Accuracy of Amsler grid in screening for chloroquine retinopathy.

OBJECTIVE: Determine the accuracy, sensitivity, and specificity of an Amsler grid testingfor chloroquine retinopathy screening. MATERIAL AND METHOD: One hundred and forty patients who received chloroquine phosphate or hydroxychloroquine sulfate and attended the rheumatology clinic of BMA Medical College and Vajira Hospital between March 2008 and May 2009 were included. The patients underwent Amsler grid testing, which would be interpreted by a rheumatologist, for any evidence of chloroquine retinopathy. The resultsfrom Amsler grid testing were then compared to the results from a Humphrey 10-2 fields testing, which was subsequently performed by an experienced ophthalmologist and was used as a gold standard. RESULTS: Out of 140 patients, chloroquine retinopathy was evidenced in 11 patients (7.9%). Kappa value of the Amsler grid testing interpreted by rheumatologist and the Humphrey 10-2 fields testing interpreted by ophthalmologist was 0.89. The accuracy for screening chloroquine retinopathy by the Amsler grid testing was 98.6% (95% confidence interval [CI], 98.1-100.0%) with the sensitivity of81.8% (95% CI, 75.4-88.2%). The specificity and positive predictive value were 100.0% while the negative predictive value was 98.4% (95% CI, 96.4-100.0%). CONCLUSION: Amsler grid testing is an accurate screening test for chloroquine retinopathy with very high specificity. The test could be achieved by a rheumatologist who could practically serve the patients in one visit at the rheumatology clinic.

Accuracy of single-field nonmydriatic digital fundus image in screening for diabetic retinopathy.

OBJECTIVE: To determine the accuracy, the sensitivity and the specificity of a single-field nonmydriatic digital fundus image interpreted by an endocrinologist for diabetic retinopathy (DR) screening. MATERIAL AND METHOD: Two hundred and forty-eight diabetic patients who attended the Diabetic Center BMA Medical College and Vajira Hospital between May 2007 and March 2008 were included in the present study. The fundus images of all patients, which would include optic nerve and macular area, were captured by a digital camera without any mydriatic agent. After image taking, the patients were subsequently examined for any evidence of diabetic retinopathy by an experienced ophthalmologist. The fundus images were later interpreted by a trained endocrinologist and would be compared with the findings from the ophthalmologist, which were used as a gold standard RESULTS: The prevalence of DR was 24.2% of the population or 22.8% of the 495 eyes studied. Ninety-three fundus images were considered low quality for interpretation and were excluded from the analysis. From the remaining 402 eyes (155 patients), the Kappa value of the endocrinologist's interpretation and the ophthalmologist's findings was 0.48. The accuracy for screening DR by the image capture was 80.6% (95% confidence interval [CI], 76.4-84.3) while the sensitivity and specificity were 65.6% (95% CI, 60.9-70.2) and 84.9% (95% CI, 81.4-88.4), respectively. Positive predictive value and negative predictive value were 55.7% (95% CI, 50.8-60.5) and 89.5% (95% CI, 86.5-92.5), respectively CONCLUSION: Single-field nonmydriatic digital fundus image is a convenient screening tool for a diagnosis of diabetic retinopathy. The test could be achieved by a trained endocrinologist who could practically serve the patients in one visit at diabetic clinics. A referral to an ophthalmologist is still recommended in any cases with abnormal findings, or those with questionable findings, and those with poor quality photographs when diabetic retinopathy could not be definitely excluded.