The Detection of Retinal Never Fiber Layer Defect by Modification of Non-mydriatic Digital Fundus Photograph

ABSTRACT

PURPOSE: To evaluate the efficiency of digital retinal nerve fiber layer (RNFL) photographs converted from a non-mydriatic digital fundus camera for detecting RNFL defects. METHODS: Ninety-five eyes were evaluated with both a non-mydriatic digital fundus photograph and a digital RNFL photograph by two glaucoma specialists independently. The red-free, monochrome modified digital fundus photograph was acquired from non-mydriatic digital fundus photographs using Photoshop 7.0. Whether a localized wedge-shaped or diffuse RNFL defect existed or not was evaluated on a non-mydriatic digital fundus photograph and a modified digital fundus photograph, and inter- and intraobserver agreement were also evaluated. Regarding the use of digital RNFL photographs as a standard method, we calculated the sensitivity, specificity, and positive and negative predictive values of the two types of photographs. RESULTS Interobserver agreement (Cohen's kappa values) about localized RNFL defects observable on digital RNFL photographs, non-mydriatic digital fundus photographs, and modified digital fundus photographs were 0.749, 0.634, and 0.793, respectively, but all were 0.417 or less with regard to diffuse RNFL defects. Regarding localized RNFL defects, the sensitivity, specificity, and positive and negative predictive values of modified digital fundus photographs were 85.7%, 95.5%, 85.7% and 94.1%, respectively, showing superiority to those of non-mydriatic digital fundus photographs. But, in cases of diffuse RNFL defect, the sensitivity and specificity of modified digital fundus photographs were 60.0% and 97.8%, respectively, indicating no superiority to non-mydriatic digital fundus photographs. CONCLUSIONS: The localized RNFL defect can be detected more efficiently with modified digital fundus photographs than non-mydriatic digital fundus photographs, but the diffuse RNFL defect cannot.