Abstract
Abstract: :
Purpose: Optimal screening for ocular toxicity caused by chloroquine and hydroxychloroquine is still controversial. With the multifocal pattern electroretinogram (mfPERG) a new electrophysiologic technique has recently become available to detect early changes of ganglion cells. In this study this new technique is applied to a consecutive series of 10 patients receiving long-term chloroquine medication. Methods: In 10 consecutive patients receiving chloroquine medication clinical examination, Amsler visual field testing and computerized color vision testing were performed. If toxicity was suspected, automated perimetry was used. In addition, in all patients conventional pattern ERG (PERG) and mfPERG testing were performed. Results: On clinical examination 2 patients were found to have advanced maculopathy, while 8 did not show chloroquine-associated maculopathy. On Amsler testing only one patient recognized existing field defects, while automated perimetry showed typical paracentral scotomas on both affected patients. Color vision testing showed significantly abnormal test results in the patients with chloroquine maculopathy. Of the normal patients 4 from 8 showed a mild color vision disturbance, which correlated to aged related macula changes. Amplitudes of PERG and the central responses of the mfPERG were markedly reduced in chloroquine maculopathy, while the latencies were unchanged. Peripheral rings of mfPERG were not affected by chloroquine toxicity. Both, PERG and mfPERG were not significantly changed by age related macular changes. Conclusions: The reduction of PERG and central mfPERG responses in chloroquine retinopathy supports the theory that macular ganglion cells are affected first in toxicity. Screening for retinopathy can be improved by using those electrophysiological tests. Applying a sensitive colour test to clinical routine examination allows easy detection of macular changes.
Keywords: electrophysiology: clinical • retina