Detection of Early Hydroxychloroquine Retinal Toxicity Enhanced by Ring Ratio Analyi of Multifocal Electroretinography Original Reearch Article

Purpoe To ae decreaed retinal function aociated with high cumulative doe of hydroxychloroquine uing multifocal electroretinography (mfERG). Deign Retropective cro-ectional tudy. Method ixty-two patient referred for evaluation of hydroxychloroquine retinal toxicity. Control were 67 normal eye of 67 patient referred for a variety of condition in the other eye. Viual ymptom, duration of treatment, daily hydroxychloroquine doe (milligram and milligram per kilogram), cumulative doe, condition for which the drug wa taken, viual acuity, retinal examination, viual field, and mfERG amplitude. The average mfERG amplitude wa calculated for five concentric ring. The age-corrected amplitude of the central hexagon (R1) and the ratio of R1 to each of the other ring (e.g., R1/R2, R1/R3) were compared with limit derived from control eye. Reult The incidence of characteritic mfERG abnormalitie in patient referred for evaluation with cumulative hydroxychloroquine doe of more than 1250 g wa nearly 50%. It wa 2.8 time that found in patient with cumulative doe le than 1250 g. ignificant abnormalitie were een with cumulative doe a low a 400 g. The mfERG abnormality mot commonly detected wa an increaed R1/R2 ratio. Cumulative doe wa more predictive of mfERG abnormalitie than daily doe (either in milligram or milligram per kilogram) or duration of treatment. Concluion Functional teting of the retina with mfERG how locally decreaed retinal function in a large fraction of patient referred for evaluation who have taken high cumulative doe of hydroxychloroquine. A prudent mfERG teting trategy i propoed.