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Standardized full-field electroretinography. Normal values and their variation with age
1Anderson Vision Research Center, Retina Foundation of the Southwest, University of Texas Southwestern Medical Center, Dallas 75231.
Archives of Ophthalmology (Chicago, Ill. : 1960)
|November 1, 1992
Summary
Full-field electroretinograms reveal age-related declines in rod and cone vision. Normal electroretinogram (ERG) values were established, showing significant amplitude decreases and implicit time increases with aging.
Area of Science:
- Ophthalmology
- Neuroscience
- Clinical Electrophysiology
Background:
- Age-related changes in visual function are common.
- Establishing normative data for electroretinograms (ERGs) is crucial for diagnosing visual impairments.
Purpose of the Study:
- To determine age-specific normative values for full-field ERGs in healthy individuals.
- To characterize the impact of aging on rod and cone function as measured by ERG.
Main Methods:
- Obtained full-field ERGs from 269 normal subjects following International Standardization Protocol.
- Analyzed rod and cone amplitudes and b-wave implicit times across different age groups.
- Determined Naka-Rushton functions to model rod response characteristics.
Main Results:
- Rod and cone amplitudes decreased exponentially with age, halving by the late 60s/early 70s.
- B-wave implicit times increased with age for all ERG responses.
- Age-related decline in log maximum asymptotic amplitude significantly impacted rod response amplitude.
Conclusions:
- Established age-specific normal limits for ERG amplitudes and implicit times from birth to 79 years.
- Aging primarily affects the maximum asymptotic amplitude of rod responses, not the semisaturation constant.
- These findings provide essential normative data for clinical electrophysiology and research on visual aging.