Effect of Glucose on Ocular Blood Flow

Sponsor

University Hospital, Basel, Switzerland (Other)

Overall Status

Completed

CT.gov ID

NCT00350129

Collaborator

(none)

Enrollment

Location

Duration (Months)

11.8

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The primary objective is to assess the effect of glucose on retinal vascular diameter in otherwise healthy vasospastic subjects compared to non-vasospastic controls.

The secondary objective is to compare the effect of glucose also on choroidal blood flow in otherwise healthy vasospastic subjects with non-vasospastic controls.

Condition or Disease	Intervention/Treatment	Phase
Coronary Vasospasm

Detailed Description

It is known that a glucose load can induce an increase in ocular blood flow. Acute hyperglycemia increases retinal vessel diameters in animals and humans. The purpose of this study is to compare the effect of glucose on the ocular blood flow in vasospastics and nonvasospastics. Body core temperature depends on basal metabolism. Peripheral vasoconstriction is a physiological way to preserve core temperature of the body. The etiology of primary vasospastic syndrome is unknown and potentially represents simply a reaction to a defective metabolism. Based on this hypothesis, vasospastics are expected to show a different vascular reaction to glucose.

On both study days, after an overnight fast, the subjects will be seated for 30 minutes in the Lab and local tropicamide will be applied for pupil dilatation. After stabilisation of blood pressure Retinal vessel diameter and choroidal blood flow will be assessed. Baseline blood glucose levels will be measured. Afterwards study substance (75 gram of Glucose or Aspartate) will be applied in 3 dl of water. One and a half hour later, the vascular measurements will be repeated. Ath the end of hemodynamic assessments, blood sugar level will be measured again.

Study Design

Study Type:

Observational

Actual Enrollment :

24 participants

Observational Model:

Case-Control

Time Perspective:

Prospective

Official Title:

Influence of Plasma Glucose Levels on Retinal Vascular Diameter and Choroidal Blood Flow in Vasospastic Subjects

Study Start Date :

Dec 1, 2002

Actual Primary Completion Date :

Feb 1, 2003

Actual Study Completion Date :

Feb 1, 2003

Arms and Interventions

Arm	Intervention/Treatment
1 healthy vasospastic subjects
2 healthy non-vasospastic subjects

Outcome Measures

Primary Outcome Measures

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 85 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

No history of the following problems: ocular or systemic disease; chronic or current systemic or topical medication; or of drug or alcohol abuse
normal blood pressure (100-140 / 60-90 mmhg)
best corrected visual acuity above 20/25 in both eyes
no pathological findings upon a slit-lamp examination and indirect fundoscopy
ametropia within -3 to +3 diopters of spherical equivalent
less than 1 diopter astigmatism
IOP < 20 mmHg in both eyes
Subjects will be classified as vasospastic if they relate a clear history of frequent cold hands (answering yes to the questions: "do you have always cold hands, even during summer time?" and "do other people tell you that you have cold hands?") and as normals if they deny such a history
Vasospastic propensity will also be assessed by capillaroscopy