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Anterior optic nerve capillary blood flow response to diurnal variation of mean ocular perfusion pressure in early untreated primary open-angle glaucoma.
Invest Ophthalmol Vis Sci 2005; 46(12):4581-7IO

Abstract

PURPOSE

To examine the impact of diurnal variation in intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) on the variation in anterior optic nerve capillary blood flow (BF) in patients with untreated early primary open-angle glaucoma (uPOAG) and healthy volunteers.

METHODS

Fourteen patients with uPOAG (age, 56.3 +/- 12 years [SD]; seven men) and 14 normal subjects (age, 57.6 +/- 9.9 years; five men) were examined. Diurnal IOP, systolic (SBP) and diastolic (DBP) blood pressures, and optic nerve head (ONH) topography were measured every hour; and diurnal BF was measured by flowmeter every 2 hours between 0700 and 2200 hours. A perfusion image analyzer was used to calculate the mean BF within the rim (mean rim flow, MRF). The local flow (LF) was calculated using the median and mean flow rates within a 10 x 10-pixel window placed on the rim in the area of maximum topography fluctuation (MTF). The MOPP was then calculated. Mixed-effect linear models were used to analyze the repeated measures data in which both fixed and random effects were included.

RESULTS

IOP, BP, and MOPP had significant diurnal variation (P < 0.040). LF measured at the sector of MTF significantly changed in patients with uPOAG (P = 0.006) but not in normal subjects (P = 0.660). MRF did not show significant diurnal change in either group (P = 0.130, P = 0.770). LF increased significantly after lunch in the uPOAG group (P = 0.001). SBP had a significant effect on LF over the course of the day in the uPOAG group (P = 0.043). The diurnal change in IOP, BP, and MOPP did not have a significant effect on MTF in either group. In uPOAG, the local flow, in areas of greatest topographical change, correlated inversely with IOP at 0700 hours (P < or = 0.002).

CONCLUSIONS

The mean rim flow did not change during the day, implying that the anterior optic nerve capillary blood flow was autoregulated in both normal subjects and in patients with uPOAG, despite significant changes in IOP and MOPP. However, the regions of greatest diurnal change in rim topography (MTF) had significant diurnal change in capillary blood flow in patients with uPOAG but not in normal subjects.

Authors+Show Affiliations

School of Optometry, University of Waterloo, Waterloo, Canada. msehi@med.miami.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16303952

Citation

Sehi, Mitra, et al. "Anterior Optic Nerve Capillary Blood Flow Response to Diurnal Variation of Mean Ocular Perfusion Pressure in Early Untreated Primary Open-angle Glaucoma." Investigative Ophthalmology & Visual Science, vol. 46, no. 12, 2005, pp. 4581-7.
Sehi M, Flanagan JG, Zeng L, et al. Anterior optic nerve capillary blood flow response to diurnal variation of mean ocular perfusion pressure in early untreated primary open-angle glaucoma. Invest Ophthalmol Vis Sci. 2005;46(12):4581-7.
Sehi, M., Flanagan, J. G., Zeng, L., Cook, R. J., & Trope, G. E. (2005). Anterior optic nerve capillary blood flow response to diurnal variation of mean ocular perfusion pressure in early untreated primary open-angle glaucoma. Investigative Ophthalmology & Visual Science, 46(12), pp. 4581-7.
Sehi M, et al. Anterior Optic Nerve Capillary Blood Flow Response to Diurnal Variation of Mean Ocular Perfusion Pressure in Early Untreated Primary Open-angle Glaucoma. Invest Ophthalmol Vis Sci. 2005;46(12):4581-7. PubMed PMID: 16303952.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Anterior optic nerve capillary blood flow response to diurnal variation of mean ocular perfusion pressure in early untreated primary open-angle glaucoma. AU - Sehi,Mitra, AU - Flanagan,John G, AU - Zeng,Leilei, AU - Cook,Richard J, AU - Trope,Graham E, PY - 2005/11/24/pubmed PY - 2006/1/13/medline PY - 2005/11/24/entrez SP - 4581 EP - 7 JF - Investigative ophthalmology & visual science JO - Invest. Ophthalmol. Vis. Sci. VL - 46 IS - 12 N2 - PURPOSE: To examine the impact of diurnal variation in intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) on the variation in anterior optic nerve capillary blood flow (BF) in patients with untreated early primary open-angle glaucoma (uPOAG) and healthy volunteers. METHODS: Fourteen patients with uPOAG (age, 56.3 +/- 12 years [SD]; seven men) and 14 normal subjects (age, 57.6 +/- 9.9 years; five men) were examined. Diurnal IOP, systolic (SBP) and diastolic (DBP) blood pressures, and optic nerve head (ONH) topography were measured every hour; and diurnal BF was measured by flowmeter every 2 hours between 0700 and 2200 hours. A perfusion image analyzer was used to calculate the mean BF within the rim (mean rim flow, MRF). The local flow (LF) was calculated using the median and mean flow rates within a 10 x 10-pixel window placed on the rim in the area of maximum topography fluctuation (MTF). The MOPP was then calculated. Mixed-effect linear models were used to analyze the repeated measures data in which both fixed and random effects were included. RESULTS: IOP, BP, and MOPP had significant diurnal variation (P < 0.040). LF measured at the sector of MTF significantly changed in patients with uPOAG (P = 0.006) but not in normal subjects (P = 0.660). MRF did not show significant diurnal change in either group (P = 0.130, P = 0.770). LF increased significantly after lunch in the uPOAG group (P = 0.001). SBP had a significant effect on LF over the course of the day in the uPOAG group (P = 0.043). The diurnal change in IOP, BP, and MOPP did not have a significant effect on MTF in either group. In uPOAG, the local flow, in areas of greatest topographical change, correlated inversely with IOP at 0700 hours (P < or = 0.002). CONCLUSIONS: The mean rim flow did not change during the day, implying that the anterior optic nerve capillary blood flow was autoregulated in both normal subjects and in patients with uPOAG, despite significant changes in IOP and MOPP. However, the regions of greatest diurnal change in rim topography (MTF) had significant diurnal change in capillary blood flow in patients with uPOAG but not in normal subjects. SN - 0146-0404 UR - https://www.unboundmedicine.com/medline/citation/16303952/Anterior_optic_nerve_capillary_blood_flow_response_to_diurnal_variation_of_mean_ocular_perfusion_pressure_in_early_untreated_primary_open_angle_glaucoma_ L2 - http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.05-0209 DB - PRIME DP - Unbound Medicine ER -