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Graefes Arch Clin Exp Ophthalmol. 2007 Sep;245(9):1335-45. Epub 2007 Jan 31.

Oscillatory potentials and the b-Wave: partial masking and interdependence in dark adaptation and diabetes in the rat.

Author information

1
Nuffield Laboratory of Ophthalmology, Oxford University, Walton St, Oxford OX2 6AW, UK. chris.layton@laytonvision.com.au

Abstract

BACKGROUND:

Diabetes inhibits dark adaptation and both processes alter the electroretinogram (ERG) in similar ways. This study aimed to investigate the relationship between oscillatory potentials (OPs) and the b-wave during dark adaptation and to determine if this relationship changes during the development of diabetes.

METHODS:

Twenty-one rats were assigned to adaptation, control and diabetic groups. Rats were dark adapted for periods between 20 minutes and 4 hours, and ERGs recorded. Diabetes was induced with streptozotocin, and ERGs measured after 3, 6, 9 and 12 weeks after injection.

RESULTS:

Increasing periods of dark adaptation led to a logarithmic increase in the amplitude of the b-wave and the OPs. This was accompanied by a decrease in the peak times of the OPs and b-wave. Total OP amplitude and b-wave amplitude were linearly related, allowing an empirical OP constant to be developed to describe the relationship between the two parameters. Diabetes led to a progressive decrease in the amplitude and increase in the peak time of all waves. The OP constant decreased in a linear fashion with increasing duration of diabetes.

CONCLUSIONS:

It is argued that OP masking of the b-wave could explain previous inconsistencies in reported ERG changes in diabetes and that a slowing of dark adaptation does not account for these ERG changes. The report concludes that the OPs and b-wave amplitudes and latencies are intimately related in the normal retina and that this correlation is lost predictably during the development of diabetes.

PMID:
17265029
DOI:
10.1007/s00417-006-0506-0
[Indexed for MEDLINE]

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