HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by He, Z. Articles by Vingrys, A. J. Search for Related Content PubMed PubMed Citation Articles by He, Z. Articles by Vingrys, A. J.

The Rate of Functional Recovery from Acute IOP Elevation

From the Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.

PURPOSE. To evaluate the recovery of retinal function after acute IOP elevation.

METHODS. The electroretinogram (ERG) was measured before, during, and after IOP increased to 50 and 70 mm Hg at different durations in anesthetized, dark-adapted rats (n = 5–7). Signals were collected for dim and bright flashes (–4.95 and 1.0 log cd · s/m²) and analyzed in terms of the photoreceptoral (P3), postreceptoral (P2), and inner retinal (negative scotopic threshold response [nSTR]) responses. Parameters (treatment/baseline, %) were compared across time by using repeated-measures ANOVA and t-tests. The rate of recovery was quantified with a logistic function and compared by bootstrap.

RESULTS. IOP spikes induce greater loss (P < 0.01) and slower recovery (P < 0.001) in the nSTR compared with the P2 and P3 responses. IOP spikes having common integral (pressure x duration, 2100 mm Hg x minutes) for insult gave significantly greater P2 and nSTR dysfunction at the higher pressure (70 vs. 50 mm Hg, nSTR reduced to –2.5% ± 0.5% vs. 20.3% ± 6.5%, P < 0.05). The higher pressure also produced significantly slower nSTR recovery (50% recovery time [t_0.5] 70 vs. 50 mm Hg: 33.1 vs. 21.7 minutes; P < 0.05). At a given IOP (70 mm Hg), t_0.5 showed a linear relationship with duration (15 vs. 30 vs. 60 minutes’ exposure: t_0.5 16.7 vs. 33.1 vs. 63.2 minutes; P < 0.05) and integral.

CONCLUSIONS. Ganglion cell function recovers slower than the outer retina after IOP insult, with peak IOP being the principle determinant of functional loss and recovery. For a fixed pressure, functional recovery is linearly related to exposure.

This article has been cited by other articles:

				J. C. Morrison, L. Jia, W. Cepurna, Y. Guo, and E. Johnson Reliability and Sensitivity of the TonoLab Rebound Tonometer in Awake Brown Norway Rats Invest. Ophthalmol. Vis. Sci., June 1, 2009; 50(6): 2802 - 2808. [Abstract] [Full Text] [PDF]

				C. T. O. Nguyen, A. J. Vingrys, and B. V. Bui Dietary Omega-3 Fatty Acids and Ganglion Cell Function Invest. Ophthalmol. Vis. Sci., August 1, 2008; 49(8): 3586 - 3594. [Abstract] [Full Text] [PDF]

				Z. He, B. V. Bui, and A. J. Vingrys Effect of Repeated IOP Challenge on Rat Retinal Function Invest. Ophthalmol. Vis. Sci., July 1, 2008; 49(7): 3026 - 3034. [Abstract] [Full Text] [PDF]

				D J Holcombe, N Lengefeld, G A Gole, and N L Barnett Selective inner retinal dysfunction precedes ganglion cell loss in a mouse glaucoma model Br. J. Ophthalmol., May 1, 2008; 92(5): 683 - 688. [Abstract] [Full Text] [PDF]

				S. Machida, D. Raz-Prag, R. N. Fariss, P. A. Sieving, and R. A. Bush Photopic ERG Negative Response from Amacrine Cell Signaling in RCS Rat Retinal Degeneration Invest. Ophthalmol. Vis. Sci., January 1, 2008; 49(1): 442 - 452. [Abstract] [Full Text] [PDF]