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PURPOSE Because previous studies suggested degeneration and loss of photoreceptors in aged human retina, the spatial density of cones and rods subserving the central 43 degrees of vision as a function of age was determined. METHODS Cones and rods were counted in 27 whole mounted retinas from donors aged 27 to 90 years with macroscopically normal fundi.(More)
An experimental study of lateral displacement of ganglion cells (GCs) from foveal cones in six human retinas is reported. At 406-675 microm in length, as measured in radially oriented cross-sections, Henle fibers are substantially longer than previously reported. However, a new theoretical model indicates that the discrepancies in these reports are mainly(More)
PURPOSE To develop a systematic method for identifying and grading age-related macular degeneration (ARMD) in human donor eyes, postmortem fundus appearance was compared with histopathologic assessment in eyes with a spectrum of age-related macular change. METHODS Eyes without grossly visible, late ARMD were obtained from 8 cancer patients and 26 donors(More)
PURPOSE To determine the cholesterol composition of normal human Bruch's membrane and choroid as a function of age and retinal location. METHODS Human eyes with grossly normal maculas were preserved <4 hours after donor death. Cryosections of retina and choroid from the macula and temporal equator were stained with filipin to reveal esterified (EC) or(More)
PURPOSE The authors showed previously that parafoveal rods, but not cones, decrease during the course of adulthood in donor eyes that were screened to exclude the grossly visible macular drusen and pigmentary disturbances typical of age-related macular degeneration (AMD). Because AMD begins in the parafovea, this selective loss of rods actually may be(More)
PURPOSE To examine age-related changes in the ultrastructure of Bruch's membrane with quick-freeze/deep-etch (QFDE) and conventional thin-section transmission electron microscopy (TEM). METHODS Four eyes from human donors aged 27, 41, 76, and 78 years were preserved within 4 hours of death. Full-thickness tissue blocks from the macula were prepared for(More)
1. The psychophysical spectral sensitivity of cats was assessed using a two-choice visual discrimination task by determining increment thresholds and critical flicker frequency on white and chromatic backgrounds. 2. For large increments, on 0.0, 0.3 and 3.0 cd/m2 white backgrounds, the cats were most sensitive to 497 nm indicating that these backgrounds are(More)
Visual acuity was determined for both eyes of long-term monocular-deprived cats over a wide luminance range. The influence of luminance on the rate of pattern vision recovery was also examined. Unlike strabismic humans and cats, the acuity deficit of monocularly deprived cats is not luminance dependent. This acuity is much worse at all luminance levels in(More)
Increment thresholds on a white background were determined for normal and binocularly deprived (BD) cats over a wide luminance range. Threshold vs intensity curves had a slope of unity for both groups but the increment threshold (delta I/I) for normal cats was 0.09 while increment threshold for BD cats was 0.60. Absolute threshold was reliably better in(More)
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