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Shats D, Balasubramanian T, Sidelnikov D, Das U, Onyekaba NA, Forbes HE, Lu N, Williams K, Levin MR, Sundararajan S, Vij S, Gadagkar H, Rege A, Saeedi O, Chen V, Alexander JL. Association of Speckle-Based Blood Flow Measurements and Fluorescein Angiography in Infants with Retinopathy of Prematurity. OPHTHALMOLOGY SCIENCE 2024; 4:100463. [PMID: 38591050 PMCID: PMC11000102 DOI: 10.1016/j.xops.2023.100463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 11/01/2023] [Accepted: 12/26/2023] [Indexed: 04/10/2024]
Abstract
Purpose To determine the correlation between blood flow metrics measured by intravenous fluorescein angiography (IVFA) and the blood flow velocity index (BFVi) obtained by laser speckle contrast imaging (LSCI) in infants with retinopathy of prematurity (ROP). Design Prospective comparative pilot study. Subjects Seven eyes from 7 subjects with ROP. Methods Unilateral LSCI and IVFA data were obtained from each subject in the neonatal intensive care unit. Five LSCI-based metrics and 5 IVFA-based metrics were extracted from images to quantify blood flow patterns in the same region of interest. Correlation between LSCI-based and IVFA-based blood flow metrics was compared between 2 subgroups of ROP severity: moderate ROP (defined as stage ≤ 2 without Plus disease) and severe ROP (defined as stage ≥3 or Plus disease). Main Outcome Measures Pearson and Kendall rank correlation coefficients between IVFA and LSCI metrics; Student t test P values comparing LSCI metrics between "severe" and "moderate" ROP groups. Results Pearson correlations between IVFA and LSCI included arterial-venous transit time (AVTT) and peak BFVi (pBFVi; r = -0.917; P = 0.004), AVTT and dip BFVi (dBFVi; r = -0.920; P = 0.003), AVTT and mean BFVi (r = -0.927- P = 0.003), and AVTT and volumetric rise index (r = -0.779; P = 0.039). Kendall rank correlation between AVTT and dBFVi was r = -0.619 (P = 0.051). pBFVi was higher in severe ROP than in moderate ROP (8.4 ± 0.6 and 4.4 ± 1.8, respectively; P = 0.0045 using the 2-sample t test with pooled variance and P = 0.0952 using the Wilcoxon rank-sum test). Conclusions Correlation was found between blood flow metrics obtained by IVFA and noninvasive LSCI techniques. We demonstrate the feasibility of obtaining quantitative metrics using LSCI in infants with ROP in this pilot study; however, further investigation is needed to evaluate its potential use in clinical assessment of ROP severity. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Daniel Shats
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Tara Balasubramanian
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Danielle Sidelnikov
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Urjita Das
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ndidi-Amaka Onyekaba
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - He E. Forbes
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Noela Lu
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kristin Williams
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Moran R. Levin
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Sripriya Sundararajan
- Department of Neonatology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Shitiz Vij
- Vasoptic Medical, Inc., Columbia, Maryland
| | | | | | - Osamah Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Victoria Chen
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Janet L. Alexander
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland
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Cho E, Das U, Sidelnikov D, Balasubramanian T, Shats D, Mansoor S, Forbes HE, Zhou J, Kapoor R, Chase S, Kore M, Williams K, Saeedi O, Sundararajan S, Levin MR, Magder L, Alexander JL. Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity. Sci Rep 2024; 14:12790. [PMID: 38834830 PMCID: PMC11150459 DOI: 10.1038/s41598-024-63534-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 05/29/2024] [Indexed: 06/06/2024] Open
Abstract
This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA) and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP). 38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27 and 47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r = - 0.2 and r = - 0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.
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Affiliation(s)
- Euna Cho
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Urjita Das
- University of Maryland School of Medicine, Baltimore, MD, USA
| | | | | | - Daniel Shats
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shaiza Mansoor
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - He Eun Forbes
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jason Zhou
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ria Kapoor
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sera Chase
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Madi Kore
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristin Williams
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Osamah Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sripriya Sundararajan
- Division of Neonatology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Moran Roni Levin
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Laurence Magder
- Department of Biostatistics and Epidemiology, University of Maryland, Baltimore, MD, USA
| | - Janet Leath Alexander
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
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Cho E, Das U, Sidelnikov D, Balasubramanian T, Shats D, Mansoor S, Forbes HE, Zhou J, Kapoor R, Chase S, Kore M, Williams K, Saeedi O, Sundararajan S, Levin MR, Magder L, Alexander J. Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity. RESEARCH SQUARE 2024:rs.3.rs-3909449. [PMID: 38464120 PMCID: PMC10925429 DOI: 10.21203/rs.3.rs-3909449/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA), and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP).38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27-47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r=-0.2 and r=-0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.
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Affiliation(s)
- Euna Cho
- University of Maryland School of Medicine
| | - Urjita Das
- University of Maryland School of Medicine
| | | | | | | | | | | | - Jason Zhou
- University of Maryland School of Medicine
| | - Ria Kapoor
- University of Maryland School of Medicine
| | - Sera Chase
- University of Maryland School of Medicine
| | - Madi Kore
- University of Maryland School of Medicine
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Hassanpoor N, Abdolrahimi V, Niyousha MR. Central Retinal Vein Occlusion with Three-Retinal Quadrant Involvement: Another Focus on Optic Disc Head Vascular Anatomy Variations. Case Rep Ophthalmol Med 2023; 2023:6648367. [PMID: 37941565 PMCID: PMC10630022 DOI: 10.1155/2023/6648367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/06/2023] [Accepted: 10/09/2023] [Indexed: 11/10/2023] Open
Abstract
A 50-year-old male patient with sudden visual acuity loss in his right eye came to our clinic. Visual acuity at presentation was 1/10 in right eye and 10/10 in left. The patient was otherwise healthy Caucasian man without any history of previous systemic or ophthalmic disease. There was not any history of amblyopia and refractive error. Anterior segment findings were unremarkable. Three quadrants of retina were fully involved with central retinal vein occlusion (CRVO) features including retinal hemorrhages, retinal edema obscuring retinal details, and cotton wool spots while sparing inferior temporal quadrant. Inferior temporal quadrant sparing in this patient is due to a specific retinal vascular anatomical variation. In conclusion, in unusual presentations of retinal vascular branch obstructions, considering retinal vascular anatomy variations would help us to explain the clinical presentation more precisely in some cases.
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Affiliation(s)
- Narges Hassanpoor
- Retina & Vitreous Service, Nikookari Eye Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vahid Abdolrahimi
- Retina & Vitreous Service, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohamad Reza Niyousha
- Retina & Vitreous Service, Nikookari Eye Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
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Arthur E, Ravichandran S, Snyder PJ, Alber J, Strenger J, Bittner AK, Khankan R, Adams SL, Putnam NM, Lypka KR, Piantino JA, Sinoff S. Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer's disease. Alzheimers Res Ther 2023; 15:172. [PMID: 37828548 PMCID: PMC10568786 DOI: 10.1186/s13195-023-01312-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Compared to standard neuro-diagnostic techniques, retinal biomarkers provide a probable low-cost and non-invasive alternative for early Alzheimer's disease (AD) risk screening. We have previously quantified the periarteriole and perivenule capillary free zones (mid-peripheral CFZs) in cognitively unimpaired (CU) young and older adults as novel metrics of retinal tissue oxygenation. There is a breakdown of the inner retinal blood barrier, pericyte loss, and capillary non-perfusion or dropout in AD leading to potential enlargement of the mid-peripheral CFZs. We hypothesized the mid-peripheral CFZs will be enlarged in CU older adults at high risk for AD compared to low-risk individuals. METHODS 20 × 20° optical coherence tomography angiography images consisting of 512 b-scans, 512 A-scans per b-scan, 12-µm spacing between b-scans, and 5 frames averaged per each b-scan location of the central fovea and of paired major arterioles and venules with their surrounding capillaries inferior to the fovea of 57 eyes of 37 CU low-risk (mean age: 66 years) and 50 eyes of 38 CU high-risk older adults (mean age: 64 years; p = 0.24) were involved in this study. High-risk participants were defined as having at least one APOE e4 allele and a positive first-degree family history of AD while low-risk participants had neither of the two criteria. All participants had Montreal Cognitive Assessment scores ≥ 26. The mid-peripheral CFZs were computed in MATLAB and compared between the two groups. RESULTS The periarteriole CFZ of the high-risk group (75.8 ± 9.19 µm) was significantly larger than that of the low-risk group (71.3 ± 7.07 µm), p = 0.005, Cohen's d = 0.55. The perivenule CFZ of the high-risk group (60.4 ± 8.55 µm) was also significantly larger than that of the low-risk group (57.3 ± 6.40 µm), p = 0.034, Cohen's d = 0.42. There were no significant differences in foveal avascular zone (FAZ) size, FAZ effective diameter, and vessel density between the two groups, all p > 0.05. CONCLUSIONS Our results show larger mid-peripheral CFZs in CU older adults at high risk for AD, with the potential for the periarteriole CFZ to serve as a novel retinal vascular biomarker for early AD risk detection.
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Affiliation(s)
- Edmund Arthur
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Swetha Ravichandran
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peter J Snyder
- Department of Neurology, Alpert Medical School of Brown University, Providence, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Jessica Alber
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Butler Hospital Memory & Aging Program, Providence, RI, USA
| | - Jennifer Strenger
- Butler Hospital Memory & Aging Program, Providence, RI, USA
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI, USA
| | - Ava K Bittner
- Department of Ophthalmology, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Rima Khankan
- Southern California College of Optometry, Marshall B. Ketchum University, Fullerton, CA, USA
| | | | - Nicole M Putnam
- State University of New York College of Optometry, New York, NY, USA
| | - Karin R Lypka
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Juan A Piantino
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
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6
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Vinnett A, Kandukuri J, Le C, Cho KA, Sinha A, Asanad S, Thompson G, Chen V, Rege A, Saeedi OJ. Dynamic Alterations in Blood Flow in Glaucoma Measured with Laser Speckle Contrast Imaging. Ophthalmol Glaucoma 2022; 5:250-261. [PMID: 34673279 PMCID: PMC9013729 DOI: 10.1016/j.ogla.2021.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE To assess the repeatability of blood flow velocity index (BFVi) metrics obtained with a recently Food and Drug Administration-cleared laser speckle contrast imaging device, the XyCAM RI (Vasoptic Medical, Inc), and to characterize differences in these metrics among control, glaucoma suspect, and glaucoma participants. DESIGN Prospective, observational study. PARTICIPANTS Forty-six participants: 20 control, 16 glaucoma suspect, and 10 glaucoma participants, 1 eye per participant. METHODS Key dynamic BFVi metrics-mean, peak, dip, volumetric rise index (VRI), volumetric fall index (VFI), time to rise (TtR), time to fall (TtF), blow-out time (BOT), skew, and acceleration time index-were measured in the optic disc, optic disc vessels, optic disc perfusion region, and macula in 4 imaging sessions on the same day. Intrasession and intersession variability were calculated using the coefficient of variation (CV) for each metric in each region of interest (ROI). Values for each dynamic BFVi variable were compared between glaucoma, glaucoma suspect, and control participants using bivariate and multivariate analysis. Pearson correlation coefficients were used to correlate each variable in each ROI with age, intraocular pressure, cup-to-disc ratio (CDR), mean deviation, pattern standard deviation, retinal nerve fiber layer thickness, and minimum rim width. MAIN OUTCOME MEASURES Coefficient of variation for the intrasession and intersession variability for each dynamic BFVi metric in each ROI and differences in each metric in each ROI between each diagnostic group. RESULTS Intersession CV for mean, peak, dip, VRI, VFI, TtR, and TtF ranged from 3.2 ± 2.5% to 11.0 ± 3.8%. Age, CDR, OCT metrics, and visual field metrics showed significant correlations with dynamic BFVi variables. Peak, mean, dip, VRI, and VFI were significantly lower in patients with glaucoma than in control participants in all ROIs except the fovea. These metrics also were significantly lower in glaucoma patients than glaucoma suspect patients in the disc vessels. CONCLUSIONS Dynamic blood flow metrics measured with the XyCAM RI are reliable, are associated with structural and functional glaucoma metrics, and are significantly different among glaucoma, glaucoma suspect, and control participants. The XyCAM RI may serve as an important tool in glaucoma management in the future.
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Affiliation(s)
- Alfred Vinnett
- Department of Ophthalmology and Visual Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | | | - Christopher Le
- Department of Ophthalmology and Visual Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | | | | | - Samuel Asanad
- Department of Ophthalmology and Visual Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | - Ginger Thompson
- Department of Ophthalmology/Hamilton Eye Institute, University of Tennessee Health Sciences Center, Memphis, Tennessee
| | - Victoria Chen
- Department of Ophthalmology and Visual Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | | | - Osamah J Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland Baltimore, Baltimore, Maryland.
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7
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Puyo L, Spahr H, Pfäffle C, Hüttmann G, Hillmann D. Retinal blood flow imaging with combined full-field swept-source optical coherence tomography and laser Doppler holography. OPTICS LETTERS 2022; 47:1198-1201. [PMID: 35230326 DOI: 10.1364/ol.449739] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Full-field swept-source optical coherence tomography (FF-SS-OCT) and laser Doppler holography (LDH) are two holographic imaging techniques presenting unique capabilities for ophthalmology. We report on interlaced FF-SS-OCT and LDH imaging with a single instrument. Effectively, retinal blood flow and pulsation could be quasi-simultaneously monitored. This instrument holds potential for a wide scope of ophthalmic applications.
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Marino MJ, Gehlbach PL, Rege A, Jiramongkolchai K. Current and novel multi-imaging modalities to assess retinal oxygenation and blood flow. Eye (Lond) 2021; 35:2962-2972. [PMID: 34117399 PMCID: PMC8526664 DOI: 10.1038/s41433-021-01570-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/28/2021] [Accepted: 04/20/2021] [Indexed: 02/05/2023] Open
Abstract
Retinal ischemia characterizes the underlying pathology in a multitude of retinal diseases that can ultimately lead to vision loss. A variety of novel imaging modalities have been developed to characterize retinal ischemia by measuring retinal oxygenation and blood flow in-vivo. These technologies offer valuable insight into the earliest pathophysiologic changes within the retina and provide physicians and researchers with new diagnostic and monitoring capabilities. Future retinal imaging technologies with the capability to provide affordable, noninvasive, and comprehensive data on oxygen saturation, vasculature, and blood flow mechanics are needed. This review will highlight current and future trends in multimodal imaging to assess retinal blood flow and oxygenation.
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Affiliation(s)
- Michael J. Marino
- grid.415233.20000 0004 0444 3298Department of Medicine, MedStar Union Memorial Hospital, Baltimore, MD USA
| | - Peter L. Gehlbach
- grid.21107.350000 0001 2171 9311Retina Division, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Abhishek Rege
- grid.505446.6Vasoptic Medical, Inc., Baltimore, MD USA
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9
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Patel DD, Dhalla AH, Viehland C, Connor TB, Lipinski DM. Development of a Preclinical Laser Speckle Contrast Imaging Instrument for Assessing Systemic and Retinal Vascular Function in Small Rodents. Transl Vis Sci Technol 2021; 10:19. [PMID: 34403474 PMCID: PMC8374978 DOI: 10.1167/tvst.10.9.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To develop and test a non-contact, contrast-free, retinal laser speckle contrast imaging (LSCI) instrument for use in small rodents to assess vascular anatomy, quantify hemodynamics, and measure physiological changes in response to retinal vascular dysfunction over a wide field of view (FOV). Methods A custom LSCI instrument capable of wide-field and non-contact imaging in small rodents was constructed. The effect of camera gain, laser power, and exposure duration on speckle contrast variance was standardized before the repeatability of LSCI measurements was determined in vivo. Finally, the ability of LSCI to detect alterations in local and systemic vascular function was evaluated using a laser-induced branch retinal vein occlusion and isoflurane anesthesia model, respectively. Results The LSCI system generates contrast-free maps of retinal blood flow with a 50° FOV at >376 frames per second (fps) and under a short exposure duration (>50 µs) with high reliability (intraclass correlation R = 0.946). LSCI was utilized to characterize retinal vascular anatomy affected by laser injury and longitudinally measure alterations in perfusion and blood flow profile. Under varied doses of isoflurane, LSCI could assess cardiac and systemic vascular function, including heart rate, peripheral resistance, contractility, and pulse propagation. Conclusions We present a LSCI system for detecting anatomical and physiological changes in retinal and systemic vascular health and function in small rodents. Translational Relevance Detecting and quantifying early anatomical and physiological changes in vascular function in animal models of retinal, systemic, and neurodegenerative diseases could strengthen our understanding of disease progression and enable the identification of new prognostic and diagnostic biomarkers for disease management and for assessing treatment efficacies.
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Affiliation(s)
- Dwani D Patel
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Ophthalmology and Visual Science, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Al-Hafeez Dhalla
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Thomas B Connor
- Department of Ophthalmology and Visual Science, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Daniel M Lipinski
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Ophthalmology and Visual Science, Medical College of Wisconsin, Milwaukee, WI, USA.,Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
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10
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Arthur E, Alber J, Thompson LI, Sinoff S, Snyder PJ. OCTA reveals remodeling of the peripheral capillary free zones in normal aging. Sci Rep 2021; 11:15593. [PMID: 34341456 PMCID: PMC8329222 DOI: 10.1038/s41598-021-95230-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
The retinal neurovascular unit consists of blood vessel endothelial cells, pericytes, neurons, astrocytes, and Müller cells that form the inner retinal blood barrier. A peripheral capillary free zone (pCFZ) represents the distance that oxygen and nutrients must diffuse to reach the neural retina, and serves as a metric of retinal tissue oxygenation. The pCFZs are formed based on oxygen saturation in the retinal arterioles and venules. Because retinal arterioles contain a larger concentration of oxygenated blood than venules, there is a reduced need for capillaries to exist closely to arterioles compared to venules. Therefore, in a healthy individual, larger periarteriole CFZs are expected compared to perivenule CFZs. With normal aging, there is atrophy of the inner retinal neurons, and consequently reduced extraction of oxygen and nutrients from the retinal vessels (i.e., increased oxygen saturation). Therefore, we hypothesized that the peripheral CFZ will remodel with normal aging. Using Optical Coherence Tomography Angiography, we showed that the pCFZs do remodel in normal aging with large (perivenule: η2p = 0.56) and moderate (periarteriole: η2p = 0.12) effect sizes, opening the possibility that such changes may be further increased by neurodegenerative diseases that adversely impact the health of the retinal neural cell layers.
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Affiliation(s)
- Edmund Arthur
- grid.20431.340000 0004 0416 2242Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI USA ,grid.20431.340000 0004 0416 2242George and Anne Ryan Institute for Neuroscience, University of Rhode Island, 130 Flagg Road, Kingston, RI 02881 USA ,grid.273271.20000 0000 8593 9332Butler Hospital Memory and Aging Program, Providence, RI USA
| | - Jessica Alber
- grid.20431.340000 0004 0416 2242Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI USA ,grid.20431.340000 0004 0416 2242George and Anne Ryan Institute for Neuroscience, University of Rhode Island, 130 Flagg Road, Kingston, RI 02881 USA ,grid.273271.20000 0000 8593 9332Butler Hospital Memory and Aging Program, Providence, RI USA
| | - Louisa I. Thompson
- grid.273271.20000 0000 8593 9332Butler Hospital Memory and Aging Program, Providence, RI USA ,grid.40263.330000 0004 1936 9094Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, RI USA
| | - Stuart Sinoff
- grid.432466.10000 0004 0382 745XBayCare Health, Clearwater, FL USA
| | - Peter J. Snyder
- grid.20431.340000 0004 0416 2242Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI USA ,grid.20431.340000 0004 0416 2242George and Anne Ryan Institute for Neuroscience, University of Rhode Island, 130 Flagg Road, Kingston, RI 02881 USA
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11
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DeBuc DC, Rege A, Smiddy WE. Use of XyCAM RI for Noninvasive Visualization and Analysis of Retinal Blood Flow Dynamics During Clinical Investigations. Expert Rev Med Devices 2021; 18:225-237. [PMID: 33635742 DOI: 10.1080/17434440.2021.1892486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Ocular blood flow plays a critical role in eye health by nourishing the retinal and ocular tissues with oxygen and nutrients and removal of ocular metabolic waste. Imaging of retinal and optic blood flow may provide insights for early and more specific diagnoses of ocular vascular disorder and facilitate eye-based biomarkers applicable to neurological health assessment and research. AREAS COVERED The ability of the XyCAM RI (Vasoptic Medical Inc., MD, USA) to visualize and to analyze ocular blood flow dynamics XyCAM RI using laser speckle contrast imaging is reviewed and compared with concurrent clinical ophthalmic imaging technologies like optical coherence tomography - angiography (OCT-A), fundus imaging, fluorescein angiography (FA), indocyanine green angiography (ICGA), laser Doppler flowmetry (LDF), and laser speckle flowgraphy (LSFG). EXPERT OPINION XyCAM RI, with its unprecedented imaging capabilities to assess blood flow dynamics provides a powerful tool to ophthalmic researchers and doctors to obtain greater clinical insights into the physiological status of the posterior segment and treatment approaches for various diseases in a very patient-friendly, noninvasive manner, unlike dye-based angiographic techniques such as FA or ICG. XyCAM RI is well suited as a modality that could close the gap between current screening and comprehensive eye exams.
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Affiliation(s)
- Delia Cabrera DeBuc
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - William E Smiddy
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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