scholarly journals Blocked blood vessel model for the development of treatment device of retinal vein occlusion

2019 ◽  
Vol 30 (3) ◽  
pp. 544-553
Author(s):  
Keiko MIWA ◽  
Daisuke MATSUMURA ◽  
Mei SUMIMOTO ◽  
Tomohiro KAWAHARA ◽  
Yasuhiro MORIIZUMI ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Retinal Vein Occlusion ◽  
Vein Occlusion

Angle detection system for crossing compression of retinal artery and vein

2021 ◽  
pp. 1-16
Author(s):  
Chunping Liao ◽  
Xuefang Chen ◽  
Bifu Li ◽  
Xiaofang Zhao ◽  
Li Yu
Keyword(s):  
Blood Vessel ◽  
Retinal Vein Occlusion ◽  
Detection System ◽  
Average Error ◽  
Vein Occlusion ◽  
Retinal Artery ◽  
Point Distance ◽  
Point Detection ◽  
Binary Edge ◽  
Candidate Feature

The crossing compression of retinal artery and vein is closely related to retinal vein occlusion, so detecting the contraction angle of the crossed vein blood vessel can assist to diagnose the retinal vein occlusion diseases. Through pretreating methods such as filtering, enhancement and edge extraction, the binary edge images can be extracted. The candidate feature points can be obtained by the corner point detection method based on chord-to-point distance accumulation (CPDA). The self-adaptive rectangular filter is used to screen out the crossing point of candidate angle, so as to fit the edge curves and figure out the contraction degree of vein. The experimental results show that this algorithm can better detect the contraction degree of crossed vein blood vessel, with an average error remaining at ± 1∘ under different resolutions.

Platelet Coagulant Activities and Retinal Vein Thrombosis

1977 ◽  
Vol 38 (02) ◽  
pp. 0399-0406 ◽  
Author(s):  
Peter N. Walsh ◽  
Richard E. Goldberg ◽  
Richard L. Tax ◽  
Larry E. Magargal
Keyword(s):  
Platelet Aggregation ◽  
Venous Thrombosis ◽  
Retinal Vein Occlusion ◽  
Serotonin Release ◽  
Platelet Factor ◽  
Trigger Mechanism ◽  
Local Conditions ◽  
Plasma Coagulation ◽  
Vein Thrombosis ◽  
Vein Occlusion

SummaryTo determine whether platelets play a role in the pathogenesis of retinal vein occlusion (RVO), platelets and coagulation were evaluated in 28 patients with RVO. Platelet coagulant activities concerned with the initiation and early stages of intrinsic coagulation were 2–4 fold increased in 9 patients with acute primary RVO but not in patients with acute secondary (10 patients) or chronic (9 patients) RVO. Platelet factor 3 activity, platelet aggregation, serotonin release by platelets and plasma coagulation were normal in all patients. Platelets may provide a trigger mechanism for venous thrombosis in the eye when local conditions permit.

Hypercoagulability and High Lipoprotein(a) Levels in Patients with Central Retinal Vein Occlusion

1994 ◽  
Vol 72 (01) ◽  
pp. 039-043 ◽  
Author(s):  
Francesco Bandello ◽  
Silvana Vigano’ D’Angelo ◽  
Mariella Parlavecchia ◽  
Alessandra Tavola ◽  
Patrizia Della Valle ◽  
...  
Keyword(s):  
Retinal Vein Occlusion ◽  
Central Retinal Vein Occlusion ◽  
Specific Treatment ◽  
Fibrin Deposition ◽  
Heparin Cofactor Ii ◽  
Lipoprotein A ◽  
Vein Occlusion ◽  
Acute Event ◽  
D Dimer ◽  
Central Retinal Vein

SummaryA series of coagulation parameters and lipoprotein(a) (Lp(a)) were explored in plasma from 40 patients with central retinal vein occlusion (CRVO, non-ischemic type n = 12; ischemic type n = 28) free of local and systemic predisposing factors, 1 to 12 months after the acute event. Forty age- and sex-matched patients with cataract served as controls. Prothrombin fragment 1.2 (FI.2), D-dimer, FVII:C - but not FVII: Ag - were higher and fibrinogen was lower in CRVO patients than in controls. Patients with non-ischemic CRVO had higher FI .2 and FVII:C and lower heparin cofactor II than patients with ischemic CRVO. Lp(a) levels greater than 300 mg/1 were observed in 12 patients with CRVO and in 4 controls (30% vs 10%, p <0.025). Patients with high Lp(a) - consistently associated with the S2 phenotype - had higher FVII:C, FVII:C/Ag ratio, and fibrinogen than the remaining CRVO patients. Plasma FI.2 and D-dimer correlated fairly in controls (r = 0.41) and patients with normal Lp(a) levels (r = 0.55), but they did not in the group of patients with high Lp(a) (r = 0.19), where the latter parameter was negatively related to D-dimer (r = −0.55). There was no dependence of the abnormalities observed on the time elapsed from vein occlusion. The findings of activated FVII and high FI.2, D-dimer, and Lp(a) are not uncommon in patients with CRVO. Increased thrombin formation with fibrin deposition and impaired fibrinolysis may play a role in the pathophysiology of CRVO and require specific treatment

Prevalence of Factor V Leiden in Young Adults with Retinal Vein Occlusion

1997 ◽  
Vol 77 (01) ◽  
pp. 214-216 ◽  
Author(s):  
Tuuli Linna ◽  
Antti Ylikorkala ◽  
Kimmo E Kontula ◽  
Päivi Puska ◽  
Timo Tervo
Keyword(s):  
Young Adults ◽  
Retinal Vein Occlusion ◽  
Factor V Leiden ◽  
Factor V ◽  
Vein Occlusion

OCT angiography in retinal vein occlusion

2018 ◽  
Vol 60 (3) ◽  
Author(s):  
Maria C. Savastano ◽  
Marco Rispoli ◽  
Bruno Lumbroso
Keyword(s):  
Retinal Vein Occlusion ◽  
Oct Angiography ◽  
Vein Occlusion

Retinal Vascular Occlusive Disorders - Risk Factors

2018 ◽  
Vol 3 (02) ◽  
Author(s):  
Shivcharan Lal Chandravanshi, Sunil Kumar Shrivastava, Priyanka Agnihotri, Smriti Gupta
Keyword(s):  
Risk Factors ◽  
Retinal Vein Occlusion ◽  
Central Retinal Vein Occlusion ◽  
Branch Retinal Vein Occlusion ◽  
Retinal Artery Occlusion ◽  
Artery Occlusion ◽  
Vein Occlusion ◽  
Department Of Ophthalmology ◽  
Retinal Artery ◽  
Central Retinal Vein

Aims and Objective - The aim of the present study is to identify risk factors associated with different retinal vascular occlusive diseases (RVOD), such as central retinal artery occlusion (CRAO), hemi-retinal artery occlusion (HRAO), branch retinal artery occlusion (BRAO), cilioretinal artery occlusion (Cilio-RAO), central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), and hemi-retinal vein occlusion (HRVO). Patients and Method - A cross-sectional study on 114 consecutive subjects, aged 24-96 years who have attended at the outpatient department of ophthalmology at Shyam Shah Medical College, Rewa, MP, were included in the study. The Duration of study was January 2016 to December 2017. Only patients with CRAO, BRAO, HRAO, Cilio-RAO, CRVO, BRVO, and HRVO were included in the study. Other retinal vascular disorders such as diabetic vaso-occlusive disease, anterior and posterior ischemic and non-ischemic neuropathy, hypertensive retinopathy, sickle cell retinopathy, retinal telangiectasia, retinopathy of prematurity, were excluded from study. Results - We have included 114 patients, 64 cases (56.14%) males, 50 (43.85%) females, aged 56+/-8 years (range 24-96 years).  Bilateral retinal vascular occlusive disorders were seen in only 4 cases (3.5%). Two patients have bilateral CRVO followed by one case of bilateral BRVO and one case of bilateral CRAO.  Out of 114 patients, branch retinal vein occlusion was seen in 62 cases (54.38%), followed by central retinal vein occlusion in 36 cases (31.57%), CRAO in 8 cases (7.01%), and hemi- retinal vein occlusion in 4 cases (3.50%). Hypertension was the most common, (40 cases, 35.08%) risk factor identified for retinal vascular occlusive disorders followed by diabetes 24 cases (21.05%), combined diabetes and hypertension in 22 cases (19.29%), and atherosclerosis in 18 cases (15.78%). Conclusions - Retinal vascular occlusive diseases have systemic as well as ocular risk factors. Understanding of these risk factors is essential for proper treatment of RVOD. Timely identification of risk factors for RVOD may helpful in decreasing ocular and systemic morbidity in these patients.

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