Contour integration in peripheral vision reduces gradually with eccentricity.
Hess and Dakin reported that normally-sighted subjects using peripheral vision (beyond 10 degrees ) were unable to detect paths of alternating-phase Gabors embedded within randomly positioned Gabors, but could detect same-phase paths. This result led them to propose a "fundamental difference" between central and peripheral visual processing. While we were able to replicate many of their results, our normally-sighted observers could detect alternating-phase paths beyond 10 degrees. We found that path detection decreased monotonically as a function of eccentricity (0 degrees -30 degrees ) for both alternating-phase and same-phase stimuli. As with most visual functions the more difficult path detection condition (alternating-phase) declined slightly faster. The results for the normally-sighted observers could not be explained by poor fixation. Three people with substantial central vision loss (i.e. they can only use peripheral vision) could see both same- and alternating-phase stimuli with eccentric viewing of 13 degrees -17 degrees. Therefore central and peripheral vision appear to use similar visual mechanisms to perform the task, there being no fundamental difference.
Nugent
Alex K
AK
The Schepens Eye Research Institute, Harvard Medical School, Boston, MA 02114-2500, USA.
Keswani
Rajesh N
RN
Woods
Russell L
RL
Peli
Eli
E
D000328:Adult; D005556:Form Perception / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D011601:Psychophysics; D012607:Scotoma / Q000503:physiopathology*; D013028:Space Perception / Q000502:physiology*; D014787:Vision Tests; D014792:Visual Acuity; D014794:Visual Fields