TY - JOUR
T1 - Measurement of Optic Disc Compliance by Digitized Image Analysis in the Normal Monkey Eye
AU - Burgoyne, Claude F.
AU - Quigley, Harry A.
AU - Thompson, Hilary W.
AU - Vitale, Susan
AU - Varma, Rohit
N1 - Funding Information:
Presented in part at the Association for Research in Vision and Ophthalmology Annual Meeting, Sarasota, Florida, May 4, 1994. Supported in part by U.S. Public Health Service grants F32EY07047 (Dr. Burgoyne), ROIEY02120 (Dr. Quigley), F32EY06536 (Dr. Varma), P30EYOl765 (Wilmer Institute Core Facility), and P30EY02377 (LSU Eye Center Core Facility) from the National Eye Institute, Bethesda, Maryland; RR04060 (Shared Instrumentation Grant) from the National Institutes of Health; a grant from National Glaucoma Research, a program of the American Health Assistance Foundation, Rockville, Maryland; and instrumentation support from the Topcon Corporation. Dr. Burgoyne is the recipient of a Career Development Award (1994-1998) from Research to Prevent Blindness, New York, New York.
PY - 1995
Y1 - 1995
N2 - Purpose: To characterize the compliance of the normal monkey optic disc under conditions of induced short-term fluctuations in intraocular pressure (IOP). Methods: In 10 monkeys, one eye was compliance tested on three separate days followed by a single test of the contralateral eye (40 compliance tests). In a testing session, the optic disc was imaged at 2 and 47 minutes (baseline time point) after IOP was lowered to 10 mmHg; then at 2, 17, 32, and 47 minutes after IOP was elevated to 45 mmHg; then at 2, 47, and, in some cases, 92 minutes after IOP was lowered back to 10 mmHg. Eight digitized images were analyzed at each time point, yielding two parameters to characterize the position of the disc: the Mean Position of the Disc(MPD) and the Change from MPDBaseline(the value of MPD at a given time point minus the value for MPD at the baseline time point of that testing session). Analysis of variance (ANOVA) testing was used to evaluate the overall effect of IOP on both parameters while taking into account the effects of variability due to different monkeys and repetitions of the test as well as differences between the two eyes of an individual monkey. With the addition of data from 11 compliance tests performed on eight additional monkeys, the overall results were calculated in terms of the mean Change from MPDBaselineat each time point for a total of 51 compliance testing sessions. Results: The mean Change from MPDBaselinewas -28 μm (95% confidence interval, -23 to -33 μm) 47 minutes after elevation of IOP. The disc surface returned to its baseline position 92 minutes after IOP was lowered back to 10 mmHg. Elevation of IOP within a compliance test had a significant effect on the position of the optic disc surface (P= 0.0002, ANOVA), as characterized by the parameter Change from MPDBaseline-Neither the difference in the amount of movement between -the two eyes of an individual monkey nor the variability within the three repetitions of the test in a given eye was statistically significant. Conclusion: Small, reversible (elastic) posterior deformations of the optic disc surface follow acute elevations of IOP in the normal monkey eye. Detection of acute IOP-induced deformations of the optic disc surface may represent a means by which to mechanically test the deeper load-bearing tissues of the optic nerve head.
AB - Purpose: To characterize the compliance of the normal monkey optic disc under conditions of induced short-term fluctuations in intraocular pressure (IOP). Methods: In 10 monkeys, one eye was compliance tested on three separate days followed by a single test of the contralateral eye (40 compliance tests). In a testing session, the optic disc was imaged at 2 and 47 minutes (baseline time point) after IOP was lowered to 10 mmHg; then at 2, 17, 32, and 47 minutes after IOP was elevated to 45 mmHg; then at 2, 47, and, in some cases, 92 minutes after IOP was lowered back to 10 mmHg. Eight digitized images were analyzed at each time point, yielding two parameters to characterize the position of the disc: the Mean Position of the Disc(MPD) and the Change from MPDBaseline(the value of MPD at a given time point minus the value for MPD at the baseline time point of that testing session). Analysis of variance (ANOVA) testing was used to evaluate the overall effect of IOP on both parameters while taking into account the effects of variability due to different monkeys and repetitions of the test as well as differences between the two eyes of an individual monkey. With the addition of data from 11 compliance tests performed on eight additional monkeys, the overall results were calculated in terms of the mean Change from MPDBaselineat each time point for a total of 51 compliance testing sessions. Results: The mean Change from MPDBaselinewas -28 μm (95% confidence interval, -23 to -33 μm) 47 minutes after elevation of IOP. The disc surface returned to its baseline position 92 minutes after IOP was lowered back to 10 mmHg. Elevation of IOP within a compliance test had a significant effect on the position of the optic disc surface (P= 0.0002, ANOVA), as characterized by the parameter Change from MPDBaseline-Neither the difference in the amount of movement between -the two eyes of an individual monkey nor the variability within the three repetitions of the test in a given eye was statistically significant. Conclusion: Small, reversible (elastic) posterior deformations of the optic disc surface follow acute elevations of IOP in the normal monkey eye. Detection of acute IOP-induced deformations of the optic disc surface may represent a means by which to mechanically test the deeper load-bearing tissues of the optic nerve head.
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U2 - 10.1016/S0161-6420(95)30792-0
DO - 10.1016/S0161-6420(95)30792-0
M3 - Article
C2 - 9098279
AN - SCOPUS:0029591329
SN - 0161-6420
VL - 102
SP - 1790
EP - 1799
JO - Ophthalmology
JF - Ophthalmology
IS - 12
ER -