We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
ERG findings in three hypothyroid adult dogs with and without levothyroxine treatment.
- Authors
Durieux, Philippe; Rigaudière, F.; LeGargasson, J.-F.; Rosolen, S. G.
- Abstract
Purpose To evaluate the effects of levothyroxine (LTh) on the electroretinogram (ERG) of adult dogs. Material and methods Binocular, full field photopic and scotopic ERGs were recorded from an anesthetized Maltese Bichon cross (MB), a Yorkshire Terrier (YT) and a Shetland Sheepdog (SS) affected with hypothyroidism and treated with a daily dose of LTh at 20 µg/kg. The photopic ERGs were evoked to 12 different intensities ranging from 0.81 to –2.19 log cd.s/m2 and presented under photopic conditions in order to assess (from the derived luminance-response curves) Vmax and b : a amplitude ratio parameters. Photopic flicker ERGs were obtained at 30 Hz. The scotopic ERGs (intensity: –3.09 log cd.s/m2) were recorded while the retina was dark-adapting and after 32 min of dark adaptation. This procedure was performed on two separate sessions: following a 3-day interruption of LTh treatment (S1) and following 30 days without interruption of LTh treatment (S2). Results The mean photopic a-wave peak times were 9.8 ms at S1 and 5.0 ms at S2, respectively. The mean photopic b-wave peak times were 23.3 ms at S1 and 11.5 ms at S2, respectively, and the mean scotopic b-wave peak times (after 32 min of dark adaptation) were 45.2 ms at S1 and 26.0 ms at S2, respectively. No other significant ERG changes were observed. Conclusion Our results indicate that a dose of 20 µg/kg of LTh given to adult dogs was accompanied by a marked peak time shortening of both photopic and scotopic ERGs, without affecting other ERG parameters.
- Subjects
ELECTRORETINOGRAPHY; ELECTRODIAGNOSIS; EYE examination; YORKSHIRE terrier; SHETLAND sheepdog
- Publication
Veterinary Ophthalmology, 2008, Vol 11, Issue 6, p406
- ISSN
1463-5216
- Publication type
Article
- DOI
10.1111/j.1463-5224.2008.00656.x