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ERGs, cone-isolating VEPs and analytical techniques in children with cone dysfunction syndromes
John P Kelly1, Michael A Crognale, Avery H Weiss
1Division of Ophthalmology, Children's Hospital & Regional Medical Center, Seattle, WA 98105, USA. jkelly@chmc.org
Documenta Ophthalmologica. Advances in Ophthalmology
|May 10, 2003
Summary
Visual evoked potentials (VEPs) offer a sensitive, objective method for assessing cone photoreceptor function in children with inherited retinal diseases. This technique aids in early detection of cone loss, especially when electroretinogram (ERG) testing is not feasible.
Area of Science:
- Ophthalmology
- Neuroscience
- Genetics
Background:
- Congenital and acquired cone disorders significantly impact visual function in children.
- Standard diagnostic tools like electroretinograms (ERGs) and color vision tests are crucial but have limitations.
Purpose of the Study:
- To evaluate the efficacy of visual evoked potentials (VEPs) in assessing photoreceptor and post-receptoral function in children with cone disorders.
- To compare VEPs with full-field ERGs for diagnosing cone dysfunction syndromes.
Main Methods:
- Utilized transient visual evoked potentials (VEPs) with stimuli targeting specific cone types (L-, M-, S-cones) and post-receptoral pathways.
- Analyzed VEP signal-to-noise ratios (S/N) using Fourier analysis.
- Compared VEP results with clinical findings and ERG data in rod monochromats (RM) and cone dystrophy (CD) patients.
Main Results:
- All rod monochromat (RM) patients exhibited extinguished cone ERGs.
- A blue-cone rod monochromat showed a normal S-cone VEP, while incomplete RMs had low-level VEP signals.
- Cone dystrophy (CD) patients displayed reduced ERGs and abnormal VEPs across all cone-isolating stimuli.
Conclusions:
- Color VEPs provide a more sensitive objective assessment of macular cone function in children with cone dysfunction syndromes than standard full-field ERGs.
- VEP techniques are valuable for early detection of cone loss, particularly in pediatric patients who cannot tolerate ERG testing.