OUR UNDERSTANDING of events in the normal and diseased optic fundus would be aided if it were possible to measure the retinal oxygen tension.The retina has a high rate of oxygen consumption.Its vessels nor- mally change caliber in response to a change in arterial blood oxygen tension, dilating wrhen the tension falls and constricting when it rises." 2 This suggests that shifts in retinal oxygen tension are opposed by appropriate changes in blood flow.In patients with hyper- tension or diabetes the retinal vessels are gen- erally less responsive to change in arterial blood oxygen.3-5Some of the retinal changes that occur in these and other disorders, such as hemorrhages, cotton-wool exudates, and neo-vascularization, appear to be caused by retinal hypoxia or ischemia.To facilitate the study of such phenomena we have d'evised a photographic method for estimating in man the per cent oxygen satura- tion of retinal venous blood, as an index of the over-all retinal oxygen tension.It is the purpose of this report to describe the method and its validation, and to present information obtained from its use in normal subjects.Cer- tain of the early results obtained with early versions of the method have been summarized briefly elsewhere.6Method Principle of the Method The method is like other photometric proce- dures for estimation of blood oxygen saturation in measuring the relative intensity at different From the Department of Medicine and the Heart
No takes yet. Share an insight, caveat, or question.
Hickam et al. (1963) studied this question.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: