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Asiedu K, Krishnan AV, Kwai N, Poynten A, Markoulli M. Conjunctival microcirculation in ocular and systemic microvascular disease. Clin Exp Optom 2023; 106:694-702. [PMID: 36641840 DOI: 10.1080/08164622.2022.2151872] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 01/16/2023] Open
Abstract
The conjunctival microcirculation is an accessible complex network of micro vessels whose quantitative assessment can reveal microvascular haemodynamic properties. Currently, algorithms for the measurement of conjunctival haemodynamics use either manual or semi-automated systems, which may provide insight into overall conjunctival health, as well as in ocular and systemic disease. These algorithms include functional slit-lamp biomicroscopy, laser doppler flowmetry, optical coherence tomography angiography, orthogonal polarized spectral imaging, computer-assisted intravitral microscopy, diffuse reflectance spectroscopy and corneal confocal microscopy. Furthermore, several studies have demonstrated a relationship between conjunctival microcirculatory haemodynamics and many diseases such as dry eye disease, Alzheimer's disease, diabetes, hypertension, sepsis, coronary microvascular disease, and sickle cell anaemia. This review aims to describe conjunctival microcirculation, its characteristics, and techniques for its measurement, as well as the association between conjunctival microcirculation and microvascular abnormalities in disease states.
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Affiliation(s)
- Kofi Asiedu
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Arun V Krishnan
- School of Clinical Medicine, University of New South Wales, Sydney, Australia
- Department of Neurology, Prince of Wales Hospital, Sydney, Australia
| | - Natalie Kwai
- School of Medical Sciences, University of sydney, Sydney, Australia
| | - Ann Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, Australia
| | - Maria Markoulli
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Deep learning and computer vision techniques for microcirculation analysis: A review. PATTERNS (NEW YORK, N.Y.) 2022; 4:100641. [PMID: 36699745 PMCID: PMC9868679 DOI: 10.1016/j.patter.2022.100641] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The analysis of microcirculation images has the potential to reveal early signs of life-threatening diseases such as sepsis. Quantifying the capillary density and the capillary distribution in microcirculation images can be used as a biological marker to assist critically ill patients. The quantification of these biological markers is labor intensive, time consuming, and subject to interobserver variability. Several computer vision techniques with varying performance can be used to automate the analysis of these microcirculation images in light of the stated challenges. In this paper, we present a survey of over 50 research papers and present the most relevant and promising computer vision algorithms to automate the analysis of microcirculation images. Furthermore, we present a survey of the methods currently used by other researchers to automate the analysis of microcirculation images. This survey is of high clinical relevance because it acts as a guidebook of techniques for other researchers to develop their microcirculation analysis systems and algorithms.
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Kvernebo AK, Miyamoto T, Drolsum L, Moe MC, Måsøy SE, Sunagawa G, Dessoffy R, Karimov JH, Fukamachi K, Kvernebo K. Ocular surface microcirculation is better preserved with pulsatile versus continuous flow during cardiopulmonary bypass-An experimental pilot. Artif Organs 2021; 46:786-793. [PMID: 34866193 DOI: 10.1111/aor.14137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/29/2021] [Accepted: 11/29/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND Non-pulsatile cardiopulmonary bypass (CPB) may induce microvascular dysregulation. In piglets, we compared ocular surface microcirculation during pulsatile versus continuous flow (CF) bypass. METHODS Ocular surface microcirculation in small tissue volumes (~0.1 mm3 ) at limbus (high metabolic rate) and bulbar conjunctiva (low metabolic rate) was examined in a porcine model using computer assisted video microscopy and diffuse reflectance spectroscopy, before and after 3 and 6 h of pulsatile (n = 5 piglets) or CF (n = 3 piglets) CPB. Functional capillary density, capillary flow velocity and microvascular oxygen saturation were quantified. RESULTS At limbus, velocities improved with pulsatility (p < 0.01) and deteriorated with CF (p < 0.01). In bulbar conjunctiva, velocities were severely reduced with CF (p < 0.01), accompanied by an increase in capillary density (p < 0.01). Microvascular oxygen saturation decreased in both groups. CONCLUSION Ocular surface capillary densities and flow patterns are better preserved with pulsatile versus CF during 6 h of CPB in sleeping piglets.
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Affiliation(s)
- Anne Kari Kvernebo
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,The Circulation Laboratory, Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway
| | - Takuma Miyamoto
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Liv Drolsum
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Morten Carstens Moe
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | | | - Gengo Sunagawa
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Raymond Dessoffy
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Jamshid H Karimov
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Kiyotaka Fukamachi
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Knut Kvernebo
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,The Circulation Laboratory, Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway.,ODI Medical AS, Oslo, Norway
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