Comparison between Single-field Nonmydriatic Digital Fundus Image and Gold Standard for Diabetic Retinopathy Screening

ABSTRACT

Abstract Comparison between Single-field Nonmydriatic Digital Fundus Image and Gold Standard for Diabetic Retinopathy Screening Apichat       Suansilpong         MD* Petch          Rawdaree            MD** * Department of Ophthalmology, BMA Medical College and Vajira Hospital ** Department of Medicine, BMA Medical College and Vajira Hospital Objective: To determine the accuracy, sensitivity and specificity of single-field nonmydriatic digital fundus image interpreted by ophthalmologist for diabetic retinopathy screening. Study design: Diagnostic test. Subjects: Two hundred and forty-eight diabetic patients who attended the Diabetic Center, BMA Medical College and Vajira Hospital during May 2007 and March 2008 were enrolled. Methods: The fundi of all patients were captured using nonmydriatic digital fundus camera, the single-field fundus image included optic nerve and macular area. Fundus images were interpreted by ophthalmologist. After digital retinal image capture, patients were examined for detecting diabetic retinopathy by ophthalmologist as a gold standard. All data were recorded for statistical analysis. Main outcome measures: Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. Results: The prevalence of eyes with diabetic retinopathy was 22.8%. The prevalence of patients with diabetic retinopathy was 24.2%. Of the 60 patients, who had diabetic retinopathy, there were 7 patients whom diabetic retinopathy was detected in one eye. In 40 eyes of 248 diabetic patients, the images were of low quality, which could not be used for the interpretation. The accuracy for screening diabetic retinopathy was 89.3% (95% CI 86.0-91.9) the sensitivity and the specificity for screening diabetic retinopathy were 72.6% (95% CI 68.6-76.7) and 94.3% (95% CI 92.1-96.4) respectively. Positive predictive value and negative predictive value were 79.4% (95% CI 75.7-83.1) and 91.9% (95% CI 89.4-94.4) respectively. Conclusion: Single-field nonmydriatic digital fundus image can be used for screening of diabetic retinopathy but can not replace standard eye examination. Vajira Med J 2008 ; 52 83 - 91