Detection of Chloroquine Retinal Toxicity on Perimetric Findings in 52 Rheumatoid Arthritis Patients with Normal Findoscopic Findings Referred to Rasoul-e-Akram Hospital

Chloroquine and its congeners are antimalarial agents which have anti rheumatic properties. One of the most important side effects of these drugs is retinal toxicity. Different methods have been used for early detection of this complication but there is no firm consensus about the best one. The purpose of this study was to assess the value of central 2-10 perimetry in early detection of retinal toxicity. This prospective cross-sectional study was performed on 63 rheumatoid arthritis patients, who had been receiving chloroquine for at least 6 months and still were continuing this medication. All of the patients were examined by an ophthalmologist through direct and indirect ophthalmoscopy as well as central 2-10 perimetry. 21 of the cases were subjected to another perimetry, 3 to 12 months after the first perimetry. All the perimetric studies were interpreted by the same ophthalmologist. 2 out of 63 patients had macular pigmentary changes, 6 patients had cataract, 6 had corneal pigmentation and 3 ones were affected by both cataract and corneal pigmentation. Of 42 patients who were assessed by perimetry, 30 patients(71.4%) had normal results and 12 patients(28.6%) showed abnormal results. Out of 21 patients who were subjected to repeat perimetry, 11(52.4%) and 10(47.6%) patients had normal and abnormal results, respectively. In the latter group, in 8 patients(80%), despite continuing chloroquine, the second perimetric examination was normal unexpectedly. In 2 patients the second perimetric exam was worse and both of them had sustained cataract and corneal pigmentation. In 3 out of 11 patients(27.3%), who had normal result, the second perimetric examination showed some progression therefore, chloroquine was stopped in those patients. In this study the prevalence of chloroquine retinal toxicity was 5.9%. No correlation was found between accumulative and daily chloroquine dosages and perimetric results(P>0.7, P>0.8). Cataract as an underlying occular disease affected significantly the results of perimetric examinations(P<0.002). Corneal and macular pigmentation did not affect perimetric results(P>0.13, P>0.9). Central 2-10 perimetry is a useful method for early detection of chloroquine retinal toxicity, but concordant ophthalmologic examinations and regular periodic perimetric examinations is mandatory to confirm chloroquine retinal toxicity.