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Miraftabi A, Yavari A, Banifatemi M, Nilforushan N, Zand A, Chaibakhsh S. OCT angiographic evaluation of changes in macula and optic nerve head vessel density after a water drinking test in glaucomatous and healthy eyes. Int Ophthalmol 2024; 44:320. [PMID: 38977648 DOI: 10.1007/s10792-024-03237-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/22/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE To evaluate the effects of a water drinking test (WDT) on the intraocular pressure (IOP) and vascular density of the optic nerve head and macula in healthy individuals and those with primary open glaucoma using optical coherence tomography angiography. METHODS In this prospective comparative study, 30 healthy patients and 44 POAG subjects were divided into two groups. The study's outcome measures were the IOP and vessel density of the optic nerve and macular area. After ingesting 1000 ml of water in 5 min, the effect of the WDT on the IOP and the vascular density of the macular area and optic nerve head were measured at baseline and then 20, 40, and 60 min later at intervals of 20 min. RESULTS The initial IOP in the healthy and glaucomatous eye groups was comparable (15.94 ± 2.6 and 16.87 ± 4.21 mmHg, respectively, P = 0.506). The IOP of both groups peaked at 40' measurements. POAG eyes had significantly higher IOP elevation (4.34 ± 0.30 vs. 2.24 ± 0.30 mmHg, P < 0.001). The glaucomatous eyes had lower radial peripapillary capillary (RPC) and whole macular superficial capillary plexus (SCP) densities at baseline (48.55 ± 5.99 vs. 51.33 ± 3.75) and (48.92 ± 3.41 vs. 45.29 ± 5.29), respectively (P < 0.001). After the WDT, the change in vessel density between groups in the RPC, whole superficial, and deep capillary plexuses was insignificant (SCP and DCP of 0.66 and 0.70, respectively, P = 0.16). CONCLUSION The WDT caused a significant IOP jump in both glaucomatous and healthy eyes, but generally, the alterations in the glaucomatous eyes were more pronounced. The changes in vascular density in the macula and optic nerve head were similar between the groups.
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Affiliation(s)
- Arezoo Miraftabi
- Eye Research Center, The Five Senses Health Institute, Rassoul Akram Hospital, School of Medicine, Iran University of Medical Sciences, Sattarkhan Avenue-Niayesh St, Tehran, Iran.
| | - Azadeh Yavari
- Eye Research Center, The Five Senses Health Institute, Rassoul Akram Hospital, School of Medicine, Iran University of Medical Sciences, Sattarkhan Avenue-Niayesh St, Tehran, Iran
| | - Mohammad Banifatemi
- Eye Research Center, The Five Senses Health Institute, Rassoul Akram Hospital, School of Medicine, Iran University of Medical Sciences, Sattarkhan Avenue-Niayesh St, Tehran, Iran
| | - Naveed Nilforushan
- Eye Research Center, The Five Senses Health Institute, Rassoul Akram Hospital, School of Medicine, Iran University of Medical Sciences, Sattarkhan Avenue-Niayesh St, Tehran, Iran
| | - Amin Zand
- Eye Research Center, The Five Senses Health Institute, Rassoul Akram Hospital, School of Medicine, Iran University of Medical Sciences, Sattarkhan Avenue-Niayesh St, Tehran, Iran
| | - Samira Chaibakhsh
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
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Alswailmi FK. A Cross Talk between the Endocannabinoid System and Different Systems Involved in the Pathogenesis of Hypertensive Retinopathy. Pharmaceuticals (Basel) 2023; 16:ph16030345. [PMID: 36986445 PMCID: PMC10058254 DOI: 10.3390/ph16030345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/26/2023] Open
Abstract
The prognosis of hypertension leads to organ damage by causing nephropathy, stroke, retinopathy, and cardiomegaly. Retinopathy and blood pressure have been extensively discussed in relation to catecholamines of the autonomic nervous system (ANS) and angiotensin II of the renin–angiotensin aldosterone system (RAAS) but very little research has been conducted on the role of the ECS in the regulation of retinopathy and blood pressure. The endocannabinoid system (ECS) is a unique system in the body that can be considered as a master regulator of body functions. It encompasses the endogenous production of its cannabinoids, its degrading enzymes, and functional receptors which innervate and perform various functions in different organs of the body. Hypertensive retinopathy pathologies arise normally due to oxidative stress, ischemia, endothelium dysfunction, inflammation, and an activated renin–angiotensin system (RAS) and catecholamine which are vasoconstrictors in their biological nature. The question arises of which system or agent counterbalances the vasoconstrictors effect of noradrenaline and angiotensin II (Ang II) in normal individuals? In this review article, we discuss the role of the ECS and its contribution to the pathogenesis of hypertensive retinopathy. This review article will also examine the involvement of the RAS and the ANS in the pathogenesis of hypertensive retinopathy and the crosstalk between these three systems in hypertensive retinopathy. This review will also explain that the ECS, which is a vasodilator in its action, either independently counteracts the effect produced with the vasoconstriction of the ANS and Ang II or blocks some of the common pathways shared by the ECS, ANS, and Ang II in the regulation of eye functions and blood pressure. This article concludes that persistent control of blood pressure and normal functions of the eye are maintained either by decreasing systemic catecholamine, ang II, or by upregulation of the ECS which results in the regression of retinopathy induced by hypertension.
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Affiliation(s)
- Farhan Khashim Alswailmi
- Department of Pharmacy Practice, College of Pharmacy, University of Hafr Al Batin, Hafr Al Batin 39524, Saudi Arabia
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3
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Effect of Mydriatic Administration On Retinal Hemodynamics in Glaucoma: An Optical Coherence Tomography Angiography Study. J Glaucoma 2022; 31:659-665. [PMID: 35439783 DOI: 10.1097/ijg.0000000000002039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 04/02/2022] [Indexed: 11/26/2022]
Abstract
PRCIS Pupillary dilation with 0.5% tropicamide and 2.5% phenylephrine resulted in a statistically significant decrease in foveal avascular zone (FAZ) metrics in glaucoma eyes. This observation emphasizes the critical role of pupillary status in interpreting glaucomatous vascular alterations detected by OCTA. PURPOSE To evaluate the influence of mydriatic eye drops on optical coherence tomography angiography (OCTA) parameters in patients with primary open-angle glaucoma (POAG). METHODS A total of 20 POAG eyes and 20 control eyes were recruited in the study. The imaging area on the fundus was visualized by AngioPlex (Cirrus 5000 HD-OCT; Carl Zeiss Meditec) using en face view of 3×3▒mm and 6×6▒mm preview scans. Images were generated before and after the instillation of topical 0.5% tropicamide and 2.5% phenylephrine. Optic nerve head (ONH) perfusion, ONH flux index, macular perfusion density, macular vessel density, and foveal avascular zone (FAZ) measurements were consecutively obtained for each session. Differences between the pre-and post-dilation measurements were evaluated in POAG patients and controls. RESULTS POAG eyes showed a statistically significant decrease in the FAZ area from a mean of 0.29▒mm2to 0.25▒mm2(P=0.037) and FAZ perimeter from a mean of 2.27▒mm to 2.09▒mm (P=0.045) in the OCTA 6×6▒mm scan area after tropicamide/phenylephrine instillation. Pre-and post-dilation measurements of ONH perfusion and ONH flux index were significantly lower in the glaucoma group compared to controls (P<0.05, for all). CONCLUSION Topical pupillary dilation with 0.5% tropicamide and 2.5% phenylephrine results in a statistically significant reduction in the FAZ area and FAZ perimeter in POAG eyes. Further OCTA studies are needed for the diagnostic value of vascular changes due to pupil dilation in glaucoma.
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Gameiro GR, Gameiro GR, Farah ME, Wang J, Schor P. Retinal microvascular density modifications during the water drinking test. Eur J Ophthalmol 2021; 32:1602-1609. [PMID: 34137302 DOI: 10.1177/11206721211024058] [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] [Indexed: 11/16/2022]
Abstract
PURPOSE The water drinking test (WDT) is a well-known stress test that increases intraocular pressure (IOP) momentarily and can indicate risk of glaucoma progression. This study focuses on correlating changes in the retinal microvascular plexus with the WDT in young healthy subjects. METHODS A total of 20 eyes of 20 healthy young subjects (mean age 24.37 ± 2.17 years) were included in this study. In our protocol, WDT consisted of drinking 1 L of water within 5 min. Outcome measures in this prospective observational study were mean arterial pressure (MAP), heart rate (HR), IOP, and retinal vessel density of both superficial and deep macular retina using optical coherence tomography angiography (OCTA), which were assessed before water ingestion and four times after at 15-min intervals. OCTA images were later quantified by fractal analysis (box counting [Dbox]). One-way repeated measures analysis of variance (ANOVA) was used to assess the effects of WDT on each of the parameters. RESULTS The WDT resulted in significant peak changes of the following parameters compared to baseline: IOP: 15.63 ± 3.37 versus 18.38 ± 4.53 mmHg at 30 min, p < 0.001; HR: 75.74 ± 12.23 versus 64.95 ± 11.37 bpm at 15 min, p < 0.001; deep retinal vessel density 1.758 ± 0.14 versus 1.749 ± 0.16 at 15 min, p = 0.040. CONCLUSIONS Besides IOP elevation and systemic effects in HR, WDT is associated with temporary modifications of the deep vascular plexus in young healthy subjects.
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Affiliation(s)
- Gustavo Rosa Gameiro
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of Sao Paulo - EPM/UNIFESP, São Paulo, São Paulo, Brazil
| | - Giovana Rosa Gameiro
- Health Sciences Center, State University of Londrina, Londrina, Parana, Brazil.,Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Michel Eid Farah
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of Sao Paulo - EPM/UNIFESP, São Paulo, São Paulo, Brazil
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Paulo Schor
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of Sao Paulo - EPM/UNIFESP, São Paulo, São Paulo, Brazil
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Kannenkeril D, Frost S, Nolde JM, Kiuchi MG, Carnagarin R, Lugo-Gavidia LM, Chan J, Joyson A, Matthews VB, Herat LY, Azzam O, Mehdizadeh M, Vignarajan J, Kanagasingam Y, Schlaich MP. Microvascular changes at different stages of chronic kidney disease. J Clin Hypertens (Greenwich) 2020; 23:309-316. [PMID: 33340251 PMCID: PMC8029790 DOI: 10.1111/jch.14138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 12/26/2022]
Abstract
Patients with progressing chronic kidney disease (CKD) are more likely to experience cardio‐ and cerebrovascular events than progressing to end‐stage renal disease. The authors explored whether retinal microvascular calibers differed with the degree of renal impairment and between the standard and extended optic disk and may serve as a simple additional tool for risk stratification in this highly vulnerable patient cohort. The authors analyzed central retinal arteriolar and venular equivalent calibers (CRAE, CRVE) at different retinal zones (zone B&C) using digital retinal imaging in hypertensive patients with stage 2 (n = 66) or stage 3 CKD (n = 30). Results were adjusted for age, sex, HbA1c, and 24‐hour diastolic blood pressure. Mean eGFR was 77.7 ± 8.9 and 48.8 ± 7.9 ml/min/1.73 m2 for stage 2 and 3 CKD, respectively. CRAE and CRVE in zones B and C were significantly lower in patients with stage 3 CKD compared to patients with stage 2 CKD (CRAE‐B:141.1 ± 21.4 vs. 130.5 ± 18.9 µm, p = .030; CRAE‐C:137.4 ± 19.4 vs 129.2 ± 18.2 µm, p = .049; CRVE‐B:220.8 ± 33.0 vs. 206.0 ± 28.4 µm, p = .004; and CRVE‐C:215.9 ± 33.0 vs. 201.2 ± 25.1µm, p = .003). In patients with stage 2 CKD, CRAE‐B was higher than CRAE‐C (141.1 ± 21.4 vs. 137.4 ± 19.4µm, p < .001). In contrast, such a difference was not found in patients with stage 3 CKD. CRAE of both retinal zones correlated with eGFR for the entire cohort. In patients with stage 3 CKD, retinal narrowing is more pronounced compared to patients with stage 2 CKD. Whether the novel observation of difference in arteriolar caliber between zones B and C in stage 2 CKD could serve as an early marker of CKD progression warrants further investigation.
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Affiliation(s)
- Dennis Kannenkeril
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia.,Department of Nephrology and Hypertension, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Shaun Frost
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, WA, Australia.,Australian e-Health Research Centre, Perth, WA, Australia
| | - Janis M Nolde
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Márcio Galindo Kiuchi
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Revathy Carnagarin
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Leslie Marisol Lugo-Gavidia
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Justine Chan
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia.,Departments of Cardiology and Nephrology, Royal Perth Hospital, Perth, WA, Australia
| | - Anu Joyson
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia.,Departments of Cardiology and Nephrology, Royal Perth Hospital, Perth, WA, Australia
| | - Vance B Matthews
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Lakshini Y Herat
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Omar Azzam
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia
| | - Maryam Mehdizadeh
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, WA, Australia.,Australian e-Health Research Centre, Perth, WA, Australia
| | - Janardhan Vignarajan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, WA, Australia.,Australian e-Health Research Centre, Perth, WA, Australia
| | - Yogesan Kanagasingam
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, WA, Australia.,Australian e-Health Research Centre, Perth, WA, Australia
| | - Markus P Schlaich
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Perth, WA, Australia.,Departments of Cardiology and Nephrology, Royal Perth Hospital, Perth, WA, Australia.,Neurovascular Hypertension & Kidney Disease Laboratory, Baker Heart and Diabetes Institute, Melbourne, Vic., Australia
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Wentzel A, Malan L, von Känel R, Smith W, Malan NT. Heart rate variability, the dynamic nature of the retinal microvasculature and cardiac stress: providing insight into the brain-retina-heart link: the SABPA study. Eye (Lond) 2020; 34:835-846. [PMID: 31278382 PMCID: PMC7182573 DOI: 10.1038/s41433-019-0515-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/15/2019] [Accepted: 06/14/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND AIMS Decreased heart-rate-variability (HRV) indicates increased sympathetic nervous system (SNS) activity and modulation with a shift in the sympatho-vagal balance towards SNS predominance. Increased SNS activity may precede volume-loading hypertension, contribute to increases in cardiac troponin T (cTnT), endothelial dysfunction and small vessel disease. Therefore, we investigated the retinal vasculature, HRV during flicker-light-induced-provocation (FLIP) and systemic cTnT, a marker of cardiac stress, to provide further evidence in support of the brain-retina-heart link. METHODS Cross-sectional observations were obtained from a bi-ethnic cohort (N = 264), aged 23-68 years. Fasting serum samples for cTnT were obtained. Retinal vascular calibres were quantified from mydriatic eye fundus images and dynamic retinal vessel calibre responses were determined during FLIP. Time-and frequency domain parameters of HRV were calculated during FLIP for each participant. RESULTS Africans had wider venules and attenuated time domain parameters during FLIP. In Africans, inverse associations emerged between arteriolar dilation and both cTnT and root-mean squared of the standard deviations of successive RR-intervals (rMSSD) (p = 0.030), and between arteriolar constriction and both low-frequency expressed in normalised units (LFnu) (p = 0.003) and high-frequency expressed in normalised units (p = 0.021). Wider venules inversely associated with standard deviation of the NN intervals (SDNN) as well as LFnu (p = 0.009) in Africans. An opposite profile was observed in Caucasians with both time-and frequency domain parameters of HRV in relation to retinal vessel structure and function. CONCLUSION FLIP elicited increased SNS activity and modulation in this bi-ethnic cohort. In Africans, decreased HRV during FLIP accompanied arteriolar and venular responses and elevated systemic levels of cTnT, implying that the SNS exerted a significant effect on the smooth muscle tone of the retinal vasculature. Disrupted retinal autoregulation may imply general autonomic nervous system dysfunction; exemplifying central control by the brain on all systemic regulatory functions, across different vascular beds.
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Affiliation(s)
- Annemarie Wentzel
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa
| | - Leoné Malan
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
| | - Roland von Känel
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa
- Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Wayne Smith
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa
- South African Medical Research Council, Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa
| | - Nicolaas T Malan
- Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa
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Chen W, Chen Z, Xiang Y, Deng C, Zhang H, Wang J. Simultaneous influence of sympathetic autonomic stress on Schlemm's canal, intraocular pressure and ocular circulation. Sci Rep 2019; 9:20060. [PMID: 31882796 PMCID: PMC6934569 DOI: 10.1038/s41598-019-56562-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 12/12/2019] [Indexed: 11/09/2022] Open
Abstract
This study aimed to investigate changes in Schlemm's canal, intraocular pressure and ocular blood circulation following the activation of the sympathetic nervous system. Twenty healthy volunteers were enrolled in this study. The cold pressor test (CPT) was adopted. Cross-sectional area of Schlemm's canal (SCAR), superficial and deep retinal vessel densities (s-RVD;d-RVD), pupil diameter (PD), intraocular pressure (IOP), mean ocular perfusion pressure (MOPP) and heart rate variability (HRV) were measured at three time-points: baseline (T0) and 5 min (T1) and 10 min (T2) after the CPT. After cold stimulation, LF/HF index (the ratio of low frenquency and high frenquency) increased significantly. IOP decreased from 16.9 ± 1.9 mmHg at baseline to 16.4 ± 2.7 mmHg at T1 and to 15.2 ± 2.7 mmHg at T2. The nasal cross-sectional area of SCAR (SCAR-n) increased from 6283.9 ± 2696.2 µm2 at baseline to 8392.9 ± 3258.7 µm2 at T1 and to 10422.0 ± 3643.8 µm2 at T2. The temporal cross-sectional area of SCAR (SCAR-t) increased from 6414.5 ± 2218.7 µm2 at baseline to 8610.8 ± 2317.1 µm2 at T1 and to 11544.0 ± 4129.2 µm2 at T2. The expansion of Schlemm's canal was observed after the CPT might be caused by sympathetic nerve stimulation, subsequently leading to decreased IOP.
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Affiliation(s)
- Wei Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiqi Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Xiang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohua Deng
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junming Wang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Association of dietary nitrate intake with retinal microvascular structure in older adults. Eur J Nutr 2019; 59:2057-2063. [PMID: 31309281 DOI: 10.1007/s00394-019-02055-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 07/09/2019] [Indexed: 01/17/2023]
Abstract
PURPOSE Existing research suggests that changes to retinal vascular caliber reflect nitric oxide (NO)-dependent endothelial dysfunction. Dietary nitrate is an important source of NO; however, studies on the link between dietary nitrate intake and retinal microvasculature are lacking. We aimed to assess the cross-sectional association between intake of dietary nitrate (from vegetable and non-vegetable sources) and retinal arteriolar and venular caliber among older adults. METHODS Participants from the Blue Mountains Eye Study aged 49+ years with complete data at baseline on diet and retinal vessel measures were analyzed (n = 2813). Dietary intake was assessed using a validated semi-quantitative food-frequency questionnaire. Nitrate intake from vegetable and non-vegetable sources was estimated using a validated comprehensive database and other published data where necessary. Fundus photographs were taken and retinal vascular caliber measured using validated computer-assisted techniques and summarized. RESULTS Participants in the lowest versus highest tertile of vegetable nitrate intake had significantly narrower retinal arterioles: 186.2 ± 0.48 versus 187.6 ± 0.48 µm (multivariable-adjusted p = 0.04). After multivariable adjustment, each 10-unit higher intake of total nitrate and vegetable nitrate was associated with 0.089 ± 0.004 and 0.090 ± 0.004 µm wider retinal arteriolar caliber, respectively, both p = 0.03. Each 10-unit higher vegetable nitrate intake was associated with 0.092 ± 0.005 µm narrower retinal venules (p = 0.05). CONCLUSION Intake of dietary nitrate, particularly from vegetable sources, was associated with beneficial variations in both retinal arteriolar and venular caliber among older adults. Further research into associations between dietary nitrate and the retinal microvasculature could allow for greater understanding and possible prevention of clinical cardiovascular events.
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Frost S, Gregory C, Robinson L, Yu S, Xiao D, Mehdizadeh M, Burnham S, Dehghani C, Vignarajan J, Kanagasingam Y, Schlaich MP, Prentice D. Effect of Pupil Dilation with Tropicamide on Retinal Vascular Caliber. Ophthalmic Epidemiol 2019; 26:400-407. [PMID: 31267797 DOI: 10.1080/09286586.2019.1639198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Purpose: The retinal blood vessels reflect changes in the brain's micro-circulation and these changes have been shown to correlate with the incidence of diseases such as stroke, heart disease and Alzheimer's disease. Studies investigating the retinal vasculature routinely use pupil dilation with tropicamide to optimize image acquisition and quality. The aim of this study was to investigate the effects of tropicamide on retinal vascular parameters using retinal photography.Methods: The study was performed on 41 healthy young subjects of both sexes, using tropicamide to dilate only the right pupil, leaving the left as a control.Results: Pupil dilation with tropicamide resulted in reduced retinal vessel width measures based on standardized approaches, particularly reduced arteriolar caliber (p < .0005). However, closer investigation of the images revealed reduced fundus image magnification in the post-tropicamide images, based on reduced optic nerve head diameter (p < .0005) and longitudinal analysis with image registration and affine transformation (p < .0001). No change in vessel width parameters was observed after adjustment for image magnification.Conclusion: These results suggest that tropicamide does not change the width of the retinal vessels, however width parameters as measured by standard approaches may be reduced due to image magnification changes resulting from cycloplegia. In this study, improved optic nerve head segmentation for image scale conversion removed the magnification error. With this correction, the tropicamide intervention had no effect on vessel width parameters in young healthy people and could be utilized in future without affecting the results of retinal vascular analysis.
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Affiliation(s)
- Shaun Frost
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Cynthia Gregory
- Dobney Hypertension Centre, Royal Perth Hospital, Perth, Australia.,University of Western Australia, Perth, Australia
| | - Liam Robinson
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Shuang Yu
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Di Xiao
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Maryam Mehdizadeh
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Samantha Burnham
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Cirous Dehghani
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia
| | - Janardhan Vignarajan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Yogesan Kanagasingam
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, Australia.,Australian e-Health Research Centre, Perth, Australia
| | - Markus P Schlaich
- Dobney Hypertension Centre, Royal Perth Hospital, Perth, Australia.,University of Western Australia, Perth, Australia
| | - David Prentice
- Perron Institute for Neurological and Translational Science, Perth, Australia
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10
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Ulusoy MO, Kal A, Işik-Ulusoy S, Kal Ö. Choroidal thickness in patients with fibromyalgia and correlation with disease severity. Indian J Ophthalmol 2018; 66:428-432. [PMID: 29480257 PMCID: PMC5859601 DOI: 10.4103/ijo.ijo_877_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose: To evaluate and compare choroidal thickness in patients with fibromyalgia (FM) and healthy controls. Methods: In this prospective, cross-sectional study, forty eyes of 40 patients with FM and 40 eyes of 40 age- and sex-matched healthy subjects were enrolled. FM was diagnosed according to the American College of Rheumatology criteria. The choroidal thickness measurements of the subjects were obtained using spectral-domain optical coherence tomography (RTVue-100, Optovue). Widespread pain index (WPI), symptom severity scale (SSS), and fibromyalgia impact questionnaire (FIQ) scores were recorded. The choroidal thickness measurements of the groups were compared, and correlations among the WPI, SSS, and FIQ scores and these measurements were calculated. Results: Choroidal thicknesses at 1500 μm nasally were 198.5 ± 46.7 μm and 306.3 ± 85.4 μm; at 1000 μm nasally were 211.7 ± 50.2 μm and 310.05 ± 87.26 μm; at 500 μm nasally were 216 ± 55.05 μm and 311.5 ± 83.4 μm; at subfoveal region were 230.9 ± 58.4 μm and 332.4 ± 91.3 μm; at 500 μm temporally 227.5 ± 58.1 μm and 318.15 ± 92.3 μm; at 1000 μm temporally 224.5 ± 57.07 μm and 315.1 ± 84.2 μm; at 1500 μm temporally 212.5 ± 56.08 μm and 312.9 ± 87.8 μm in the FM and control groups, respectively (P < 0.001). Choroidal thicknesses were thinner at all measurement location, except temporal 1000 and 1500 in patients with FIQ score ≥50 than in FIQ score <50. Conclusion: The results of this study demonstrated that choroidal thickness decreases in patients with FM and correlated with disease activity. This choroidal changes might be related with the alterations in autonomic nervous system functioning. Further studies are needed to evaluate the etiopathologic relationship between choroidal thickness and FM.
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Affiliation(s)
- Mahmut Oguz Ulusoy
- Department of Ophthalmology, School of Medicine, Baskent University, Konya Research Hospital, Konya, Turkey
| | - Ali Kal
- Department of Ophthalmology, School of Medicine, Baskent University, Konya Research Hospital, Konya, Turkey
| | - Selen Işik-Ulusoy
- Department of Psychiatry, School of Medicine, Baskent University, Konya Research Hospital, Konya, Turkey
| | - Öznur Kal
- Department of Internal Medicine, Nephrology, School of Medicine, Baskent University, Konya Research Hospital, Konya, Turkey
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The relation between exercise and glaucoma in a South Korean population-based sample. PLoS One 2017; 12:e0171441. [PMID: 28187143 PMCID: PMC5302806 DOI: 10.1371/journal.pone.0171441] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 12/31/2016] [Indexed: 01/30/2023] Open
Abstract
Purpose To investigate the association between exercise and glaucoma in a South Korean population-based sample. Design Population-based, cross-sectional study. Participants A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008–2011 Korean National Health and Nutrition Examination Survey. Methods Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Main outcome measure(s) Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Results Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16–9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03–2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67–21.94) but not in women (OR 0.96 95% CI: 0.23–3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09–2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25–3.85 for high intensity versus moderate intensity). Conclusion In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women.
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12
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Guo VY, Chan JCN, Chung H, Ozaki R, So W, Luk A, Lam A, Lee J, Zee BCY. Retinal Information is Independently Associated with Cardiovascular Disease in Patients with Type 2 diabetes. Sci Rep 2016; 6:19053. [PMID: 26754623 PMCID: PMC4709555 DOI: 10.1038/srep19053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 12/04/2015] [Indexed: 11/30/2022] Open
Abstract
To evaluate the association between a series of retinal information and cardiovascular disease (CVD) and to evaluate whether this association is independent of traditional CVD risk factors in type 2 diabetes patients, we undertook an age-sex matched case-control study with 79 CVD cases and 150 non-CVD controls. All the participants underwent standardized physical examinations and retinal imaging. Retinal information was extracted from the retinal images using a semi-automatic computer program. Three stepwise logistic regression models were evaluated: model 1 with cardiovascular risk factors only; model 2 with retinal information only and model 3 with both cardiovascular risk factors and retinal information. The areas under the receiver operating characteristic curves (AUCs) were used to compare the performances of different models. Results showed that the AUCs were 0.692 (95%CI: 0.622−0.761) and 0.661 (95%CI: 0.588−0.735) for model 1 and model 2, respectively. In addition, model 3 had an AUC of 0.775 (95%CI: 0.716−0.834). Compared to the previous two models, the AUC of model 3 increased significantly (p < 0.05 in both comparisons). In conclusion, retinal information is independently associated with CVD in type 2 diabetes. Further work is needed to validate the translational value of applying retinal imaging analysis into clinical practice.
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Affiliation(s)
- Vivian Yawei Guo
- Division of Biostatistics, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.,Department of Family Medicine and Primary Care, The University of Hong Kong, Hong Kong, China
| | - Juliana Chung Ngor Chan
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China.,Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China.,Asia Diabetes Foundation, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China
| | - Harriet Chung
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China
| | - Risa Ozaki
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China
| | - Wingyee So
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China
| | - Andrea Luk
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Hong Kong, China
| | - Augustine Lam
- Department of Family Medicine, New Territories East Cluster, Hospital Authority (Ma On Shan Family Medicine Centre), Hong Kong, China
| | - Jack Lee
- Division of Biostatistics, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Benny Chung-Ying Zee
- Division of Biostatistics, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.,Clinical Trials and Biostatistics Lab, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
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Sander BP, Collins MJ, Read SA. The effect of topical adrenergic and anticholinergic agents on the choroidal thickness of young healthy adults. Exp Eye Res 2014; 128:181-9. [PMID: 25304219 DOI: 10.1016/j.exer.2014.10.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 01/30/2023]
Abstract
The human choroid is capable of rapidly changing its thickness in response to a variety of stimuli. However little is known about the role of the autonomic nervous system in the regulation of the thickness of the choroid. Therefore, we investigated the effect of topical parasympatholytic and sympathomimetic agents upon the choroidal thickness and ocular biometrics of young healthy adult subjects. Fourteen subjects (mean age 27.9 ± 4 years) participated in this randomized, single-masked, placebo-controlled study. Each subject had measurements of choroidal thickness (ChT) and ocular biometrics of their right eye taken before, and then 30 and 60 min following the administration of topical pharmacological agents. Three different drugs: 2% homatropine hydrobromide, 2.5% phenylephrine hydrochloride and a placebo (0.3% hydroxypropyl methylcellulose) were tested in all subjects; each on different days (at the same time of the day) in randomized order. Participants were masked to the pharmacological agent being used at each testing session. The instillation of 2% homatropine resulted in a small but significant increase in subfoveal ChT at 30 and 60 min after drug instillation (mean change 7 ± 3 μm and 14 ± 2 μm respectively; both p < 0.0001). The parafoveal choroid also exhibited a similar magnitude, significant increase in thickness with time after 2% homatropine (p < 0.001), with a mean change of 7 ± 0.3 μm and 13 ± 1 μm (in the region located 0.5 mm from the fovea center), 6 ± 1 μm and 12.5 ± 1 μm (1 mm from the fovea center) and 6 ± 2 μm and 12 ± 2 μm (1.5 mm from the fovea center) after 30 and 60 min respectively. Axial length decreased significantly 60 min after homatropine (p < 0.01). There were also significant changes in lens thickness (LT) and anterior chamber depth (ACD) (p < 0.05) associated with homatropine instillation. No significant changes in choroidal thickness, or ocular biometrics were found after 2.5% phenylephrine or placebo at any examination points (p > 0.05). In human subjects, significant increases in subfoveal and parafoveal choroidal thickness occurred after administration of 2% homatropine and this implies an involvement of the parasympathetic system in the control of choroidal thickness in humans.
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Affiliation(s)
- Beata P Sander
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Room B562, O Block, Victoria Park Road, Kelvin Grove, 4059 Brisbane, Queensland, Australia.
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Room B562, O Block, Victoria Park Road, Kelvin Grove, 4059 Brisbane, Queensland, Australia
| | - Scott A Read
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Room B562, O Block, Victoria Park Road, Kelvin Grove, 4059 Brisbane, Queensland, Australia
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Retinal microvascular structure and function in patients with risk factors of atherosclerosis and coronary artery disease. Atherosclerosis 2014; 233:478-484. [PMID: 24530782 DOI: 10.1016/j.atherosclerosis.2013.12.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 12/02/2013] [Accepted: 12/02/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Retinal microvascular signs are markers of cardiovascular disease risk. There are limited data, on relationships between retinal microvascular signs and retinal microvascular endothelial function. We sought to determine the relationship of retinal vascular signs with retinal microvascular endothelial function in patients with or at high risk of coronary artery disease. METHODS Participants with atherosclerosis risk factors and coronary disease (n=258; mean age 57±11 years) were recruited to have static and dynamic retinal vascular assessment. Retinal arteriolar dilatation in response to flicker light (FI-RAD) was measured using the Digital Vessel Analyser and expressed as percentage increase over baseline diameter. Static retinal photographs were acquired utilising a digital fundus camera for measurement of central retinal artery and vein equivalent (CRAE and CRVE), arteriovenous nicking (AVN) and focal arteriolar narrowing (FAN). RESULTS Intra-class correlation coefficient was 0.82 for flicker-light induced retinal arteriolar dilatation. There were modest associations in retinal vascular measurements between eyes. For each 10 μm decrease in retinal arteriolar diameter, the absolute increase in FI-RAD was 0.28% (95% CI 0.11, 0.45; p=0.002) independent of age, gender and atherosclerosis risk factors. AVN and FAN were associated with attenuated FI-RAD (β=-0.67%; 95% CI -1.20, -0.15; p=0.012) and (β=-0.83%; 95% CI -1.44, -0.23; p=0.007) respectively after adjustment for age and gender. CONCLUSION Assessment of retinal microvascular endothelial function is reproducible and correlated with retinal microvascular structure and signs, independent of atherosclerosis risk factors. Assessment of retinal vascular structure and function may provide insights into atherosclerotic disease.
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15
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Harazny JM, Schmieder RE, Welzenbach J, Michelson G. Local application of tropicamide 0.5% reduces retinal capillary blood flow. Blood Press 2013; 22:371-6. [PMID: 23597124 DOI: 10.3109/08037051.2013.782956] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Scanning laser Doppler flowmetry (SLDF) plays an important role in the study of arterial hypertension, diabetes and stroke. The technology enables non-invasive measurement of the retinal capillary perfusion (RCF), retinal haemodynamics and arteriolar morphology in human. The values can be measured in mydriasis or in non-mydriatic eyes. It is not clear whether the using of vasoactive mydriatica for pupil dilation affects the measured parameters in retina. Acetylcholine, a vasoactive neurotransmitter in human retina, affects the contractility of pericytes using muscarinic receptors and stimulates endothelial synthesis of nitric oxide (NO). We examined whether blockade of the retinal cholinergic receptors by tropicamide affects the RCF. METHODS We measured RCF in both eyes of 13 healthy subjects before and 30 min after the local application of one drop of 0.5% tropicamide to the right eye. The mean age of the group was 44 ± 14 years. The left eye was used as control. RCF was measured by Heidelberg retina flowmetry. RESULTS Thirty minutes after local application of one drop of 0.5% tropicamide to the right eye RCF decreased significantly (p = 0.001) by 31.9 ± 13% but did not change in the control eye. The maximal decrease was observed 20 min after application of the tropicamide. CONCLUSION Locally administered tropicamide profoundly affects the RCF. Thus pupil dilatation impairs any assessment of retinal microcirculation.
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Affiliation(s)
- Joanna M Harazny
- Ophthalmology Department Friedrich-Alexander University , Erlangen , Germany
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16
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Zhang Y, San Emeterio Nateras O, Peng Q, Rosende CA, Duong TQ. Blood flow MRI of the human retina/choroid during rest and isometric exercise. Invest Ophthalmol Vis Sci 2012; 53:4299-305. [PMID: 22661466 DOI: 10.1167/iovs.11-9384] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate blood flow (BF) in the human retina/choroid during rest and handgrip isometric exercise using magnetic resonance imaging (MRI). METHODS Four healthy volunteers (25-36 years old) in multiple sessions (1-3) on different days. MRI studies were performed on a 3-Tesla scanner using a custom-made surface coil (7×5cm in diameter) at the spatial resolution of 0.5×0.8×6.0 mm. BF was measured using the pseudo-continuous arterial-spin-labeling technique with background suppression and turbo-spin-echo acquisition. During MRI, subjects rested for 1 minute followed by 1 minute of handgrip, repeating three times, while maintaining stable eye fixation on a target with cued eye blinks at the end of each data acquisition (every 4.6 seconds). RESULTS Robust BF of the unanesthetized human retina/choroid was detected. Basal BF in the posterior retina/choroid was 149±48 mL/100 mL/min with a mean heart rate of 60±5 beats per minute, mean arterial pressure of 78±5 mm Hg, ocular perfusion pressure of 67±4 mm Hg at rest (mean±SD, n=4 subjects). Handgrip significantly increased retina/choroid BF by 25%±7%, heart rate by 19%±8%, mean arterial pressure by 22%±5% (measured at the middle of the handgrip task), and ocular perfusion pressure by 25%±6% (averaged across the entire handgrip task) (P<0.01), but did not change intraocular pressure, arterial oxygen saturation, end-tidal CO2, and respiration rate (P>0.05). CONCLUSIONS This study demonstrates a novel MRI application to image quantitative BF of the human retina/choroid during rest and isometric exercise. Retina/choroid BF increases during brief handgrip exercise, paralleling increases in mean arterial pressure. Handgrip exercise changes ocular perfusion pressure free of potential drug side effect and can be done in the MRI scanner. MRI offers quantitative BF with large field of view without depth limitation, potentially providing insights into retinal pathophysiology.
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Affiliation(s)
- Yi Zhang
- Research Imaging Institute, Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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17
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Gopinath B, Wang JJ, Flood VM, Burlutsky G, Wong TY, Mitchell P. The associations between blood levels of homocysteine, folate, vitamin B12, and retinal vascular caliber. Am J Ophthalmol 2009; 148:902-9. [PMID: 19796756 DOI: 10.1016/j.ajo.2009.07.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/30/2009] [Accepted: 07/16/2009] [Indexed: 11/18/2022]
Abstract
PURPOSE To assess the association of total serum levels of homocysteine (tHcy), folate, and vitamin B12 with retinal vascular caliber in older adults. DESIGN Cross-sectional, population-based study. METHODS One thousand seven hundred and seventy-two of 2334 Blue Mountains Eye Study participants examined had fundus photographs taken and retinal arteriolar and venular caliber measured using computer-assisted techniques and summarized. Serum folate and vitamin B12 levels and tHcy were determined from venous blood samples. Linear regression models adjusting for age, gender, mean arterial blood pressure, smoking, and diabetes were used to assess whether serum levels of tHcy, folate, and vitamin B12 were associated with retinal arteriolar and venular caliber. RESULTS Arteriolar and venular caliber was not associated with tHcy in the total population. Further analysis demonstrated a significant serum homocysteine-gender interaction (P = .04). A significant inverse association between tHcy and arteriolar caliber was found in men only (P = .03), with a threshold detected at a level of 17 micromol/l. Above this threshold, increasing tHcy was linearly associated with narrower arteriolar caliber (0.86 microm reduction per 1.0 micromol/l increase in tHcy) in men, but no significant association was found below this threshold. No significant associations were observed between serum folate or vitamin B12 levels and either retinal vessel caliber. CONCLUSIONS Retinal vascular caliber is associated with tHcy in men but not women. This finding may reflect the stronger association between blood pressure and tHcy in men than in women.
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Affiliation(s)
- Bamini Gopinath
- Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales, Australia
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Aslam T, Fleck B, Patton N, Trucco M, Azegrouz H. Digital image analysis of plus disease in retinopathy of prematurity. Acta Ophthalmol 2009; 87:368-77. [PMID: 19210329 DOI: 10.1111/j.1755-3768.2008.01448.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An accurate assessment of retinopathy of prematurity (ROP) is essential in ensuring correct and timely treatment of this potentially blinding condition. Current modes of assessment are based upon clinical grading by expert examination of retinal changes. However, this may be subjective, unreliable and difficult and there has been significant interest in alternative means of measurement. These have been made possible through technological advancements in image capture and analysis as well as progress in clinical research, highlighting the specific importance of plus disease in ROP. Progress in these two fields has highlighted the potential for digital image analysis of plus disease to be used as an objective, reliable and valid measurement of ROP. The potential for clinical and scientific advancement through this method is argued and demonstrated in this article. Along with the potential benefits, there are significant challenges such as in image capture, segmentation, measurement of vessel width and tortuosity; these are also addressed. After discussing and explaining the challenges involved, the research articles addressing digital image analysis of ROP are critically reviewed. Benefits and limitations of the currently published techniques for digital ROP assessment are discussed with particular reference to the validity and reliability of outcome measures. Finally, the general limitations of current methods of analysis are discussed and more diverse potential areas of development are discussed.
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Affiliation(s)
- Tariq Aslam
- Princess Alexandra Eye Pavilion, Chalmers Street, Edinburgh, UK.
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20
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Abstract
PURPOSE To determine pathways of sympathetic nerves from the orbital apex to the eyelids in human cadaver tissue using immunohistochemistry. METHODS Human cadaver orbit tissue was sectioned and immunolabeled with a monoclonal antityrosine hydroxylase antibody. RESULTS In the orbital apex, the nasociliary, frontal, lacrimal, and maxillary branches of the trigeminal nerve demonstrated intense staining upon entering the orbit. Immunoreactive axons from the nasociliary and frontal nerves were observed to join the extraocular motor nerves in the posterior orbit. A plexus of immunolabeled nerves was observed to accompany the ophthalmic artery as it entered the orbital apex. The ophthalmic artery and its branches throughout the orbit demonstrated staining of nerve fibers in the peripheral muscularis. The nasociliary nerve contributed sympathetic branches to the ciliary ganglion. Nerves passing through the ciliary ganglion and a few ganglion cell bodies demonstrated mild to moderate tyrosine hydroxylase reactivity. Axons within the short and long ciliary nerves demonstrated strong tyrosine hydroxylase reactivity and were observed to enter the posterior sclera and the suprachoroidal space. The lacrimal gland demonstrated mild pericapillary staining and occasional stromal nerve fibers reactive to the antityrosine hydroxylase antibody. Müller muscle and the inferior tarsal muscle possessed a strong tyrosine hydroxylase-reactive nerve supply that appeared to originate from the anterior terminal branches of the nasociliary and lacrimal nerves. CONCLUSIONS Sympathetic nerves enter the orbit via the first and second divisions of the trigeminal nerve and a plexus of nerves surrounding the ophthalmic artery. Extraocular motor nerves receive a sympathetic nerve supply from the sensory nerves in the posterior orbit. Some ciliary ganglion cell bodies demonstrated tyrosine hydroxylase-like reactivity, suggesting a sympathetic modulatory role for the ciliary ganglion. Sympathetics innervate ocular structures via the posterior ciliary nerves. Sympathetic axons travel anteriorly in the orbit via the nasociliary and lacrimal nerves to innervate the sympathetic eyelid muscles. Sympathetic nerves also travel with the frontal branch of the ophthalmic nerve to innervate the forehead skin. The ophthalmic artery and all of its branches contain a perivascular sympathetic nerve supply that may be involved in regulation of blood flow to ocular and orbital structures.
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Grosso A, Veglio F, Porta M, Grignolo FM, Wong TY. Hypertensive retinopathy revisited: some answers, more questions. Br J Ophthalmol 2005; 89:1646-54. [PMID: 16299149 PMCID: PMC1772998 DOI: 10.1136/bjo.2005.072546] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2005] [Indexed: 11/03/2022]
Abstract
Hypertension is associated with cardiovascular risk and systemic target organ damage. Retinopathy is considered one of the indicators of target organ damage. This review focuses on recent studies on hypertensive retinopathy and their implications for clinical care. Early recognition of hypertensive retinopathy signs remains an important step in the risk stratification of hypertensive patients.
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Affiliation(s)
- A Grosso
- Department of Clinical Physiopathology, Ophthalmology Section, Turin University, Via Juvarra, 19, 10122 Turin, Italy.
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Patton N, Aslam TM, MacGillivray T, Deary IJ, Dhillon B, Eikelboom RH, Yogesan K, Constable IJ. Retinal image analysis: concepts, applications and potential. Prog Retin Eye Res 2005; 25:99-127. [PMID: 16154379 DOI: 10.1016/j.preteyeres.2005.07.001] [Citation(s) in RCA: 257] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
As digital imaging and computing power increasingly develop, so too does the potential to use these technologies in ophthalmology. Image processing, analysis and computer vision techniques are increasing in prominence in all fields of medical science, and are especially pertinent to modern ophthalmology, as it is heavily dependent on visually oriented signs. The retinal microvasculature is unique in that it is the only part of the human circulation that can be directly visualised non-invasively in vivo, readily photographed and subject to digital image analysis. Exciting developments in image processing relevant to ophthalmology over the past 15 years includes the progress being made towards developing automated diagnostic systems for conditions, such as diabetic retinopathy, age-related macular degeneration and retinopathy of prematurity. These diagnostic systems offer the potential to be used in large-scale screening programs, with the potential for significant resource savings, as well as being free from observer bias and fatigue. In addition, quantitative measurements of retinal vascular topography using digital image analysis from retinal photography have been used as research tools to better understand the relationship between the retinal microvasculature and cardiovascular disease. Furthermore, advances in electronic media transmission increase the relevance of using image processing in 'teleophthalmology' as an aid in clinical decision-making, with particular relevance to large rural-based communities. In this review, we outline the principles upon which retinal digital image analysis is based. We discuss current techniques used to automatically detect landmark features of the fundus, such as the optic disc, fovea and blood vessels. We review the use of image analysis in the automated diagnosis of pathology (with particular reference to diabetic retinopathy). We also review its role in defining and performing quantitative measurements of vascular topography, how these entities are based on 'optimisation' principles and how they have helped to describe the relationship between systemic cardiovascular disease and retinal vascular changes. We also review the potential future use of fundal image analysis in telemedicine.
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Affiliation(s)
- Niall Patton
- Lions Eye Institute, 2, Verdun Street, Nedlands, WA 6009, Australia.
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Patton N, Aslam T, Macgillivray T, Pattie A, Deary IJ, Dhillon B. Retinal vascular image analysis as a potential screening tool for cerebrovascular disease: a rationale based on homology between cerebral and retinal microvasculatures. J Anat 2005; 206:319-48. [PMID: 15817102 PMCID: PMC1571489 DOI: 10.1111/j.1469-7580.2005.00395.x] [Citation(s) in RCA: 507] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The retinal and cerebral microvasculatures share many morphological and physiological properties. Assessment of the cerebral microvasculature requires highly specialized and expensive techniques. The potential for using non-invasive clinical assessment of the retinal microvasculature as a marker of the state of the cerebrovasculature offers clear advantages, owing to the ease with which the retinal vasculature can be directly visualized in vivo and photographed due to its essential two-dimensional nature. The use of retinal digital image analysis is becoming increasingly common, and offers new techniques to analyse different aspects of retinal vascular topography, including retinal vascular widths, geometrical attributes at vessel bifurcations and vessel tracking. Being predominantly automated and objective, these techniques offer an exciting opportunity to study the potential to identify retinal microvascular abnormalities as markers of cerebrovascular pathology. In this review, we describe the anatomical and physiological homology between the retinal and cerebral microvasculatures. We review the evidence that retinal microvascular changes occur in cerebrovascular disease and review current retinal image analysis tools that may allow us to use different aspects of the retinal microvasculature as potential markers for the state of the cerebral microvasculature.
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Affiliation(s)
- Niall Patton
- Princess Alexandra Eye Pavilion, Chalmers Street, Edinburgh, UK.
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Wong TY, Wang JJ, Rochtchina E, Klein R, Mitchell P. Does refractive error influence the association of blood pressure and retinal vessel diameters? The Blue Mountains Eye Study. Am J Ophthalmol 2004; 137:1050-5. [PMID: 15183789 DOI: 10.1016/j.ajo.2004.01.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2004] [Indexed: 11/16/2022]
Abstract
PURPOSE To determine if refractive errors influence the association of blood pressure and retinal vessel diameters. DESIGN Population-based, cross-sectional study. METHODS Retinal photographs from the right eyes of participants (n = 3,654, aged 49+ years) in the Blue Mountains Eye Study taken during baseline examinations (1992 to 1994) were digitized. The diameter of all retinal vessels located half to one disk diameter from the disk margin was measured using a computer-assisted imaging program. These measurements were combined to provide the average diameters of retinal arterioles and venules of that eye, and the ratio of their diameters, the arteriole-to-venule ratio (AVR). The association of blood pressure and retinal vessel diameters was analyzed before and after correction for refraction using the Bengtsson formula. RESULTS Before correction, each 10-mm Hg increase in mean arterial blood pressure was associated with a 3.7-microm (95% confidence interval [CI], 3.2-4.3) decrease in arteriolar diameter and a 0.9-microm (95% CI, 0.3-0.9) decrease in venular diameter. After correction for refraction, each 1-mm Hg increase in mean arterial blood pressure was associated with a 3.7-microm (95% CI, 3.2-4.2) decrease in arteriolar diameter and a 0.8-microm (95% CI, 0.3-0.9) decrease in venular diameter. Refraction was not associated with the AVR and had no effect on the association of blood pressure and AVR. CONCLUSION Refraction had no appreciable effect on the association of blood pressure and retinal vessel diameters or on the AVR. Correction for refraction is important for quantifying absolute retinal vessel caliber, but may not be particularly important in epidemiologic studies investigating the association of generalized retinal arteriolar narrowing and hypertension.
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Affiliation(s)
- Tien Yin Wong
- Centre for Eye Research Australia, University of Melbourne, East Melbourne
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25
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Yu HG, Chung H, Yoon TG, Yum KW, Kim HJ. Stellate ganglion block increases blood flow into the optic nerve head and the peripapillary retina in human. Auton Neurosci 2003; 109:53-7. [PMID: 14638313 DOI: 10.1016/j.autneu.2003.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of stellate ganglion block (SGB) on the blood flow of the optic nerve head (ONH) and the peripapillary retina, which plays an important role in the pathogenesis of a major blinding disease, e.g. glaucoma, are unclear. The aim of this study was to evaluate the effects of a sympathetic block on the blood flow of the ONH and the peripapillary retina. Heidelberg Retinal Flowmetry, which is a system incorporating a noninvasive confocal scanning laser Doppler flow meter, was used to measure the retinal blood flow. A unilateral stellate ganglion block was performed in 11 healthy subjects. The retinal blood flows were measured before, 30 and 120 min after SGB. On each occasion, three scans were obtained and the blood flow was analyzed. The systemic blood pressure (BP) and the intraocular pressure (IOP) were also measured at the set time points. The blood flow of the ONH and the peripapillary retina of the ipsilateral retina was significantly increased (P=0.001) by 106.8% and 98.7%, respectively, 30 min after SGB without accompanying significant changes in BP and IOP when compared to their baseline values; while those of the contralateral eyes did not change. The effect of SGB on blood flow in these areas disappeared 120 min after SGB. In conclusion, SGB may have a beneficial effect on ocular diseases associated with ischemia of the ONH and the peripapillary retina, e.g. glaucoma.
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Affiliation(s)
- Hyeong-Gon Yu
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
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26
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Leung H, Wang JJ, Rochtchina E, Tan AG, Wong TY, Hubbard LD, Klein R, Mitchell P. Computer-assisted retinal vessel measurement in an older population: correlation between right and left eyes. Clin Exp Ophthalmol 2003; 31:326-30. [PMID: 12880458 DOI: 10.1046/j.1442-9071.2003.00661.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study assessed the correlation between computer-assisted retinal vessel measurements of right and left eyes, from subjects in a defined, community-based older population. Retinal photographs from participants in the Blue Mountains Eye Study were digitized. All retinal arterioles and venules located 0.5-1.0 disc diameters from the optic disc margin were identified and a computer program measured their diameters. Pearson correlation (R2) statistic was used to assess the correlation in a random subsample of 1546 images. Substantial correlation between right and left eye measurements was found for summary indices of retinal arterioles (R2 = 0.70) and venules (R2 = 0.77). Higher correlation was found for intragrader (R2 0.75-079) than for intergrader assessment (R2 0.67-0.72). Moderate correlation was found in arteriole-to-venule ratio assessed by the same (R2 = 0.57) or different (R2 = 0.52) graders. Measurements from one eye can thus adequately represent the retinal vessel diameters of a person.
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Affiliation(s)
- Harry Leung
- Centre for Vision Research, Department of Ophthalmology, University of Sydney, Sydney, New South Wales, Australia
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27
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Couper DJ, Klein R, Hubbard LD, Wong TY, Sorlie PD, Cooper LS, Brothers RJ, Nieto FJ. Reliability of retinal photography in the assessment of retinal microvascular characteristics: the Atherosclerosis Risk in Communities Study. Am J Ophthalmol 2002; 133:78-88. [PMID: 11755842 DOI: 10.1016/s0002-9394(01)01315-0] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE Retinal microvascular characteristics, as graded from retinal photography, have been shown to predict stroke. We evaluated the reliability of retinal photographic grading in the Atherosclerosis Risk in Communities Study. DESIGN Cohort study. METHODS Retinal photographs were taken of all subjects who attended the third Atherosclerosis Risk in Communities Study examination (1993 to 1995). These were graded using standardized protocols. Focal retinal characteristics were graded using a "light box" system. Generalized retinal arteriolar narrowing was quantified from computer-assisted measurements of digitized photographs. Two sub-studies were conducted to investigate the reliability of these grading methods. In the Individual Variability Study, selected subjects (n = 206) had two retinal photographs taken on one day, and a further one or two photographs taken 3 weeks later. In the Grader Variability Study, a stratified random sample of photographs had repeat retinal grading (n = 495 photographs for light box grading; n = 276 photographs for computer-assisted grading). RESULTS Reliability of the computer-assisted quantification of generalized retinal arteriolar narrowing was high in both studies (reliability coefficients 0.64 to 0.69 for Individual Variability Study, and 0.79 to 0.83 for the Grader Variability Study). There was more variability for focal abnormalities graded using the light box system. Variability for Individual Variability Study (same individuals, repeat photographs) tended to be greater than for the Grader Variability Study (same photographs, repeat gradings). CONCLUSION Retinal microvascular characteristics, especially computer-assisted quantification of generalized retinal arteriolar narrowing, can be ascertained reliably by standardized photographic grading methods, supporting the validity of their associations with cardiovascular disease. However, these characteristics appear to vary somewhat between eyes and over time in a single individual.
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Affiliation(s)
- David J Couper
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina 27514, USA.
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28
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Wong TY, Klein R, Klein BE, Tielsch JM, Hubbard L, Nieto FJ. Retinal microvascular abnormalities and their relationship with hypertension, cardiovascular disease, and mortality. Surv Ophthalmol 2001; 46:59-80. [PMID: 11525792 DOI: 10.1016/s0039-6257(01)00234-x] [Citation(s) in RCA: 363] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Retinal microvascular abnormalities, such as generalized and focal arteriolar narrowing, arteriovenous nicking and retinopathy, reflect cumulative vascular damage from hypertension, aging, and other processes. Epidemiological studies indicate that these abnormalities can be observed in 2-15% of the nondiabetic general population and are strongly and consistently associated with elevated blood pressure. Generalized arteriolar narrowing and arteriovenous nicking also appear to be irreversible long-term markers of hypertension, related not only to current but past blood pressure levels as well. There are data supporting an association between retinal microvascular abnormalities and stroke, but there is no convincing evidence of an independent or direct association with atherosclerosis, ischemic heart disease, or cardiovascular mortality. New computer-related imaging methods are currently being developed to detect the presence and severity of retinal arteriolar narrowing and other microvascular characteristics. When reliably quantified, retinal microvascular abnormalities may be useful as risk indicators for cerebrovascular diseases.
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Affiliation(s)
- T Y Wong
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53705-2397, USA.
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29
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Movaffaghy A, Chamot SR, Petrig BL, Riva CE. Blood flow in the human optic nerve head during isometric exercise. Exp Eye Res 1998; 67:561-8. [PMID: 9878218 DOI: 10.1006/exer.1998.0556] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Investigating blood flow autoregulation in the optic nerve is important to understand the physiopathology of various ocular diseases such as glaucoma. This investigation requires that one establishes the relationship between optic nerve blood flow and perfusion pressure. Previous work has documented the effect of lowering the perfusion pressure on optic nerve blood flow. The purpose of the present study was to investigate the effect of elevated perfusion pressure on blood flow in this tissue. Laser Doppler flowmetry was applied to measure relative mean velocity, volume and flux of red blood cells in the tissue of the optic nerve head. These parameters were measured in 13 subjects during isometric exercise consisting of squatting. In the range of perfusion pressures from 56+/-4 to 80+/-5 mmHg (30+/-8%), there was no significant variation of mean velocity, volume and flux of red blood cells, but vascular resistance increased by about 50%. Intraocular pressure was increased significantly above baseline at the end of squatting and decreased during recovery. The results suggest that the maintenance of constant blood flow is achieved by an increase in vascular resistance taking place either at the arterioles feeding or at the veins draining the blood from the ONH or at the ophthalmic artery and/or vessels between this artery and the site of LDF measurements. Combining the results of this study with those of a previous one where perfusion pressure was decreased by increasing the intraocular pressure, we show the entire relationship between perfusion pressure and optic nerve blood flow in man.
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Affiliation(s)
- A Movaffaghy
- Institut de Recherche en Ophtalmologie, Sion, Switzerland
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30
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Hill DW. Immediate response of retinal vessels to isometric muscle contraction. Eye (Lond) 1998; 12 ( Pt 1):104-10. [PMID: 9614525 DOI: 10.1038/eye.1998.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Isometric muscle contraction results in a rise in systemic blood pressure (BP) and constriction of retinal arterioles. The responses in the anaesthetised cat have been studied to provide further insight into the results of human studies. Constriction (median 3.43% of control values) and dilatation (median 4.17% of control values) were observed; the onset of constriction was delayed by 4 s compared with dilatation. There was spatial and temporal variation in the observed calibre changes, and inter-experimental variation in the calibre change/BP ratio. It is concluded that the response of retinal arterioles of measurable size is not unified, and that the two modes of response differ in mechanism.
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Affiliation(s)
- D W Hill
- Western General Hospital, Edinburgh, UK
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31
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Forcier P, Kergoat H, Lovasik JV. Macular hemodynamic responses to short-term acute exercise in young healthy adults. Vision Res 1998; 38:181-6. [PMID: 9474388 DOI: 10.1016/s0042-6989(97)00147-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We investigated the effects of vigorous exercise on blood flow in the macular vasculature. The velocity and density of entoptically viewed leukocytes in the paramacular retinal capillaries were measured with an Oculix BFS-2000 blue field simulator in 18 healthy adults first at rest, and then after 20 min of exercise. Exercise typically increased the density of leukocytes with more variable effects on their velocity. When leukocyte velocity and density were factored together, macular blood flow increased only marginally after exercise. We conclude that retinal blood flow in the macula is subject to the influence of autoregulatory mechanisms presumably to sustain normal central visual function during increased systemic blood flow.
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Affiliation(s)
- P Forcier
- Ecole d'optométrie, Université de Montréal, Centre-Ville, Québec, Canada
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32
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Dumskyj MJ, Aldington SJ, Dore CJ, Kohner EM. The accurate assessment of changes in retinal vessel diameter using multiple frame electrocardiograph synchronised fundus photography. Curr Eye Res 1996; 15:625-32. [PMID: 8670765 DOI: 10.3109/02713689609008902] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE Detection and precise quantification of changes in retinal vessel diameter by image analysis techniques is important in a number of fields of research. The retinal vessels have been shown to exhibit pulse related changes in diameter. These may need to be taken into account when studying diameter changes due to other causes. This study examined the effect of using multiple fundus photographs with and without electrocardiographic synchronisation on the size and statistical significance of changes in mean retinal vessel diameter. METHODS Twelve fundus photographs spaced throughout the cardiac cycle by electrocardiographic synchronisation were taken in 10 normal volunteers: (a) at rest, (b) during isometric exercise, and (c) during oxygen inhalation. Vessel diameters were measured using a computer assisted image analysis system. Subsequently smaller sample sizes, with and without electrocardiograph synchronisation were modeled from the available data. RESULTS With a group of ten subjects six or more electrocardiograph synchronised photographs enable reliable detection of small diameter changes (1.4%) induced by isometric exercises while other methods either failed to detect change or were unreliable at doing so. With six subjects twelve synchronised photographs were required to reliably detect a change of the same magnitude. Larger diameter changes (5.4%) were detected by any method including a single unsynchronised photograph. CONCLUSIONS Multiple frame electrocardiograph synchronized fundus photography permits more accurate detection of small changes in retinal vessel diameter.
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Affiliation(s)
- M J Dumskyj
- Department of Medicine and Department of Medical Statistics, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Ménage MJ, Robinson JC, Kaufman PL, Sponsel WE. Retinal blood flow after superior cervical ganglionectomy: a laser Doppler study in the cynomolgus monkey. Br J Ophthalmol 1994; 78:49-53. [PMID: 8110700 PMCID: PMC504691 DOI: 10.1136/bjo.78.1.49] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
There is a conflicting literature regarding the possible presence of adrenergic innervation of the retinal circulation. The effect of a histologically confirmed left superior cervical ganglionectomy on the total retinal blood flow in eight anaesthetised female cynomolgus monkeys was determined. Near total unilateral ocular sympathetic denervation was confirmed by ipsilateral miosis, supersensitivity of pupillary dilatation to topical phenylephrine and pupillary hyporesponsiveness to topical hydroxyamphetamine. Retinal vein diameters were measured from monochromatic photographs, maximum red cell velocities (Vmax) were measured with a helium-neon laser, using a bidirectional laser Doppler velocimeter technique, and the total retinal blood flow in each eye was determined by summation of measurements of flow in individual retinal veins. Mean (SEM) total retinal blood flow was 32.93 (1.49) and 30.41 (1.86) microliters/min in the eight sympathectomised and normal eyes respectively; the 9% (5%) difference was not statistically significant. Our study suggests that pharmacologically confirmed sympathetic denervation has little if any effect on resting total retinal blood flow.
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34
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Hill DW, Lanigan LP, Clark CV. Age-related normal tolerance intervals for retinal vascular response to systemic autonomic nerve stimulation. Eye (Lond) 1991; 5 ( Pt 5):620-6. [PMID: 1794431 DOI: 10.1038/eye.1991.108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This study establishes the age-adjusted tolerance intervals for retinal vascular responses to sustained handgrip contraction (a test of sympathetic nerve function). Forty adult subjects (mean age: 39.7 +/- 14.1 years, range: 20 to 72 years; 19 males) were included in the final analysis. Mean percentage calibre change in response to sustained handgrip contraction in this population was -5.61% with a significant correlation between subject age and percentage retinal vessel calibre change (p less than 0.001). Mean retinal arteriolar calibre change in response to systemic autonomic stimulation varied significantly with age: between -8.48% at age 20 years and -2.06% at age 70 years with a mean of -5.95% at the mean age of 39.7 years. The standard deviation is 3.04% and the 95% confidence intervals were set between +/-6.17%. This autoregulatory reflex appears to be inversely related to age.
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35
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Lanigan LP, Clark CV, Hill DW. Retinal vessel responses to systemic autonomic stimulation in fellow eyes of patients with retinal vein occlusion. Doc Ophthalmol 1990; 74:269-76. [PMID: 2257771 DOI: 10.1007/bf00145811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The retinal vessel calibre responses to systemic autonomic stimulation were studied in fellow eyes of 11 patients with central retinal vein occlusion (CRVO) and 10 patients with branch retinal vein occlusion (BRVO), using sustained isometric muscle contraction as the stimulus. These vessel responses were compared to those of a control group of 11 subjects of similar ages. The changes in retinal vessel calibre were measured using the Quantimet Image Analyser. There was no significant difference in mean arteriolar constriction during isometric muscle contraction (mean +/- SEM) between the CRVO group (6.0 +/- 1.34%) and the BRVO group (5.4 +/- 0.31%), (p greater than 0.05), and between either of these groups compared with the control group (7.4 +/- 1.20%), (p greater than 0.50). Similarly there was no significant difference in mean venule responses between the groups (CRVO 4.9 +/- 0.48%; BRVO 4.6 +/- 0.63%; control subjects 3.8 +/- 0.90%; p greater than 0.05). The diastolic blood pressure responses were similarly not significantly different between the 3 groups (CRVO 22.3 +/- 1.27, range + 17 to 29 mmHg; BRVO 25.8 +/- 2.9 mmHg, range 18 to 45 mmHg; control subjects 21.3 +/- 1.7 mmHg, range 16 to 35 mmHg), (p greater than 0.10). The implications of the results are discussed.
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Affiliation(s)
- L P Lanigan
- Research Department of Ophthalmology, Royal College of Surgeons of England, London
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Lanigan LP, Birche R, Clark CV, Hill DW. The effect of cervical sympathectomy on retinal vessel responses to systemic autonomic stimulation. Eye (Lond) 1990; 4 ( Pt 1):181-9. [PMID: 2323469 DOI: 10.1038/eye.1990.24] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The retinal vessel calibre responses to systemic sympathetic stimulation, were studied in nine patients (eight male; mean age: 31.7 years; range: 19-58 years) with unilateral disruption of their cervical sympathetic tract. All patients had ipsilateral decreased/absent facial sweating and a Horners syndrome, evidence of unilateral sympathetic denervation. Both eyes of each patient were studied and the results were analysed in two groups: the group of nine sympathectomised eyes and the control group of unaffected fellow eyes. During handgrip contraction there was a significant difference in the mean retinal arteriolar constriction (mean +/- SEM) between the group of sympathectomised eyes (4.6 +/- 0.89%) and control eyes (7.1 +/- 1.13%), p less than 0.01. Similarly, there was a significant difference in mean venule constriction during sustained handgrip contraction between the group of sympathectomised eyes (1.5 +/- 0.67%) and control eyes (4.9 +/- 0.98%), p less than 0.05. There was no significant difference in the mean rise in diastolic blood pressure between the two groups: control eyes +27.9 +/- 2.38 mmHg and sympathectomised eyes +27.8 +/- 2.25 mmHg. There was no correlation between the blood pressure and retinal vessel responses in either group. These results suggest that the sympathetic nervous system plays an integral role in retinal blood flow regulation.
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Affiliation(s)
- L P Lanigan
- Research Department of Ophthalmology, Royal College of Surgeons of England, London
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37
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Lanigan LP, Clark CV, Allawi J, Hill DW, Keen H. Impaired autoregulation of the retinal vasculature and microalbuminuria in diabetes mellitus. Eye (Lond) 1990; 4 ( Pt 1):174-80. [PMID: 2323468 DOI: 10.1038/eye.1990.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The relationship between microalbuminuria and retinal vessel responses to sustained handgrip contraction was studied in a group of 20 diabetic patients. The diabetics were divided into two groups based on their albumin excretion rates (AER): Group 1 (AER less than or equal to 10 mcg/min) consisted of ten diabetic patients, mean age 55.8 +/- 3.9 years (mean +/- SEM); five IDDM and five NIDDM. Group 2 (AER greater than 10 mcg/min) comprised ten diabetic patients: mean age 56.8 +/- 3.04 years; six IDDM and four NIDDM. Both groups were similar in that there were no significant differences between mean age, type of diabetes, mean duration of diabetes, glycaemic control or mean resting blood pressures. Group 2 diabetics had a higher incidence of autonomic dysfunction than Group 1, based on the results of four standard tests of autonomic nerve function. There were significantly decreased retinal vessel responses to sustained handgrip contraction in Group 2 diabetics (mean arteriolar constriction 0.1 +/- 0.32%, and mean venule constriction 1.0% +/- 0.99%) compared with Group 1 diabetics (mean arteriolar constriction 6.9 +/- 1.69%, and mean venule constriction 4.2 +/- 0.05%). Retinopathy was slightly worse in Group 2. The implications of the association of microalbuminuria (AER greater than 10 mcg/min) and loss of retinal vessel reactivity to sustained handgrip contraction are discussed.
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Affiliation(s)
- L P Lanigan
- Research Department of Ophthalmology, Royal College of Surgeons of England, London
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Brinchmann-Hansen O, Myhre K, Sandvik L. Retinal vessel responses to exercise and hypoxia before and after high altitude acclimatisation. Eye (Lond) 1989; 3 ( Pt 6):768-76. [PMID: 2630361 DOI: 10.1038/eye.1989.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Computerised microdensitometry was used to study diameter changes in 93 arterial and 91 venous vessel sites in the retinas of four mountain climbers before and after spending seven weeks in the Himalaya mountains. The vascular response to short-term strenuous exercise was measured at sea level, to acute hypoxia of simulated altitude of 15,000 ft (4,572 m) at rest, and to strenuous exercise while acutely exposed to the same hypoxic condition. Before the mountain exposure, retinal vessels constricted during exercise -1.9% (arteries); -3.3% (veins) and dilated in acute hypoxia 9.4% (arteries); 8.1% (veins). Superimposed exercise on hypoxic dilated arteries reduced the vasodilation (9.4% to 6%). After acclimatisation, the same physical work load at sea level constricted the arteries more (-5.4% vs -1.9%) but did not constrict the veins (0.2% vs -3.3%). Superimposed exercise on hypoxic dilated vessels, excessively dilated both arteries (8.4% vs 6.0%) and veins (13.7% vs 8.4%), compared to changes seen before the mountain sojourn. This study shows that physical conditioning and long adaptation to hypoxia, significantly change the vascular response of the retina to physical activity both in normal atmospheric conditions and during hypoxic stress. High altitude retinal hemorrhages (HARH) were present in one climber, and the study may indicate why HARH is seen often in young and physical well-trained subjects.
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Lanigan LP, Clark CV, Allawi J, Hill DW, Keen H. Intraocular pressure responses to systemic autonomic stimulation in diabetes mellitus. Doc Ophthalmol 1989; 72:141-53. [PMID: 2582995 DOI: 10.1007/bf00156704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The acute changes in intraocular pressure during sustained handgrip contraction (2.5 minutes duration) and the Valsalva manoeuvre (15 seconds duration), both standard tests of autonomic nerve function were studied in 14 diabetic patients and 14 similar aged control subjects. During sustained handgrip contraction, diastolic blood pressure increased by 16.35 +/- 1.87 mmHg in the diabetic patients and 21.36 +/- 0.66 mmHg for the control group. Mean intraocular pressure decreased by 0.71 +/- 0.43 mmHg in the diabetics, p less than 0.05 and 0.64 +/- 0.27 mmHg, p less than 0.01) in the control group. There was no correlation between the blood pressure and the intraocular pressure responses in either group. On release of handgrip contraction, mean recovery intraocular pressure over 5 minutes was significantly lower than mean baseline values for the two groups; control: baseline 14.78 +/- 0.49 to 14.14 +/- 0.67, p less than 0.001 and diabetic: 14.57 +/- 0.65 to 13.86 +/- 0.72, p less than 0.001. During the Valsalva manoeuvre, there was a significant rise in intraocular pressure in the control (+7.85 +/- 0.75 mmHg, p less than 0.001) and the diabetic group (+7.93 +/- 1.18 mmHg, p less than 0.001). 5 minutes after release of intrathoracic pressure, mean recovery intraocular pressure remained significantly below baseline values for the two groups. The Valsalva ratios were in the normal range for the control group (1.21 to 2.2) while 2 diabetics had abnormal ratios.
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Affiliation(s)
- L P Lanigan
- Research Department of Ophthalmology, Royal College of Surgeons of England, London
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40
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Lanigan LP, Clark CV, Allawi J, Hill DW, Keen H. Responses of the retinal circulation to systemic autonomic stimulation in diabetes mellitus. Eye (Lond) 1989; 3 ( Pt 1):39-47. [PMID: 2591597 DOI: 10.1038/eye.1989.6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The retinal vessel calibre responses to systemic sympathetic stimulation, were studied in 22 randomly selected diabetic patients (mean age +/- SEM: 54.7 +/- 2.59 years, range 25-73; 13 IDDM, 9 NIDDM; 4 females), using sustained isometric muscle contraction as the stimulus. At a different session the integrity of the autonomic nerve function in these diabetic patients was assessed using 3 standard tests of autonomic nerve function, based on cardiovascular reflexes. Diabetic patients with an intact autonomic nervous system: Group 1, (n = 11, mean age: 54.9 +/- 4.55 years, 7 IDDM 4 NIDDM) showed a mean arteriolar constriction of 9.2% (SEM 2.89, p less than 0.01) and a mean venule constriction of 5.1% (SEM 1.73, p less than 0.02), for a mean rise in diastolic blood pressure of 23.7 mmHg (SEM 2.19 range: 13-33). There were no significant mean retinal vessel responses however, in diabetics with autonomic dysfunction (Group 2): mean arteriolar constriction of 1.2% (SEM 1.38 p greater than 0.05) and venule constriction of 2.1% (SEM 1.38, p greater than 0.05); for a mean rise in diastolic blood pressure of 19.8 mmHg (SEM 4.49, range: 2-50). There was no correlation between the rise in diastolic blood pressure and the retinal arteriolar constriction in the 2 groups (Group 1:r = 0.45, p greater than 0.01 and Group 2: r = 0.56, p greater than 0.05). Duration, type and control of diabetes were not significantly different between the 2 groups. The severity of retinopathy was slightly worse in Group 2 compared to Group 1. These results point to an association between autonomic neuropathy and failure of regulation of retinal blood flow.
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Affiliation(s)
- L P Lanigan
- Research Department of Ophthalmology, Royal College of Surgeons of England, London
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