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STANDARDS OF FUNCTIONAL MEASUREMENTS IN OCULAR TOXICOLOGY.
Citation:
Boyes, W K. STANDARDS OF FUNCTIONAL MEASUREMENTS IN OCULAR TOXICOLOGY. Presented at American College of Toxicology, Washington, DC, November 6, 2001.
Description:
The visual system, like other sensory systems, may be a frequent target of exposure to toxic chemicals. A thorough evaluation of visual toxicity should include both structural and functional measures. Sensory evoked potentials are one set of neurophysiological procedures that are well adapted to neurotoxicity testing. Sensory evoked potentials are elicited by sensory stimuli, recorded from multicellular electrodes, and reflect the functional status of the sensory system understudy. The USEPA has developed health effects testing guidelines entitled Neurophysiology: Sensory Evoked Potentials (OPPTS 870.6855), which are available at the internet address listed below. The guidelines cover testing of visual, auditory and somatosensory systems. Information concerning the principle of the test methods, experimental design and conduct, methods and procedures, data evaluation and quality control is provided. Visual system testing includes both flash and pattern stimuli, which may be differentially sensitive to toxicant-induced dysfunction. Toxicological testing protocols for electroretinography (ERG) have also have also been developed, although official EPA guidelines for ERGs have not been published. Technology is being developed to enhance the capacity for multi-subject and multi-sensory system evoked potential testing. In addition to testing applications, sensory evoked potentials can be adapted for in-depth study of sensory toxicity, such as measuring visual contrast sensitivity thresholds, or for other purposes such as development of exposure-dose-response models for more mechanistic approaches to risk assessment. The address for the guidelines is:
http:/www.epa.gov/docs/OPPTS_Harmonized/870_Health_Effects_Test_Guidelines/Series/
(click on 870.6855). This abstract does not reflect EPA policy.