Age-related changes in the flash electroretinogram and oscillatory potentials in individuals age 75 and older

OBJECTIVES: To evaluate whether the inner plexiform layer of the retina is altered during senescence by examining the oscillatory potentials (OPs) of the flash electroretinogram (fERG) in individuals age 75 and older. DESIGN: Cross-sectional, observational study. SETTING: A university-based center. PARTICIPANTS: Fifty-six healthy volunteers (age 20-88 years). MEASUREMENTS: fERGs and OPs were first evaluated in scotopic conditions, following pupillary dilation and dark adaptation, in young (20-32 years; n = 30) and older (75-88 years; n = 26) individuals. Electrical signals were recorded with a Dawson-Trick-Litzkow type (DTL) fiber electrode in response to blue and white flashes. Red flashes were subsequently delivered to the test eye for photopic fERG and OP recordings following a period of light adaptation. RESULTS: The amplitude of the a- and b-waves in response to blue and white flashes was, significantly decreased in older people and their implicit time was increased. The latency of the a- and b-waves under photopic conditions was also prolonged with senescence, but only the amplitude of the b-wave was reduced. The amplitude of most OPs recorded under both scotopic and photopic conditions decreased with age, whereas their implicit times were prolonged. CONCLUSIONS: Our results confirm previous findings regarding the age dependency of the fERG a- and b-waves. Furthermore, we provide novel information concerning the detrimental effects of age on the OPs, indicating that the neuronal elements within the inner plexiform, layer of the retina are compromised with senescence.