title: Measurement variability of the bulbar conjunctival microvasculature in healthy subjects using functional slit lamp biomicroscopy (FSLB).
abstract: The goal was to determine the variability of the quantitative measurement of the bulbar conjunctival microvascular morphology and hemodynamics by testing the repeatability and variation during office hours. Functional slit-lamp biomicroscopy (FSLB) was used to image the bulbar conjunctival microvasculature, including the vessel diameter, blood flow velocity/rate and fractal dimensions of the microvascular network. The temporal side of the bulbar conjunctiva in 20 healthy subjects was imaged. The subject was imaged at 9 AM to test the measurement repeatability by two independent graders. The intraclass correlation coefficient (ICC) and coefficient of repeatability (CoR) were calculated. These same subjects were then imaged every two hours from 9 AM to 5 PM to test the variation during office hours. Custom software was used to semi-automatically process all measurements. The CoR% and ICC values between two graders for measuring the vessel diameter were 4.87% and 0.989, respectively. For the axial blood flow velocity, the CoR% and ICC were 11.49% and 0.997, respectively. From 9 AM to 5 PM, there were no significant variations in the vessel diameter and hemodynamics (P>0.05), whereas the fractal dimensions of the non-invasive microvascular perfusion maps (nMPMs) were significantly increased at 3 PM and 5 PM compared with the baseline obtained at 9 AM (P<0.05). FSLB appears to be capable of measuring vessel diameter, blood flow velocity and fractal dimension of the microvascular network in the bulbar conjunctiva. Slight variations over office hours were observed in the microvascular network, while the blood flow velocity remained stable.
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Department of Neurology, University of Miami, Miami, FL, USA. Electronic address: h.jiang@med.miami.edu.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Aizhu
authors.initials: A
authors.lastname: Tao
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Department of Ophthalmology, Red-Cross Hospital, Hangzhou, Zhejiang, China.
authors.forename: Shuangqing
authors.initials: S
authors.lastname: Wu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Yan
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA.
authors.forename: Che
authors.initials: C
authors.lastname: Liu
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA.
authors.forename: Delia Cabrera
authors.initials: DC
authors.lastname: DeBuc
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D003228:Conjunctiva / Q000098:blood supply*; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D055806:Microvessels; D008875:Middle Aged; D015203:Reproducibility of Results; D066167:Slit Lamp; D012984:Software; D013997:Time Factors
keywords: Bulbar conjunctival microvascular morphology; Diurnal variation during office hours; Functional slit lamp biomicroscopy (FSLB); Hemodynamics; Repeatability