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Spatial contrast sensitivity vision loss in children with cortical visual impairment
William V Good1, Chuan Hou, Anthony M Norcia
1Smith-Kettlewell Eye Research Institute, San Francisco, California 94115, USA.
Investigative Ophthalmology & Visual Science
|October 13, 2012
Summary
Cortical visual impairment (CVI) significantly reduces contrast sensitivity and grating acuity in children. These visual functions are diminished compared to typically developing peers, highlighting contrast sensitivity as a key diagnostic measure.
Area of Science:
- Ophthalmology
- Pediatric Neuroscience
- Visual Electrophysiology
Background:
- Cortical visual impairment (CVI) is a primary cause of vision impairment in children in Western nations.
- Understanding the specific impacts of CVI on visual function remains limited.
Purpose of the Study:
- To compare contrast sensitivity and grating acuity using visual evoked potential (VEP) measures in children with CVI and typically developing controls.
- To quantify deficits in visual function associated with CVI.
Main Methods:
- Utilized swept parameter visual evoked potential (sVEP) to assess contrast sensitivity and grating acuity.
- Measured contrast and spatial frequency thresholds in 34 children with CVI (5 months–5 years) and 16 age-matched controls.
- Compared threshold values and maximal response amplitudes between the CVI and control groups.
Main Results:
- Children with CVI exhibited significantly reduced contrast sensitivity (median 10.8%) and grating acuity (median 0.49 logMAR).
- The majority of children with CVI (30/34) showed measurable but impaired contrast sensitivity, and (32/34) impaired grating acuity.
- Response amplitudes were significantly diminished across all sweep ranges in children with CVI compared to controls.
Conclusions:
- Spatial contrast sensitivity and VEP response amplitudes are demonstrably impacted by CVI.
- The significant loss in contrast sensitivity suggests its utility as a sensitive metric for assessing visual deficits in CVI patients.
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