Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB214

Poster Communications

Retinal oxygen levels in the eye are different in macular area of the retina compared to periphery of the retina

O. B. Olafsdottir1,2, S. Hardarson1, E. Stefánsson2

1. Department of Medicine, University of Iceland, Reykjavik, Iceland. 2. Department of Ophthalmology, Landspitali University Hospital, Reykjavik, Iceland.

  • Figure demonstrates how a single arteriole (denoted with red color) or venule (denoted with green color) from the macula were compared to a single arteriole or venule from peripheral areas.

Ischemic eye retinopathies have shown topographical patterns and the macula is preferentially affected in many eye diseases such as in diabetic macular edema and age related macular degeneration. We examine topographical aspects of retinal oxygen metabolism in the hope that these may underlie the topographical expression of ischemic retinal disease. The purpose of the study was therefore to evaluate the macular oxygen metabolism and compare to other, peripheral parts of the retina. Retinal vessel oxygen saturation and vessel diameter was measured with a retinal oximeter (Oxymap T1, Oxymap ehf., Reykjavik, Iceland) in healthy individuals. Analyzed vessels were categorized as either macular vessels or peripheral vessels (all in the temporal side of the retina, see Figure). In all, 16 arterioles and 21 venules were analysed. Statistical analysis was performed with a paired t-test. The results show that retinal oxygen saturation was higher in macular venous branches (72.1±4.5%, mean±standard deviation) compared to peripherial branches (61.0±9.1%, p<0.0001). Arteriovenous difference was lower in macular vessels (19.0±6.5%) compared to peripheral vessels (29.1±8.3%, p<0.002). There was no difference between areas in oxygen saturation in arterioles (p=0.3). There was also no difference in vessel diameter between areas (p=0.5-0.7). According to the data, oxygen saturation is dramatically different in macular vessels compared to peripheral branches. This suggests substantial differences in oxygen metabolism between the macula and peripheral parts of the retina. The next step is to see whether these differences play a role in disease patterns and why the macula is so susceptible to diseases.

Where applicable, experiments conform with Society ethical requirements