Purchase this article with an account.
B. Khoobehi, H. Kawano, J.–F. Ning, F. Khan, C.F. Burgoyne, H.W. Thompson, J.M. Beach; Oxygen Depletion in Retina Artery–Vein Pairs and Optic Nerve Head (ONH) Tissues Using Hyperspectral Imaging . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2375.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To use a non–invasive hyperspectral imaging (HSI) method to evaluate the oxygen saturation of the ONH tissues and retinal artery–vein pairs during acute intraocular pressure elevation. Methods:Five cynomolgus monkeys with normal eyes were used. Intraocular pressure was set to 10, 30, 45, and 55 mm Hg in both eyes of each monkey and three fundus hyperspectral images were obtained after 10 minutes and three more after 30 minutes at each pressure. Three compliance tests were performed before and after the hyperspectral imaging sessions using the Heidelberg Retinal Tomograph–II to document the baseline and post–experimental condition of the ONH and vessels. Blood pressure was measured periodically throughout the procedure. The data were analyzed using a nested analysis of variance (ANOVA). Results:A comparison of the compliance test results obtained before and after the HSI experiments revealed no damage to the ONH due to acute intraocular pressure elevations. The relative saturation index (RSI) values calculated from the hyperspectral imaging data showed the following: 1) Changes in oxygen saturation within the arteries as intraocular pressure increased from 10 to 30 mm Hg were not significant. However, oxygen saturation was decreased significantly (P < 0.0001) at 45 and 55 mm Hg. 2) Significant desaturation was found within the veins at 30, 45, and 55 mm Hg , compared with 10 mm Hg (P < 0.0001). 3) ONH tissues (superior, nasal, temporal, and cup areas) showed no significant changes at intraocular pressures of 30 and 45 mmHg, compared with 10 mm Hg, although some tendency toward significance was seen in the inferior region (P = 0.0052). All regions of the ONH tissues showed significant changes at 55 mmHg (P < 0.0001). There were no differences in the results at 10 minutes and 30 minutes in any tissue at any intraocular pressure. Conclusions: The results of this study suggest the autoregulatory mechanisms that control oxygen saturation are different in the retinal vessels and ONH tissues.
This PDF is available to Subscribers Only