We investigated the effects of early monocular enucleation (ME) (surgical removal of one eye) on a high-level spatial visual ability, namely face perception. Early monocular deprivation of pattern vision from disorders such as strabismus, amblyopia, or cataract is associated with impairments in low-level spatial vision. This is inconsistent with studies of early ME that show either equivalent or enhanced low-level spatial vision compared with controls. Impairments on some aspects of face perception (i.e., feature-spacing and holistic face processing, both of which mature later in life) have been found with early pattern deprivation from congenital cataract. It is not clear whether the intact low-level spatial vision with ME will also persist with high-level face perception or whether deficits similar to those found with cataract will emerge.
We tested individuals who have experienced early ME and controls on a series of high-level spatial visual tasks that measure feature-spacing, feature, and holistic face processing.
The ME group were slower for feature spacing and feature tasks. Furthermore, the ME group did not exhibit the normal pattern of poorer performance on the aligned compared with misaligned composite face discrimination tasks, demonstrating a lack of the composite face effect. However, they did show the normal pattern of poorer performance on same vs. different trials on the aligned tasks.
These results indicate an impairment in the feature spacing and feature aspects of face perception with ME. They also suggest a present yet, incomplete, development of holistic face processing in this group. Although the complete removal of inhibitory binocular interactions and/or the absence of binocular competition in early ME may result in cortical reorganization of the visual system and preserve low- to mid-level spatial vision, it may be insufficient for the maturation of high-level face perception.
Centre for Vision Research, York University (KRK, JKES), Department of Psychology (KRK, JKES), York University, and Ophthalmology and Cancer Informatics, University Health Network, University of Toronto (BLG), Toronto, Ontario, Canada.
This research was supported by grants from the Banting Research Foundation, the Canadian National Institute for the Blind (CNIB), the Canada Foundation for Innovation (CFI), and the Natural Sciences and Engineering Council (NSERC) of Canada (to JKES), and an Ontario Graduate Scholarship in Science and Technology (to KRK).
Received January 3, 2011; accepted October 12, 2011.
Krista Kelly; Centre for Vision Research and Department of Psychology; York University; 4700 Keele Street; Toronto, Ontario M3J 1P3; Canada; e-mail: firstname.lastname@example.org