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Contrast sensitivities were measured in human observers of different ages in response to sinusoidal grating patterns generated by laser interferometer and cathode ray tube (c.r.t.). The former method bypasses the effects of the optical media to assess directly the contrast sensitivity of the retina/visual system, while the over-all assessment including(More)
The ability to make egocentric distance estimates of a single point source of light, seen in darkness and without the cues of changing size and luminance, was investigated in sixteen observers. The attenuation required to maintain constant luminance, when the target was viewed from different distances, was shown to follow the inverse square law providing(More)
1. The aim of this study was to assess the contribution of retinal ganglion cells to the decline in contrast sensitivity during human ageing. 2. After determination of the appropriate refraction for each subject, younger subjects were arranged to be exposed to a display luminance which was suprathreshold by the same amount as in older subjects wearing a 4.0(More)
The N1, P1, N2 and P2 components of the pattern visual evoked response (PVER) have been recorded to the onset of presentation of a sinusoidal grating pattern of 3 and 8 cycles/deg in groups of young (15-34 years) and old (53-94 years) subjects. The negative components were taken to arise from striate cortex and the positive components from extrastriate(More)
We have measured monocular and binocular contrast sensitivities in response to medium to high spatial frequencies of vertical sinusoidal grating patterns in normal subjects, anisometropic amblyopes, strabismic amblyopes and non-amblyopic esotropes. On binocular viewing, contrast sensitivities were slightly but significantly increased in normal subjects,(More)
BACKGROUND There is a considerable body of literature which indicates that contrast thresholds for the detection of sinusoidal grating patterns are abnormally high in glaucoma, though just how these elevations are related to the location of visual field loss remains unknown. Our aim, therefore, has been to determine the relationship between contrast(More)
Visual performance was measured in sixty-six subjects aged from 5 to 94 years. The curve of contrast sensitivity against spatial frequency was obtained for each subject. This curve had a peak contrast sensitivity in the 2-6 c/deg (cycles/degree) range with the fall-offs to either side of the peak described, on a double logarithmic plot, by straight lines.(More)
The postnatal development of the area centralis of the kitten retina was followed with the electron microscope. After birth, small but well developed photoreceptor outer segments were observed. Cone pedicles formed triads and bipolar cells formed dyads; so, potentially, cone pathways to the ganglion cell were present at this time. By the start of the second(More)
BACKGROUND Predictions from conduction velocity data for primate retinal ganglion cell axons indicate that the conduction time to the lateral geniculate nucleus for stimulation of peripheral retina should be no longer than for stimulation of central retina. On this basis, the latency of saccadic eye movements should not increase for more peripherally(More)
AIMS Previously, we demonstrated that gastrin peptides as long as 34 amino acids were absorbed from the ileum of rat after conjugation to the C24 position of cholic acid and that these peptides retained full biological activity. As absorption was specific to the ileum, it was inferred that the conjugated hormone was taken up by the bile salt transporters.(More)