2017 Volume 36 Pages 1-6
Electroretinography (ERG) is a useful method for a quantitative evaluation of retinal function. However, the full-field ERG detects total electrical potential from the entire retina and it is hard to detect localized retinal abnormalities. In this study, we investigated the usefulness of focal ERG examination in cynomolgus monkeys. We recorded the waveform in focal ERG in the macula and temporal retina of both eyes in 15 males and 15 females for basic data collection. The local retinal degeneration model was produced by a single subretinal injection of cobalt chloride (CoCl2, 0.40 mg/mL, 30 µL/eye), and the reaction was measured by both the full-field ERG and focal ERG. In addition, the eyes were investigated by optical coherence tomography (OCT), fluorescein angiography (FA), and histopathology. No apparent difference was noted in focal ERG between males and females, or between the right and left eyes. Both a-wave and b-wave of the macular part showed a higher potential than that of the temporal part of the retina. In the local retinal degeneration model, no abnormality was noted in the full-field ERG, while in the focal ERG examination, response losses were noted in both a-wave and b-wave for at least 28 days after a single CoCl2 injection. The focal ERG changes were related to the OCT, FA, and histopathological findings. These results suggest that the focal ERG examination is useful for evaluation of local ocular toxicity in cynomolgus monkeys.
