Color test can improve screening for chloroquine retinopathy

A color test can screen patients efficiently for retinopathy due to antimalarial drugs, a German study found.

A normal test result on computerized color testing virtually excludes any retinopathy from antimalarials, according to the study, by Aljoscha Neubauer, MD, and colleagues at Munich’s Ludwig-Maximilians University. Electro-oculograms are of little use for the same diagnosis, the study authors also found.

The researchers followed 93 patients with rheumatic diseases on long-term chloroquine and hydroxychloroquine therapy for an average of 2.6 years. Clinical exams, and electro-oculogram and a quantitative test of color vision were performed every 6 months.

Mild fundus changes were observed in 38 patients. Four patients developed bull’s eye maculopathy. Those with no fundus changes showed an elevation in tritan thresholds. The patients with bull’s eye maculopathy showed a marked disturbance of tritan color vision. A disturbance of protan vision was also an indicator of maculopathy.

Neither an absolute nor a relative electro-oculogram reduction was a valid criterion for early or late chloroquine retinopathy.

The study is published in the July issue of British Journal of Ophthalmology.