Accuracy of Funduscopy to Identify True Edema versus Pseudoedema of the Optic Disc.

Purpose: Differential diagnosis between acute optic disc edema (ODE) and optic disc pseudo-edema (PODE) may be a clinical challenge even for well-trained ophthalmologists. Funduscopy remains the first-line investigation. The aim of this study was to assess the accuracy, sensitivity, and specificity of funduscopy in differentiating ODE from PODE. Methods: Observational, cross-sectional, two-center study of subjects referred for presumed acute ODE. During funduscopy each observer completed a form concerning the presence/absence of the ten conventional signs of ODE. 74 patients with ODE and 48 subjects with PODE were included in the analysis. Accuracy, sensitivity, and specificity from all possible combinations of signs were calculated by Support Vector Machine (SVM) analysis. Results: As a single sign, the swelling of the peripapillary retinal nerve fiber layer had the highest accuracy (0.92; 95% CI: 0.82–0.97). Little variation was observed when more than fours signs were present; the best four-sign combination was: SWELLING, HEMORRHAGES, papilla ELEVATION, and CONGESTION of peripapillary vessels (accuracy = 0.93, 95% CI: 0.83–0.98; sensitivity = 0.95; and specificity = 0.89). The presence of retinal and/or choroidal folds appeared to be a pathognomonic sign of true ODE (100% of sensitivity), but with a low rate of presentation (23%). Conclusions: The presence of at least four ophthalmoscopic signs (with the sign “swelling” included) gives the highest accuracy. Furthermore, peripapillary retinal folds seem to be related exclusively to ODE, since they were never observed in our PODE group. These data may be useful for clinicians when evaluating patients referred for presumed optic disc edema in the acute phase.