Abstract
Purpose:
To assess the development and resolution of axoplasmic debris, presenting as cotton-wool spots (CWS) in branch retinal vein occlusion (BRVO) as well as their predictive-value for the need of treatment over three years.
Methods:
Presence, size and fluorescent characteristics of CWS of 24 patients with BRVO≤8 weeks were retrospectively analyzed in color-fundus (CF), Spectralis SD-OCT, infrared and fluorescein-angiography (FA) every 3 months for 3yrs. Using dedicated software, images from all devices were superimposed and presentation of axoplasmic-debris was compared in a point-to-point analysis. CWS were further evaluated as predictor for the number of ranibizumab-injections and for the need of argon-laser-coagulation (ALC) over 3yrs.
Results:
29 central lesions were analyzed. At baseline, 100% of the CWS were visible in SD-OCT, only 65.5% in CF-images. 86.2% CWS presented with corresponding changes in the IR-image and 100% in the FA. 31% of the CWS were hypofluorescent, 13.8% hyperfluorescent and 55.2% were initially hypofluorescent becoming hyperfluorescent in the late-phase. Analyzing CWS-size, the mean visible area in SD-OCT was significantly greater than in CF (0.26±0.17mm2 vs. 0.13±0.1mm2, p<0.0001). The corresponding area in FA did not differ from SD-OCT (0.3±0.3mm2, p=0.17). CWS were visible for 12.4±7.5 months in SD-OCT but only 4.4±3.2 months in CF (p<0.0001). Fluorescent-changes assignable to CWS were visible for 17.5±7.1 months in FA. The visibility of CWS in CF depended on the extent of the CWS-area in SD-OCT (0.097±0.07mm2 vs. 0.25±1.75mm2, p<0.00001). CWS-area and surrounding morphology (blood, ischemia, cysts, atrophy) in SD-OCT were predictive for the length of time a CWS was visible (R2=0.497, p<0.002). The presence of CWS at baseline was neither significantly associated with the number of administered ranibizumab-injections (p=0.08) nor with applied ALC-laser (p=0.19) over 3yrs. However, hypofluorescent CWS-lesions at baseline were associated with more ALC-laser treatments (p=0.046)
Conclusions:
CWS persist significantly longer in SD-OCT than in CF thus, SD-OCT seems to be a precise tool for evaluation. Clinically relevant, hypo-fluorescent CWS at baseline seem to be predictive for hypo-perfusion and the need for laser-treatment at a later point. Therefore, those patients should regularly undergo FA to treat ischemia in a timely manner.
Keywords: 585 macula/fovea •
550 imaging/image analysis: clinical •
466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials