Abstract
Abstract: :
Purpose: To assess the reliability of optical coherence tomography (OCT) in monitoring photodynamic therapy (PDT)– treated choroidal neovascular membranes (CNV) and its role in determining retreatment of CNV. Methods: Retrospective non– randomized interventional cross–sectional study involving patients undergoing PDT with verteporfin for subfoveal CNV.79 eyes (74 patients) who received PDT treatment for classic and predominantly classic subfoveal CNV were identified using laser log and reviewed retrospectively. Fluorescein angiography (FA) and OCT were performed at pretreatment visits and on 3 monthly follow–up examinations. OCT findings of follow–up examinations were evaluated to elucidate features of eyes needing retreatment and those that did not. Corresponding FA performed at follow–up visits were assessed for any evidence of leakage and compared with OCT findings. Results: The OCT findings of PDT–treated CNV were classified into 4 groups based on a classification system described by AH Rogers et al.(Am J Ophthalmol 2002;134(4):566–576). Stage 3a (28 eyes)CNV showed significant subretinal fluid and higher ratio of retinal fluid to subretinal fibrosis, indicating an active neovascular process. Stage 3b (24 eyes) had more prominent subretinal fibrosis with minimal intraretinal fluid, indicating a relatively inactive lesion. Stage 4 (17 eyes) showed cystoid macular oedema and Stage 5 (10 eyes) had subretinal fibrosis and atrophy indicating an inactive lesion and end–point of treatment. Of the eyes showing Stage 3a findings on OCT, 18 showed leakage on FA. In Stage 3b eyes, only 1 showed leakage while 23 did not have leakage. 12 eyes in Stage 4 showed leakage and only 1 in Stage 5 showed leakage on FA. Sensitivity of OCT in the detection of CNV requiring retreatment (showing leakage on FA) was 93.7%. Specificity of OCT was 68.1%. Of the 35 eyes (44.3%) which received retreatment on follow–up visits, 20 eyes were Stage 3a CNV and 10 eyes were Stage 4. Of those which were not retreated (44 eyes), 21 eyes were Stage 3b and 12 eyes were Stage 5. Conclusions: Optical coherence tomography proves to be a sensitive tool in monitoring and detecting patients who require retreatment of subfoveal CNV with PDT.
Keywords: choroid: neovascularization • photodynamic therapy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)