR" which allows precise positioning of pre-specified boundaries on OCT B-scans. Changes in thickness/volume of the neurosensory retina, subretinal fluid, subretinal tissue, and pigment epithelium detachments were calculated at months 1, 3, 6 and 9 post-treatment.
Results: :
By month 1, the neurosensory retina showed an average 59 µm decrease from baseline in foveal center point thickness. This effect was maintained for the remainder of the study, with a decrease from baseline of 61 µm by month 3, 60 µm by month 6, and 47 µm by month 9. Total retinal volume reached its nadir at month 3, with an average reduction of 0.79 mm3. By month 9, this initial reduction had attenuated to 0.61 mm3. Total subretinal fluid volume reached its lowest level by month 1, with an average reduction of 0.32 mm3. This reduction attenuated subsequently, to 0.18 mm3 by month 9. There was an average 0.2 mm3 decrease in total volume of pigment epithelium detachment by month 1, and this reduction was maintained at month 9. Total subretinal tissue volume was reduced by an average of 0.15 mm3 by month 1, with further reduction to 0.28 mm3 by month 9.
Conclusions: :
Initiation of treatment with intravitreal bevacizumab led to significant reductions in intraretinal and subretinal fluid accumulation, which were largely maintained by the conclusion of the study and were comparable with similar studies on intravitreal ranibizumab (Lucentis, Genentech Inc.). The effect of intravitreal bevacizumab on the volume of pigment epithelium detachment was less pronounced. Manual segmentation of OCT images may allow a more precise understanding of anatomic outcomes in clinical trials of anti-angiogenic therapies.
Clinical Trial: :
NEI Grant R01 EY014375
Keywords: age-related macular degeneration • imaging/image analysis: clinical • clinical research methodology