Decreased ocular light penetration and electroretinographic response time.
The response time is an extremely important element of the clinical electroretinogram (ERG) with respect to the recording's clinical interpretation. It is related to the intensity of stimulation. A series of simple experiments was devised in which light penetration to the retina was impaired. We expected simple and straightforward results, with all situations resulting in a decreased effective intensity of stimulation. It seems, however, that different types of decreased ocular light penetration may have different effects on ERG sensitivity and response time. When light penetration to the retina is decreased by filters the peak time is normal at the threshold (50 microV) and the sensitivity is decreased. Miosis produces quite a different picture:both the peak time at the threshold and the sensitivity are decreased. The results with miosis are similar to those obtained with models of photoreceptor destruction. Vitreous hemorrhages seem to act, according to the amount and diffusion of blood, either as filters or by producing a focal loss of photoreceptor function.
D000818:Animals; D004596:Electroretinography / Q000379:methods*; D008027:Light; D008916:Miotics / Q000494:pharmacology; D055095:Optics and Photonics; D055585:Physical Phenomena; D010825:Physics; D011680:Pupil / Q000187:drug effects; D011817:Rabbits; D012160:Retina / Q000502:physiology*; D013997:Time Factors; D014822:Vitreous Body
D008916:Miotics