The pathophysiology of glaucoma, one of the most common causes of visual impairment, is not clearly understood. Several recent reports have suggested that abnormalities of the circulation of the optic nerve head may increase the susceptibility to glaucomatous damage. The main goal of this grant is to investigate whether optic nerve head circulatory abnormalities are present in patients with primary open- angle glaucoma (POAG), normal-tension glaucoma (NTG) and ocular hypertension (OHT). To achieve this goal we will use laser Doppler flowmetry, a non-invasive technique that provides relative measurements of blood velocity, blood volume and blood flow, to study optic nerve head hemodynamics. This grant has three specific aims which will test the following hypotheses: 1) Baseline optic nerve head blood flow in patients with POAG, NTG and OHT is different from normal. In POAG patients with asymmetric disease between eyes and no visual field in the fellow eye, abnormal blood flow is present in the eye with normal visual field. 2) Vascular autoregulatory responses to acute increases in IOP in these patients are different from normal. 3) Abnormalities of baseline optic nerve head blood flow and its autoregulation in POAG patients with asymmetric visual field defects between superior and inferior hemifield correlate with areas of glaucomatous damage. The results obtained from these studies will help us assess whether optic nerve head circulatory abnormalities are associated with the development of glaucomatous pathology. If hemodynamic abnormalities are present, then attention can be focused on altering the optic nerve circulation as a means of treating glaucoma.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
1R01EY011479-01A2
Application #
2465529
Study Section
Visual Sciences C Study Section (VISC)
Project Start
1997-12-01
Project End
2001-11-30
Budget Start
1997-12-01
Budget End
1998-11-30
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Lam, Andrew; Piltz-Seymour, Jody; Dupont, Joan et al. (2005) Laser Doppler flowmetry in asymmetric glaucoma. Curr Eye Res 30:221-7
Zink, J M; Grunwald, J E; Piltz-Seymour, J et al. (2003) Association between lower optic nerve laser Doppler blood volume measurements and glaucomatous visual field progression. Br J Ophthalmol 87:1487-91
Piltz-seymour, J R; Grunwald, J E; Hariprasad, S M et al. (2001) Optic nerve blood flow is diminished in eyes of primary open-angle glaucoma suspects. Am J Ophthalmol 132:63-9
Piltz-Seymour, J R (1999) Laser Doppler flowmetry of the optic nerve head in glaucoma. Surv Ophthalmol 43 Suppl 1:S191-8
Grunwald, J E; Piltz, J; Hariprasad, S M et al. (1999) Optic nerve blood flow in glaucoma: effect of systemic hypertension. Am J Ophthalmol 127:516-22
Grunwald, J E; Iannaccone, A; DuPont, J (1999) Effect of isosorbide mononitrate on the human optic nerve and choroidal circulations. Br J Ophthalmol 83:162-7
Schocket, L S; Grunwald, J E; Tsang, A F et al. (1999) The effect of pregnancy on retinal hemodynamics in diabetic versus nondiabetic mothers. Am J Ophthalmol 128:477-84
Grunwald, J E; Piltz, J; Hariprasad, S M et al. (1998) Optic nerve and choroidal circulation in glaucoma. Invest Ophthalmol Vis Sci 39:2329-36