The unreliability of subjective probe estimates of cyclofusional vergence performance.
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Evaluation Studies as Topic↗
Biomedical subjects
D R Hampton
Publications and source records attributed to D R Hampton.
The unreliability of nonius line estimates of vertical fusional vergence performance.
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Depth Perception↗
The extent of Panum's area and the human cortical magnification factor.
The horizontal extent of Panum's fusional area was measured by means of a single-vertical-line stimulus placed at thirty-two locations throughout the peripheral visual field. These results were transformed by using known values of the human cortical magnification factor (CMF), and the hypothesis that variations in the magnitude of Panum's area may be accounted for by variations in the CMF was tested. It was found that the increase in Panum's area with increasing stimulus eccentricity correlates well with the CMF, but that variations in the extent of Panum's area as a function of angular position around the line of sight do not correspond well with the CMF.
Adult↗
Fusional vergence response to local peripheral stimulation.
Horizontal, convergent disparities were introduced between dichoptic stimuli confined to small regions of the peripheral retina. Stimuli were presented at 32 locations: radial positions varied in 5-deg increments up to 20 deg, while angular position varied in 45-deg steps. The stimulus size and disparity were scaled in accordance with the cortical magnification factor. Eye movements were objectively measured, and the relative contributions of the motor and nonmotor components to the fusional response were evaluated as a function of stimulus eccentricity and angular position. Vergence responses elicited by peripheral disparities had longer latencies and durations and were more asymmetric than the movements elicited by foveal disparities. The composition of the fusional response changed with the position of the stimulus. The largest percentage of motor compensation was observed for stimuli located either near the line of sight or directly above it. The variations in the size of the motor response with increasing eccentricity could not be explained by the cortical magnification factor.
Depth Perception↗
Human response to cyclofusional stimuli containing depth cues.
The cyclofusional response to stimuli containing depth cues was studied. Eye positions were monitored by an objective, binocular, eye movement measuring technique while a psychophysical method was used to measure the stereoscopic responses. We found that the overall response contains both stereoscopic and cyclofusional components and that the cyclofusional response includes a large nonmotor, or sensory, contribution. The composition of the response was unaffected by changes in stimulus size. Increased stimulus complexity elicited larger cyclotorsional eye movements and diminished the amount of perceived inclination which was observed in the fused percept.
Adult↗
Fusional response to extrafoveal stimulation.
Horizontal and vertical fusional responses to extrafoveal stimulation were examined. An objective binocular eye movement measuring technique was utilized to position an artificial, stabilized scotoma over the central 10 degrees diameter area of one eye. The responses contained both a motor and nonmotor, or sensory, component. The monocular eye movements were asymmetrical.
Eye Movements↗