Vessel Sampling and Blood Flow Velocity Distribution with Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature

Liang Wang, Jin Yuan, Hong Jiang, Wentao Yan, Hector R. Cintrón-Colón, Victor L Perez Quinones, Delia Cabrera DeBuc, William J Feuer, Jianhua Wang

Research output: Contribution to journalArticle

10 Scopus citations


Purpose: This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. Methods: Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. Results: The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r0.23, P

Original languageEnglish (US)
Pages (from-to)135-140
Number of pages6
JournalEye and Contact Lens
Issue number2
StatePublished - Mar 1 2016



  • Bulbar conjunctiva
  • Distribution histogram
  • Functional slitlamp biomicroscopy
  • Hemodynamics
  • Microvasculature
  • Morphology
  • Sample size

ASJC Scopus subject areas

  • Ophthalmology

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