C J Layton1, R Safa, N N Osborne. 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.
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.
Authors: N Hotta; N Koh; F Sakakibara; J Nakamura; T Hara; Y Hamada; H Fukasawa; H Kakuta; N Sakamoto Journal: Eur J Pharmacol Date: 1997-05-12 Impact factor: 4.432
Authors: N Hotta; N Koh; F Sakakibara; J Nakamura; Y Hamada; T Hara; K Mori; E Nakashima; K Naruse; H Fukasawa; H Kakuta; N Sakamoto Journal: Diabetes Date: 1996-03 Impact factor: 9.461
Authors: Machelle T Pardue; Claire S Barnes; Moon K Kim; Moe H Aung; Raj Amarnath; Darin E Olson; Peter M Thulé Journal: Transl Vis Sci Technol Date: 2014-06-19 Impact factor: 3.283