The multifocal pattern electroretinogram in chloroquine retinopathy

Purpose: Optimal screening for ocular toxicity caused by
chloroquine and hydroxychloroquine is still controversial. With the
multifocal pattern electroretinogram (mfPERG), a new
electrophysiological technique has recently become available to
detect early changes of ganglion cells. In this study this new
technique is applied to a series of 10 patients seen consecutively
receiving long-term chloroquine medication. Methods: In 10 patients
receiving chloroquine medication, clinical examination, Amsler
visual field testing and computerized color vision testing were
performed. If toxicity was suspected, automated perimetry was
carried out. In addition, in all patients conventional pattern
electroretinogram (PERG) and mfPERG testing were performed.
Results: On clinical examination 8 patients showed no
chloroquine-associated maculopathy, while 2 patients did. Of these
2, only 1 reported abnormalities when viewing the Amsler chart,
while automated perimetry showed typical, ring-like paracentral
scotomas in both affected patients and color vision was
significantly abnormal. In the normal patients, 4 of 8 had a mild
color vision disturbance, which correlated to age-related macular
changes. The amplitudes of the PERG and the central (approximately
10degrees) responses of the mfPERG were markedly reduced in
chloroquine maculopathy, while the latencies were unchanged. The
peripheral rings of mfPERG (ranging to 48degrees) were not affected
by chloroquine toxicity. Both PERG and mfPERG were less affected by
age-related macular changes. Conclusions: The reduction of PERG and
central mfPERG responses in chloroquine maculopathy may help with
the early detection of toxicity. Copyright (C) 2004 S. Karger AG,
Basel.