Document Detail

Evidence supportive of a functional discrimination between photopic oscillatory potentials as revealed with cone and rod mediated retinopathies.
MedLine Citation:
PMID:  10189180     Owner:  NLM     Status:  MEDLINE    
We report on a family where four of the eleven children presented with reduced visual acuities, a red-green deficit at the Farnsworth-Munsel FM 100-hue test, normal appearing fundi and unexpected electroretinographic findings. Light- (photopic) and dark- (scotopic) adapted electroretinograms (ERG) and oscillatory potentials (OPs) were obtained following an accepted standard protocol. The b-wave of their photopic ERG was significantly more attenuated than the a-wave due to the specific abolition of OP4, while the amplitudes of OP2 and OP3 were within the normal range, giving to the b-wave a truncated appearance reminiscent of that seen in congenital stationary night blindness (CSNB) with myopia. Interestingly in the latter condition, which is believed to result from an ON-retinal pathway anomaly, it is OP2 and OP3 which are specifically abolished while OP4 is of normal amplitude thus resulting in an OP response pattern which complements that seen with our patients. Also of interest is the fact that, in our patients, the amplitude of the dark-adapted OP2 was, on average, 240% larger than that measured in light-adaptation while, in normal, a non-significant 14% increase is noted; a finding which is in keeping with other studies reporting supernormal scotopic ERGs in some forms of cone dystrophies. Based on the photopic OP response pattern, our patients represent the electrophysiological complement of patients affected with CSNB. Interestingly their symptoms are also complementary, a finding which could support a functional discrimination between the photopic OPs.
P Lachapelle; S Rousseau; M McKerral; J Benoit; R C Polomeno; R K Koenekoop; J M Little
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Documenta ophthalmologica. Advances in ophthalmology     Volume:  95     ISSN:  0012-4486     ISO Abbreviation:  Doc Ophthalmol     Publication Date:  1998  
Date Detail:
Created Date:  1999-05-03     Completed Date:  1999-05-03     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370667     Medline TA:  Doc Ophthalmol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  35-54     Citation Subset:  IM    
Department of Ophthalmology, McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.
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MeSH Terms
Child, Preschool
Dark Adaptation
Fluorescein Angiography
Fundus Oculi
Myopia / congenital,  genetics,  physiopathology
Night Blindness / congenital,  genetics,  physiopathology
Photic Stimulation
Retinal Cone Photoreceptor Cells / pathology,  physiopathology*
Retinal Degeneration / diagnosis,  genetics,  physiopathology*
Retinal Rod Photoreceptor Cells / pathology,  physiopathology*

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