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Estrogen-replacement therapy: effects on retrobulbar hemodynamics.
M Harris-Yitzhak1, A Harris, Z Ben-Refael
1Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5133, USA.
American Journal of Ophthalmology
|June 14, 2000
Summary
Estrogen replacement therapy reduces vascular resistance in the ophthalmic artery for postmenopausal women. However, it does not significantly impact blood flow in posterior ciliary arteries, suggesting aging affects these vessels.
Area of Science:
- Ophthalmology
- Endocrinology
- Vascular Biology
Background:
- Estrogen replacement therapy (ERT) is known to promote vasodilation and enhance blood flow in peripheral arteries.
- The specific effects of estrogen on retrobulbar arterial perfusion remain less understood.
Purpose of the Study:
- To investigate the influence of estrogen on blood flow within the major and minor retrobulbar arteries.
- To determine if estrogen replacement therapy (ERT) affects ocular perfusion in postmenopausal women.
Main Methods:
- A comparative study involving postmenopausal women on ERT (n=16), age-matched controls not on ERT (n=16), and young women (n=20).
- Color Doppler imaging was utilized to analyze flow velocities in the ophthalmic, central retinal, and posterior ciliary arteries.
Main Results:
- Postmenopausal women on ERT demonstrated reduced resistance indexes in the ophthalmic artery, comparable to young women.
- Flow velocities in the central retinal artery showed no significant differences across the three groups.
- Young women exhibited higher peak systolic and end-diastolic velocities in posterior ciliary arteries compared to both postmenopausal groups.
Conclusions:
- ERT appears to lower vascular resistance distal to the ophthalmic artery in postmenopausal women, mimicking levels seen in younger individuals.
- Estrogen replacement therapy has minimal effect on blood flow velocities within the posterior ciliary arteries.
- Aging may independently decrease perfusion in posterior ciliary arteries, potentially increasing the risk for eye diseases like glaucoma and age-related macular degeneration.