Purpose: To assess the sensitivity and specificity of optical coherence tomography (OCT) for monitoring patients with choroidal neovascularization (CNV) after photodynamic therapy (PDT) in comparison to fluorescein angiography (FA).
Methods: Prospective study of 14 patients with CNV secondary to age-related macular degeneration receiving PDT. Best-corrected visual acuity (BCVA), fluorescein angiography, and OCT (Zeiss Stratus OCT3) were performed before and at 2, 6, 12, and 24 weeks after treatment. FA images were assessed for leakage and presence of subretinal or intraretinal fluid was assessed on OCT images. Retinal thickness was measured automatically. OCT sensitivity and specificity levels for detecting leaking CNV were calculated. Retinal thickness was correlated with visual acuity.
Results: Mean follow-up time was 14.1 weeks. Sixty-one OCT/FA examinations were analyzed. Thirty-one examinations presented leakage (51%). OCT showed intraretinal fluid in 46 (75%) and subretinal fluid in 30 cases (49%). In 49 cases (80%), either intraretinal or subretinal fluid was present. Sensitivity for detecting intraretinal fluid in OCT was 90% (specificity 40%) and 71% (specificity 73%) for subretinal fluid. Combined sensitivity for intraretinal or subretinal fluid was 97% (specificity 37%). Increased central foveal thickness correlated with decreased BCVA. Correlations were significant (p<0.05).
Conclusions: OCT showed good sensitivity in detecting active CNV. Specificity was only moderate. Central foveal thickness correlated negatively with visual acuity. Owing to different aspects of active CNV shown by FA and OCT, OCT should be combined with other examinations, and may not substitute FA for indication/reindication of PDT but can be a valuable addition in difficult cases.