IOVS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

(Investigative Ophthalmology and Visual Science. 2006;47:3220-3224.)
© 2006 by The Association for Research in Vision and Ophthalmology, Inc.
DOI:  10.1167/iovs.05-1252
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Good, W. V.
Right arrow Articles by Hou, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Good, W. V.
Right arrow Articles by Hou, C.

Sweep Visual Evoked Potential Grating Acuity Thresholds Paradoxically Improve in Low-Luminance Conditions in Children with Cortical Visual Impairment

William V. Good and Chuan Hou

From the Smith Kettlewell Eye Research Institute, San Francisco, California.

PURPOSE. Children with cortical or cerebral visual impairment (CVI) often experience photophobia. In a study conducted to test whether this clinical phenomenon affects visual function, the sweep visual evoked potential (VEP) was used to evaluate cortical responses to grating stimuli in two luminance conditions: low and normal.

METHODS. Twenty children (age range, 7 months to 4 years 10 months) with CVI and 17 age-matched control subjects were examined. Testing conditions consisted of a swept grating stimulus shown against a normal background luminance (109 cd/m2) and against a low-luminance background (20 cd/m2). Thresholds in these two luminance conditions were compared. Response amplitudes across the spatial frequency domain were also compared.

RESULTS. Children with CVI paradoxically have improved grating acuity thresholds when the stimulus is shown using a low-luminance background (P = 0.006). Response amplitudes are also increased in low luminance. In control children, luminance had no significant effect on response amplitudes or thresholds.

CONCLUSIONS. Increased luminance causes a worsening of acuity thresholds in children with CVI. Response amplitudes are also diminished in normal luminance. This finding has implications for optimal viewing and learning conditions for children with CVI.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2006 by the Association for Research in Vision and Ophthalmology