June 1980
Volume 19, Issue 6
Free
Articles  |   June 1980
Visual consequences of the foveal pit.
Investigative Ophthalmology & Visual Science June 1980, Vol.19, 653-667. doi:
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      D R Williams; Visual consequences of the foveal pit.. Invest. Ophthalmol. Vis. Sci. 1980;19(6):653-667.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
This content is PDF only. Please click on the PDF icon to access.
Abstract

When viewing a uniform field through a small aperture moved circularly before the pupil of the eye, many observers report a diffuse dim spot subtending roughly 1 degree visual angle, which rolls around the fixation point in synchrony with the motion of the aperture. Measurements of the Stiles-Crawford maximum for different locations within the fovea confirm that small but systematic shifts in foveal directional sensitivity are responsible for this entoptic effect. A quantitative model is developed which accounts for the directional sensitivity shifts on the basis of refraction of light at the sloping sides of the foveal pit. Supporting evidence for the model is provided by a second entoptic phenomenon: fundal scatter from the image of a glare source on the eccentric retina is reflected by the foveal pit in such a way as to render it visible. Estimates of the slope of the foveal pit from this effect agree well with that predicted from the observed shifts in directional sensitivity.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×