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J. N. Ver Hoeve, C. B. Y. Kim, T. M. Nork, B. J. Christian, P. E. Miller; Standardized Full-Field Electroretinography in Cynomolgus Monkeys. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5816. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To provide normal values for rod and cone ERGs in anesthetized young adult male and female monkeys tested using the standard protocol suggested by the International Society for the Clinical Electrophysiology of Vision.
Full-field electroretinograms were recorded in 95 male and 95 female cynomolgus monkeys (380 eyes) as part of pre-dosing baseline examinations for drug safety studies. All of the animals were naïve to previous experimental treatments and had baseline fluorescein angiograms and/or ophthalmic examinations. Animals were dark-adapted for a minimum of 2 h, anesthetized with ketamine and xylazine and body temperature and sPO2 were monitored. Following pupillary dilation, the ERG was recorded from monopolar JetTM contact lens electrodes with reference electrode placed near the outer canthus. The scotopic ERG was recorded to a dim rod-isolating flash and the standard flash (2.9 cd-s m-2). A non-standard scotopic red flash was also recorded. Animals were then light-adapted for 10 min and photopic single and 30 Hz flicker responses to the standard flash were obtained. The amplitude and implicit times of the a- and b-waves and oscillatory potentials were determined using automated software routines.
Similar to human normative data scotopic and photopic ERG amplitudes followed a log-normal distribution. Parametric tests on log-transformed amplitudes revealed no significant gender differences in the mean ERG amplitudes under scotopic or photopic conditions. Scotopic Dim and Standard Flash grand means and 99% confidence intervals were 190 (± 20), 305 (± 17) mcV, respectively. Photopic Standard and 30 Hz mean amplitudes were 101 (± 7) and 69 (± 5) mcV, respectively. Inter-ocular correlations were significant for all conditions, with r2 ranging from .44 to .80.
This data set provides normative values for ERG parameters in cynomolgus monkeys recorded under a standard clinical protocol. The non-human primates in this study were of similar age, dietary history, and matched on inter-individual variables that are often uncontrolled in human normative studies. This data set therefore provides a lower limit on expected variability in clinical ERG studies and normal values for cynomolgus monkeys tested under the ISCEV standard protocol.
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