Foveal Cysts

Using Foveal

Foveal tritanopia.

Measurements of sensitivity and color discrimination suggest that an area roughly 25’ in diameter in the central fovea lacks functioning blue-sensitive cones. Alternative explanations such as screening by macular pigment or Troxler fading are shown to be unable to account for the results. Evidence is presented that residual B cone-mediated color discrimination found in this and previous studies...

Foveal and extra-foveal influences on rod hue biases.

Green, blue and short-wavelength-red rod hue biases are strongest and most reliable with large, dimly-mesopic, extra-foveal stimuli but tend to diminish when stimuli are confined to a small area of the central fovea. This study explores how the stimulation of foveal and extra-foveal areas interact in determining rod hue biases, and whether large stimuli are as effective for revealing rod hue bi...

Discriminating mirror symmetry in foveal and extra-foveal vision

The ability to discriminate perfect from imperfect mirror symmetry was examined at the fovea and at eccentricities out to 10 degrees in the nasal visual field. A 2-AFC method of constant stimuli was employed in which a bilaterally symmetric pattern was presented in one interval and a degraded version of this symmetric pattern in the other. The subject's task was to decide which interval contain...

Is delayed foveal feedback critical for extra-foveal perception?

Recent neuroimaging evidence suggests that visual inputs arising beyond the fovea can be 'fed back' to foveal visual cortex to construct a new retinotopic representation. However, whether these representations are critical for extra-foveal perception remains unclear. Using transcranial magnetic stimulation we found that relatively late (350-400 msec) disruption of foveal retinotopic cortex impa...