The long term objective of this proposal is the investigation with noninvasive techniques of the physiology of the retinal, optic nerve head and choroidal circulation and the role played by these circulations in the development of ocular fundus diseases. In the period of this grant, we will: a) develop laser Doppler velocimetry (LDV) methods to measure velocity, volume and flow of blood in the optic nerve head and choroidal circulations that are applicable in human subjects; b)investigate the physiology of these circulations, specifically the blood flow regulation in response to various physiological stresses such as hyperoxia, hypercapnia and moderate changes in ocular perfusion pressure; c) investigate the regulation of peripheral and macular retinal blood flow (RBF) in response to changes in fundus illumination; d) investigate retinal hemodynamics in early diabetes mellitus to determine whether it is abnormal in diabetic patients without retinopathy; e) investigate whether diabetic eyes with or without each of the following: serve capillary non perfusion, NVD, NVE and vitreous hemorrhage have RBF and RBF response to hyperoxia are different; f) investigate the potential of infrared LDV to localize neovascular membranes in age related macular degeneration. It is expected that these studies will increase our understanding of the ocular fundus circulation and of the microvascular pathophysiology in diabetic retinopathy. The development of noninvasive techniques to measure optic nerve and choroidal circulation may ultimately help substantiate or dismiss the vasogenic theory of glaucoma.
| Riva, C E; Cranstoun, S D; Petrig, B L (1996) Effect of decreased ocular perfusion pressure on blood flow and the flicker-induced flow response in the cat optic nerve head. Microvasc Res 52:258-69 |
| Grunwald, J E; DuPont, J; Riva, C E (1996) Retinal haemodynamics in patients with early diabetes mellitus. Br J Ophthalmol 80:327-31 |
| Portellos, M; Riva, C E; Cranstoun, S D et al. (1995) Effects of adenosine on ocular blood flow. Invest Ophthalmol Vis Sci 36:1904-9 |
| Mann, R M; Riva, C E; Stone, R A et al. (1995) Nitric oxide and choroidal blood flow regulation. Invest Ophthalmol Vis Sci 36:925-30 |
| Vo Van Toi; Riva, C E (1995) Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats. J Physiol 482 ( Pt 1):189-202 |
| Riva, C E; Cranstoun, S D; Grunwald, J E et al. (1994) Choroidal blood flow in the foveal region of the human ocular fundus. Invest Ophthalmol Vis Sci 35:4273-81 |
| Riva, C E; Cranstoun, S D; Mann, R M et al. (1994) Local choroidal blood flow in the cat by laser Doppler flowmetry. Invest Ophthalmol Vis Sci 35:608-18 |
| Scheiner, A J; Riva, C E; Kazahaya, K et al. (1994) Effect of flicker on macular blood flow assessed by the blue field simulation technique. Invest Ophthalmol Vis Sci 35:3436-41 |
| Grunwald, J E; Brucker, A J; Grunwald, S E et al. (1993) Retinal hemodynamics in proliferative diabetic retinopathy. A laser Doppler velocimetry study. Invest Ophthalmol Vis Sci 34:66-71 |
| Pakola, S J; Grunwald, J E (1993) Effects of oxygen and carbon dioxide on human retinal circulation. Invest Ophthalmol Vis Sci 34:2866-70 |
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