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Study Title and Description

The effect of caffeine on retrobulbar hemodynamics.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title The effect of caffeine on retrobulbar hemodynamics.
Author B Ozkan,N Yüksel,Y Anik,O Altintas,A Demirci,Y Cağlar,
Country
Year 2008
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? To investigate the acute effect of caffeine on intraocular pressure and retrobulbar blood flow velocity.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) This study was planned as a randomized, double masked, placebo-controlled trial in order to determine the effect of caffeine on retrobulbar blood flow in healthy volunteers. All subjects underwent a complete ophthalmic examination consisting of best corrected visual acuity, slit lamp biomicroscopy, and dilated fundoscopy. Intraocular pressure was measured by Goldmann applanation tonometry. Brachial artery systemic blood pressure was also assessed by automated sphygmomanometry (Tycos Wall Sphygmomanometer, Welch Allyn, Skaneateles Falls, NY, USA). Baseline intraocular pressure, systolic and diastolic blood pressure, and color Doppler imaging values were measured. After these procedures, subjects received 300 mg of oral caffeine or placebo. All measurements were repeated 1 hr after administration of caffeine or placebo tablets. Ultrasonographic evaluation was performed within 1 week of the clinical examination by an experienced radiologist (Y.A.) who was masked to the medication given to the patients. To minimize errors induced from physiologic variations in blood flow, velocity measurements were averaged from three pulse waveforms. Color Doppler USG imaging (Toshiba Eccocee) was performed using a 7.5-MHz linear transducer. All examinations were carried out while the subjects were in the supine position with their eyes closed. The examination technique of color Doppler USG imaging was the same as that of a general ocular color Doppler imaging examination, with the transducer being used with acoustic gel. In the first instance, a color Doppler image of the optic nerve was obtained, which provides the most useful landmark for the identification of the retrobulbar vessels. Resistive index was calculated as peak systolic velocity minus end diastolic velocity, divided by peak systolic velocity
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Intraoccular pressure
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List additional health endpoints (separately). 2 Systemic blood pressure (diastolic and systolic)
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List additional health endpoints (separately).3 Retrobulbar blood flow velocities and resistive index in the ophthalmic, central retinal, nasal short posterior ciliary, and temporal short posterior ciliary arteries.
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Intraocular pressure was measured by Goldmann applanation tonometry. Brachial artery systemic blood pressure was also assessed by automated sphygmomanometry (Tycos Wall Sphygmomanometer, Welch Allyn, Skaneateles Falls, NY, USA). Color Doppler USG imaging (Toshiba Eccocee) was performed using a 7.5-MHz linear transducer.
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) A separate or control (placebo) group was used compared to a group exposed to caffeine.
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) xclusion criteria were (1) presence of any ocular disease; (2) presence of systemic diseases such as hypertension, diabetes, or vascular disease; (3) daily caffeine consumption of three or more cups of coffee; (4) use of any systemic drugs and alcohol abuse.
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What conflicts of interest were reported? The authors stated that they had no conflicts of interest.
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Refid 18798083
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What were the sources of funding? No sources of funding were mentioned.
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Results & Comparisons

No Results found.