title: Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature.
abstract: OBJECTIVE
  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 (r=0.23, P<0.05).
  
  
  CONCLUSIONS
  This was the first study to determine the sampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.
authors.affiliation: Palmer Trinity School (L.W.), Miami, FL; Bascom Palmer Eye Institute (J.Y., H.J., H.R.C.-C., V.L.P., D.C.D., W.J.F., J.W.), Department of Ophthalmology, University of Miami, Miami, FL; Zhongshan Ophthalmic Centre (J.Y.), Sun Yat-sen University, Department of Ophthalmology and Optometry, Guangzhou, China; School of Ophthalmology and Optometry (W.Y.), Wenzhou Medical College, Wenzhou, China; Departments of Neurology (H.J.), and Microbiology and Immunology (H.R.C.-C., V.L.P.), University of Miami, FL; and Statistic Division (W.J.F.), Bascom Palmer Eye Institute, University of Miami, Miami, FL.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Jin
authors.initials: J
authors.lastname: Yuan
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Wentao
authors.initials: W
authors.lastname: Yan
authors.forename: Hector R
authors.initials: HR
authors.lastname: Cintrón-Colón
authors.forename: Victor L
authors.initials: VL
authors.lastname: Perez
authors.forename: Delia C
authors.initials: DC
authors.lastname: DeBuc
authors.forename: William J
authors.initials: WJ
authors.lastname: Feuer
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D003228:Conjunctiva / Q000098:blood supply*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D055806:Microvessels / Q000033:anatomy & histology*; D066167:Slit Lamp
references.citation: Clin Hemorheol Microcirc. 2010;46(1):69-73
references.pmid: 20852364
references.citation: Endocr Pract. 2001 Sep-Oct;7(5):358-63
references.pmid: 11585371
references.citation: Clin Hemorheol Microcirc. 2009;42(4):285-95
references.pmid: 19628894
references.citation: Microvasc Res. 2010 Mar;79(2):109-13
references.pmid: 20053367
references.citation: Diabetes. 2007 Nov;56(11):2790-6
references.pmid: 17686944
references.citation: Clin Ophthalmol. 2013;7:1197-1204
references.pmid: 23814457
references.citation: Transplantation. 1999 Oct 15;68(7):927-32
references.pmid: 10532529
references.citation: Clin Hemorheol Microcirc. 2009;41(4):229-39
references.pmid: 19318716
references.citation: Microvasc Res. 2014 Mar;92:62-71
references.pmid: 24444784
references.citation: J Pediatr Hematol Oncol. 2012 Apr;34(3):169-74
references.pmid: 22278200
references.citation: Biorheology. 2007;44(5-6):375-86
references.pmid: 18401076
references.citation: Blood. 2001 Jun 1;97(11):3401-4
references.pmid: 11369629
references.citation: Clin Hemorheol Microcirc. 2012;51(1):77-86
references.pmid: 22240372
references.citation: Am J Hematol. 2013 Aug;88(8):661-4
references.pmid: 23657867
references.citation: Am J Hematol. 2010 Nov;85(11):899-901
references.pmid: 20872552
references.citation: Microvasc Res. 2010 Sep;80(2):202-8
references.pmid: 20478318
references.citation: Microvasc Res. 2013 Jan;85:34-9
references.pmid: 23154279