Blood Flow Regulation in Glaucoma

Study Overview
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Brief Summary
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Glaucoma is one of the leading causes for blindness in industrialized countries. It is characterized by a progressive loss of retinal ganglion cells, morphological changes in the optic nerve head and a characteristic loss of visual field. Although increased intraocular pressure has been identified as the major risk factor for the development and the progression of the disease it has been speculated for a long time that impaired ocular blood flow may contribute to the pathogenesis of the disease. This concept has been supported by several epidemiological studies showing that low ocular perfusion pressure and small retinal vessel caliber are associated with the disease. The proposed study tests the hypothesis that patients with glaucoma have reduced total retinal blood flow as compared to healthy subjects. Additionally, autoregulation of blood flow will be investigated during an increase in ocular perfusion pressure. This is of importance because it may clarify the degree of vascular involvement in glaucoma.

Conditions
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Glaucoma

Intervention / Treatment
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* Other: Isometric exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with open angle glaucoma: - Diagnosis of manifest open angle glaucoma as defined as pathological optic disc appearance, glaucoma hemifield test outside normal limits and/or untreated intraocular pressure ≥ 21 mmHg on at least three measurements in the medical history. Mean deviation in the visual field test < 10 decibel Healthy control subjects: normal ophthalmic findings and intraocular pressure < 20 mmHg on at least three measurements no evidence of increased intraocular pressure in the medical history no signs of glaucomatous damage in the optic disc or the glaucoma hemifield test Exclusion Criteria: Presence or history of a severe medical condition as judged by the investigator Abuse of alcoholic beverages Participation in a clinical trial in the 3 weeks preceding the study Exfoliation glaucoma Pigmentary glaucoma Secondary glaucoma Ocular hypertension History of acute angle closure Intraocular surgery within the last 6 months History of epilepsia Diabetes mellitus Ocular inflammation or infection within the last 3 months Untreated hypertension with systolic blood pressure >160 mmHg, diastolic blood pressure >95 mmHg Pregnancy or lactating

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Glaucoma Patients<br>Patients with primary open angle glaucoma | Other: Isometric exercise<br> <br> |
| Healthy controls<br>age- and sex matched controls | Other: Isometric exercise<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Optic nerve head blood flow |  | once | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal blood flow |  | once |