Diagnostic accuracy of direct ophthalmoscopy in the rapid assessment of avoidable blindness protocol: A cross-sectional study

Abstract

Background: Rapid Assessment of Avoidable Blindness (RAAB) relies mainly on direct ophthalmoscopy (DO) for the diagnosis of posterior segment eye diseases (PSEDs). There is, however, a growing concern that DO may not be sufficiently sensitive to detect PSED owing to inherent diagnostic limitations. Aim of the Study: The aim of the study was to determine the sensitivity and specificity of DO for the detection of PSEDs in RAAB, using indirect ophthalmoscopy (IO) as a reference standard. Materials and Methods: Participants were patients 50 years and older, presenting to the eye clinic of a tertiary hospital in Jos, between April and September 2016 who gave consent. Their visual acuity was assessed as is done in RAAB6. Those found to be unilaterally or bilaterally visually impaired underwent anterior and posterior segment eye examinations to identify the cause. Dilated fundoscopy was first performed by a senior ophthalmology resident with DO (index test), followed by IO (reference standard test) by a consultant ophthalmologist. Results: A total of 250 patients were recruited into the study, of which 188 took the index and reference standard tests. PSEDs were detected in 65 (34.6%) persons and glaucoma accounted for 87.7% of these. The sensitivity of DO for the detection of glaucoma was 95.3%, while the specificity was 91.0%. Sensitivity and specificity for the detection of diabetic retinopathy and central retinal vein occlusion were both 100%. Specificity for the detection of other PSEDs was good even though sensitivity was below acceptable limits. Conclusion: The performance of DO against IO in this study, suggests that it is a satisfactory modality for the detection of the most common PSEDs in RAAB.

Keywords

• rapid assessment of avoidable blindness
• sensitivity
• specificity