Document Detail

Evaluation of the Zeiss retinal vessel analyser.
MedLine Citation:
PMID:  11049956     Owner:  NLM     Status:  MEDLINE    
AIM: To investigate the reproducibility and sensitivity of the Zeiss retinal vessel analyser, a new method for the online determination of retinal vessel diameters in healthy subjects. METHODS: Two model drugs were administered, a peripheral vasoconstrictor (the alpha receptor agonist phenylephrine) and a peripheral vasodilator (the nitric oxide donor sodium nitroprusside) in stepwise increasing doses. Nine healthy young subjects were studied in a placebo controlled double masked three way crossover design. Subjects received intravenous infusions of either placebo or stepwise increasing doses of phenylephrine (0.5, 1, or 2 microg/kg/min) or sodium nitroprusside (0.5, 1, or 2 microg/kg/min). Retinal vessel diameters were measured with the new Zeiss retinal vessel analyser. Retinal leucocyte velocity, flow, and density were measured with the blue field entoptic technique. The reproducibility of measurements was assessed with coefficients of variation and intraclass correlation coefficients. RESULTS: Placebo and phenylephrine did not influence retinal haemodynamics, although the alpha receptor antagonist significantly increased blood pressure. Sodium nitroprusside induced a significant increase in retinal venous and arterial diameters (p<0.001 each), leucocyte density (p=0.001), and leucocyte flow (p=0.024) despite lowering blood pressure to a significant degree. For venous and arterial vessel size measurements short term coefficients of variation were 1.3% and 2.6% and intraclass correlation coefficients were 0.98 and 0.96, respectively. The sensitivity was between 3% and 5% for retinal veins and 5% and 7% for retinal arteries. CONCLUSIONS: These data indicate that the Zeiss retinal vessel analyser is an accurate system for the assessment of retinal diameters in healthy subjects. In addition, nitric oxide appears to have a strong influence on retinal vascular tone.
K Polak; G Dorner; B Kiss; E Polska; O Findl; G Rainer; H G Eichler; L Schmetterer
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  The British journal of ophthalmology     Volume:  84     ISSN:  0007-1161     ISO Abbreviation:  Br J Ophthalmol     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2000-12-05     Completed Date:  2000-12-05     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0421041     Medline TA:  Br J Ophthalmol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1285-90     Citation Subset:  IM    
Department of Clinical Pharmacology, University of Vienna, Vienna, Austria.
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MeSH Terms
Adrenergic alpha-Agonists / administration & dosage
Cross-Over Studies
Nitroprusside / administration & dosage
Ophthalmology / instrumentation*
Phenylephrine / administration & dosage
Regional Blood Flow / drug effects,  physiology
Reproducibility of Results
Retinal Vessels / anatomy & histology,  drug effects,  physiology*
Vasodilator Agents / administration & dosage
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Placebos; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 59-42-7/Phenylephrine

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