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Paul Miller, Derek Arnold; Reducing the size of the human blind spot through training.. Journal of Vision 2015;15(12):1300. doi: 10.1167/15.12.1300.
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© 2017 Association for Research in Vision and Ophthalmology.
Some research suggests that visual training in and around regions of insensitivity due to cortical scotomas can result in recovery of function. Such reports are controversial, and have been criticized for inadequate control of eye movements. We reasoned that some improvement through training was plausible, if the brain can adjust gains for still-functioning neurons in relation to input in and around regions of insensitivity. This emphasizes a functional definition of insensitivity, rather than insensitivity being set by the number and distribution of functional neurons. Accordingly, we reasoned that one might be able to improve performance around a region of insensitivity that all sighted people share – the human blind spot. All tasks involved size threshold estimation. Stimuli were presented in annuli with a diameter adjusted according to a 1-up 2-down staircase procedure while we recorded eye movements. For four weeks people trained daily on a motion-direction discrimination task at the periphery of the blind spot in one eye. Comparisons of performance pre and post-training revealed a disproportionate improvement for the trained blind spot, relative to the untrained blind spot, ruling out an explanation based on a generic practice effect. Improved sensitivity generalized to other tasks, including a color discrimination and a naturalistic speeded detection task, wherein participants had to spot a car moving out of their blind spot. These improvements could not be attributed to eye movements. Our results show that functionally defined regions of insensitivity, including the human blind spot, can be reduced through training. This offers an opportunity to develop effective protocols in normally sighted people, which could have clinical application.
Meeting abstract presented at VSS 2015
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