Much attention has been given to the roles of aqueous humor production and transtrabecular outflow in the maintenance of the steady-state intraocular pressure. However, it has been found that uveoscleral outflow also may play a considerable part in the IOP lowering effects of certain glaucoma treatments. Since there had not been any non-invasive method to quantitate uveoscleral outflow, an investigation of uveoscleral outflow was impossible in humans. Recently, we have reported a fluorophotometric method to determine uveoscleral outflow and true trabecular outflow facility, which is non-invasive, and can be used repetitively in animals and humans - clearly a great advantage in glaucoma research. This method to determine true trabecular outflow facility avoids pseudofacility which is inherent in previous methods. To further establish the validity and reliability of our method, comparisons will be made in monkeys between the obtained values of uveoscleral outflow and trabecular outflow facility and those obtained using invasive procedures. A basic assumption of the fluorophotometric method, that acetazolamide and timolol do not affect uveoscleral outflow and episcleral venous pressure will also be tested. In humans, the fluorophotometric method will be used to study the roles of uveoscleral outfloW, true trabecular outflow facility, and aqueous humor production in the ocular hypotensive effects of topical epinephrine, topical prostaglandins, therapeutic ultrasound, and cyclodialysis. lt is hoped that these studies will lead to a better understanding of the basic mechanisms of action of these treatments and to more effective management of glaucoma.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY007836-05
Application #
3264916
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1990-08-01
Project End
1993-11-30
Budget Start
1991-12-01
Budget End
1993-11-30
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Nebraska Medical Center
Department
Type
Schools of Medicine
DUNS #
City
Omaha
State
NE
Country
United States
Zip Code
68198
Wang, Yun-Liang; Hayashi, Mieko; Yablonski, Michael E et al. (2002) Effects of multiple dosing of epinephrine on aqueous humor dynamics in human eyes. J Ocul Pharmacol Ther 18:53-63
Toris, Carol B; Koepsell, Scott A; Yablonski, Michael E et al. (2002) Aqueous humor dynamics in ocular hypertensive patients. J Glaucoma 11:253-8
Wang, Y L; Toris, C B; Zhan, G et al. (1999) Effects of topical epinephrine on aqueous humor dynamics in the cat. Exp Eye Res 68:439-45
Toris, C B; Yablonski, M E; Wang, Y L et al. (1999) Aqueous humor dynamics in the aging human eye. Am J Ophthalmol 127:407-12
Toris, C B; Camras, C B; Yablonski, M E et al. (1997) Effects of exogenous prostaglandins on aqueous humor dynamics and blood-aqueous barrier function. Surv Ophthalmol 41 Suppl 2:S69-75
Toris, C B; Gleason, M L; Camras, C B et al. (1995) Effects of brimonidine on aqueous humor dynamics in human eyes. Arch Ophthalmol 113:1514-7
Toris, C B; Yablonski, M E; Wang, Y L et al. (1995) Prostaglandin A2 increases uveoscleral outflow and trabecular outflow facility in the cat. Exp Eye Res 61:649-57
Toris, C B; Tafoya, M E; Camras, C B et al. (1995) Effects of apraclonidine on aqueous humor dynamics in human eyes. Ophthalmology 102:456-61
Toris, C B; Camras, C B; Yablonski, M E (1993) Effects of PhXA41, a new prostaglandin F2 alpha analog, on aqueous humor dynamics in human eyes. Ophthalmology 100:1297-304
Hayashi, M; Yablonski, M E; Boxrud, C et al. (1989) Decreased formation of aqueous humour in insulin-dependent diabetic patients. Br J Ophthalmol 73:621-3

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