title: Increased susceptibility to injury in older eyes.
abstract: OBJECTIVE
  To determine whether there is an age-dependent susceptibility in retinal function in response to repeated anterior chamber cannulation with or without intraocular pressure (IOP) elevation.
  
  
  METHODS
  Baseline electroretinograms were measured in 3- and 18-month-old Sprague-Dawley rats (n = 16 each group). Following baseline assessment, eyes were randomly assigned to undergo a 60-min anterior chamber cannulation with IOP either left at baseline (sham, 15 mm Hg) or elevated to 60 mm Hg. This was repeated three additional times, with each episode separated by 1 week. At weeks 1 to 3, dark-adapted retinal function was assessed immediately before cannulation, with final functional assessment at week 4.
  
  
  RESULTS
  Both sham and IOP elevated eyes of older rats showed retinal dysfunction, which became more pronounced with the number of repeated insults. This effect was largest for responses arising from the inner retina. Repeated insult in younger eyes did not produce a change in amplitude but an increase in the sensitivity to light of photoreceptoral and bipolar cell components of the electroretinogram.
  
  
  CONCLUSIONS
  Repeated trauma, not IOP, produces permanent retinal dysfunction in older eyes. Younger eyes appear to be able to withstand this type of injury by upregulating sensitivity of outer and middle retinal responses to maintain normal inner retinal function.
authors: Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors: Jason
authors: J
authors: Charng
authors: Christine T O
authors: CT
authors: Nguyen
authors: Algis J
authors: AJ
authors: Vingrys
authors: Andrew I
authors: AI
authors: Jobling
authors: Bang V
authors: BV
authors: Bui
mesh_terms: D000375:Aging; D000818:Animals; D000867:Anterior Chamber / Q000293:injuries; D003623:Dark Adaptation; D004195:Disease Models, Animal; D004596:Electroretinography; D005131:Eye Injuries / Q000150:complications* / Q000503:physiopathology; D007429:Intraocular Pressure; D010775:Photic Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000503:physiopathology*; D012164:Retinal Diseases / Q000209:etiology* / Q000503:physiopathology