Accuracy of Amsler grid in screening for chloroquine retinopathy.
OBJECTIVE
Determine the accuracy, sensitivity, and specificity of an Amsler grid testingfor chloroquine retinopathy screening.


METHODS
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%).


CONCLUSIONS
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.
Suansilpong
Apichat
A
Department of Ophthalmology, BMA Medical College and Vajira Hospital, Bangkok, Thailand. apichat_suan@yahoo.com
Uaratanawong
Somchai
S
D000328:Adult; D018501:Antirheumatic Agents / Q000009:adverse effects*; D002738:Chloroquine / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012164:Retinal Diseases / Q000139:chemically induced* / Q000175:diagnosis*; D015351:Vision Screening / Q000379:methods*; D014794:Visual Fields
D018501:Antirheumatic Agents; D002738:Chloroquine