Amblyopia reduces temporal, not just spatial resolution
Karoline Spang 1
and
Manfred Fahle 1*
1 Human Neurobiology, Bremen University, Bremen, Germany
* To whom correspondence should be addressed. E-mail: mfahle{at}uni-bremen.de.
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Abstract |
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Purpose: In amblyopia, neuronal deficits deteriorate spatial vision including visual acuity - possibly due to a lack of use-dependent fine-tuning of afferents to the visual cortex during infancy. But temporal processing might be deteriorated, too. Methods: We investigated the temporal, rather than spatial resolution of amblyopic patients by means of a task based on time-defined figure-ground segregation. Patients had to indicate the quadrant of the visual field where a purely time-defined square appeared. Results: The results show a clear decrease of temporal resolution of patients' amblyopic eyes compared to the dominant eyes in this task. The extend of this decrease in figure-ground segregation based on time of motion onset only loosely correlates with the decrease in spatial resolution and spans a smaller range than the spatial loss. Control experiments with artificially induced blur in normal observers confirmed that the decrease of temporal resolution is not simply due to the acuity loss. Conclusions: We conclude that amblyopia not only decreases spatial resolution, but also temporal factors such as time-based figure-ground segregation even at high stimulus contrasts. This finding requires to extend the realm of neuronal processes that may be disturbed in amblyopia.
Key Words:
amblyopia, psychophysics, motion perception
