Psychophysical Evidence for Losses in Rod Sensitivity in the Aging Visual System

Abstract

Rod sensitivity was measured with a criterion-free psychophysical method at 10 deg in the horizontal meridian of the nasal field of the left eye on 26 young (mean age, 24.1 yr) and 14 older (mean age 72.6 yr) observers in good ocular health. A 1 deg, 90 msec stimulus was delivered by means of a free-viewing optical system under computer control. Stimulus wavelengths were chosen to have either significant (406 nm) or minimal (560 nm) absorption by the older lens. After correction for senile miosis and lens density, 0.39 log unit higher thresholds for the older observers remained and are interpreted as being due to neural factors.

Aging and vision

“…As far back as the 1940s it has been known that older adults have decreased light sensitivity in the dark and this deficit is larger than for photopic thresholds (Birren & Shock, 1950; Gunkel & Gouras, 1963; Jackson & Owsley, 2000; Jackson, Owsley, Cordle & Finley, 1998; McFarland, Domey, Warren & Ward, 1960; Robertson & Yudkin, 1944; Steven, 1946; Sturr, Zhang, Taub, Hannon, Jackowski, 1997; Weale, 1982b). Although increased optical density of the aged crystalline lens and pupillary miosis contribute to their scotopic threshold elevation (increasing threshold by about a 0.10–0.15 log units), more recently it has been established that these factors are not primarily responsible for this sensitivity loss, with about a half log unit elevation in threshold or more remaining after these factors are taken into account (Jackson et al, 1998; Sturr et al, 1997).…”

“…Although increased optical density of the aged crystalline lens and pupillary miosis contribute to their scotopic threshold elevation (increasing threshold by about a 0.10–0.15 log units), more recently it has been established that these factors are not primarily responsible for this sensitivity loss, with about a half log unit elevation in threshold or more remaining after these factors are taken into account (Jackson et al, 1998; Sturr et al, 1997). Only in the past decade or so has research addressed potential neural mechanisms that underlie the loss.…”

Aging-related changes in auditory and visual integration measured with MEG

“…We tested this hypothesis with realistic temporal delays for near and far sources in a perspective drawing of a soccer field. We expected the largest difference to occur with the near condition (peripheral visual condition) due to previously reported decrements in peripheral visual processing in the elderly [8, 26]. …”

Aging and mfERG topography

“…5,6 Age-related neural changes include the loss of rods, cones, and ganglion cells. [7][8][9] Psychophysical studies have demonstrated that rod-mediated sensitivity for older people is significantly lower than for younger people, 10,11 and it has been found that foveal cone sensitivity also decreases with increasing age, especially after the age of 50 years. 12,13 Earlier electrophysiological studies have shown age-related retinal changes using various ERG test protocols.…”