The retinal vessel changes are the primary and major features of retinal vascular diseases. The retinal vessel is part of systemic vessels with its own characteristics to sustain normal retinal function. These basic characteristics are important to the correct understanding and proper treatment of retinal vascular diseases. Always keep in mind that the retinal vessels is one part of the systemic vascular system, thus retinal vascular diseases may have systemic etiology, and systemic drug administration may have a profound effects to the whole body. However retinal vascular system also has its own structural and functional characteristics, thus retinal vascular diseases are also different from the systemic diseases. Finally the main function of retinal vascular network is to maintain the neuro-retinal function, thus we should balance the vision protection and treatments against abnormal retinal blood vessels. Over-treatments may damage the retinal vision.
The activities and distributions of succinate dehydrogenase(SDH),malic dehydrogenase(MDH),lactic dehydrogenase(LDH),acid phosphatase(ACP) and alkaline phosphatase(AKP) in retinal vessels were studied and observed with enzymatic histochemical techniques. The retinal vessels showed a b LDH activity, moderate SDH and MDH activity. The dehydrogenase activity described above was evenly and equally distributed in the microvasculature between arterioles and venules, and was the best in arteries. AKP showed predominant activity in the endothelial cells of capillaries and arterioles which were stained bly. No activity for ACP observed in the retinal vessels. The observations above indicate that the retinal vessels are metabolically active and have a great capacity for glycolysis. （Chin J Ocul Fundus Dis,1992,8:6-9）
Retinal blood vessels are the only circulatory system that can be observed under non-invasive conditions. By observing the morphological changes of retinal blood vessels, the changes of blood circulation can be indirectly reflected. The occurrence, development and evolution of different diseases can be discovered. With the development of new detection technologies, especially the wide application of fundus photography and optical coherence tomography, a more intuitive and non-invasive quantitative index is provided for retinal vascular measurement. It is important for the diagnosis, guiding treatment and follow-up of related vascular diseases. This article reviews the development of retinal vessel diameter measurement methods and related applications in clinical diagnosis and treatment.
Objective To investigate the changes of ocular hemodynamics in patients with retinal vein occlussion(RVO)． Methods The hemodynamic parameters(PSV,EDV,PI,Vmax)of central retinal artery(CRA)and central retinal vein(CRV)were measured in the involved eyes(n=48) with RVO and the contralateral clinically healthy eyes(n=39) and in the control eyes(n=40) by color Doppler imaging (CDI)(ATLHDI3000). Results Peak systolic velocity (PSV) and end diastolic velocity (EDV) were significantly lower in the CRA of involved eyes and clinically healthy eyes of patients with RVO compared with control eyes,and pulsatility index(PI)was significantly higher in the CRA of involved eyes of patients with RVO compared with control eyes．PSV were significantly lower in the CRA of involved eyes of patients with RVO compared with their clinically healthy eyes．Pulsatility index(PI)was significantly higher in the CRA of involved eyes of patients with RVO compared with their clinically healthy eyes．Maximun vein velocity (Vmax) was significantly lower in the CRV of involved eyes and clinically healthy eyes of patients with RVO compared with control eyes． Conclusion The changes of hemodynamics in CRA,CRV of involved eyes of patients with RVO may invade their clinically healthy eyes．CDI may be helpful to early diagnosis for RVO． (Chin J Ocul Fundus Dis,1998,14:111-113)
Objective To observe the expression of p53, bcl-2 genes, vascular endothelial cell growth factor（VEGF）, basic fibroblast growth factor（bFGF）, insulin-like growth factor-I （IGF-I）, and the receptors of these factors of retinal vascular endothelial cells (VECs) of 1- to 20-week diabetic rats, and the relationship between the expressions and cell cycle arrest.Methods Retinal sections of diabetic rats induced by alloxan were immunohistochemically stained and observed by light microscopy (LM) and electron microscopy (EM). Dot blotting and Western blotting were used to determine the expression of mRNA, proteins of p53 and bcl-2. Results Under LM, immunohistochemical positive expression of p53 and bcl-2 were found on the vessels of ganglion cell layer and inner nuclear layer of retinae of 8- to 20-week diabetic rats; under EM, these substances were observed depositing in VECs. The retinal VECs also expressed VEGF, bFGF, IGF-I and their receptors. There was no positive expression of other cell types in these retinae, all cell types of retinae in control group, or all cells of retinae of diabetic rats with the course of disease of 1 to 6 weeks. The result of dot blotting revealed that retinal tissue of 20-week diabetic rat expressed p53 and bcl-2 mRNA, and the result of Western blotting revealed that they also expressed p53 and bcl-2 proteins. But retinal tissues of control group did not. Positive expression of bax was not found in the retinae in control group or 1- to 20-week diabetic rats. Conclusion p53, bcl-2 may introduce cell cycle arrest of VECs of retinae in 8- to 20-week diabetic rats. High glucose might stimulate the expression of VEGF, bFGF, IGF-I and their receptors, and the growth factors may keep VECs surviving by self-secretion. (Chin J Ocul Fundus Dis，2003，19：29-33)
Objective To study the proximal diameter changes of retinal blood vessel following branch retinal vein occlusion (BRVO). Methods Color fundus photographs and fundus fluorescein angiography (FFA) photographs of 48 patients with typical unilateral BRVO were analyzed using IMAGEnet software. The diameter of retinal artery (RAD) and vein (RVD) close to optic disc (within one DD from the optic disc) in four quadrants including the affected quadrant were measured with linear measuring tools.Results The proximal diameter of RAD and RVD in corresponding normal quadrants of the BRVO eye had no significant change comparing with the contralateral eye. The proximal diameter of RAD, but not RVD of the affected quadrant such as superotemporal （t=-2.342, P=0.026）or inferotemporal （t=-3.069, P=0.010）quadrant, increased remarkably. Conclusions In corresponding affected quadrant with BRVO, only RAD close to optic disc increases markedly, RVD has no significant change.
Objective To observe the changes of tortuosity and bifurcation angle of retinal arteries and veins in each quadrant of the posterior pole in eyes with high myopia.Methods The tortuosity and bifurcation angle of retinal vessels in each quadrant of the posterior pole in 32 patients (52 eyes) with high myopia and 22 healthy people (30 eyes) were observed and compared. The outcomes were analyzed by multivariate analysis of variance. Results The tortuosity of macular vessels and the artery from optic disc in eyes with high myopia was (1.29plusmn;1.10)times;10-4 and (5.39plusmn;1.93)times;10-5 respectively, and in the normal eyes was (4.15plusmn;2.38) times;10-4 and (9.75plusmn;4.99)times;10-5 respectively; there was significant difference between the two groups （t=1.99, 2.00;Plt;0.05）. The bifurcation angle of superior nasal and inferior nasal retinal arteries in eyes with high myopia was（66.17plusmn;14.04）deg; and (61.20plusmn;11.02) deg; respectively, and in the normal eyes was （77.66plusmn;14.12）deg; and (85.86plusmn;16.45) deg; respectively; there was significant difference between the two groups （F=0.77, 0.83; Plt;0.05）. The bifurcation angle of superior temporal and inferior temporal retinal veins in eyes with high myopia was（92.39plusmn;20.36）deg; and (83.56plusmn;23.50) deg; respectively, and in the normal eyes was （79.45plusmn;15.94）deg; and (70.59plusmn;17.27) deg;; there was significant difference between the two groups （F=2.34, 1.83; Plt;0.05）.Conclusions The vessel tortuosity of retinal arteries and the vessels extending from the optic disc to macula is smaller in eyes with high myopia, while the venous tortuosity has no change. The bifurcation angle of retinal arteries in the superior nasal and inferior nasal field was smaller in eyes with high myopia, while the venous tortuosity has no change. The bifurcation angle of retinal veins in the superior temporal and inferior temporal field was larger in eyes with high myopia.
ObjectiveTo explore the effect of estrogen on the permeability of retinal blood vessel by ovariectomy.MethodsTwenty-two healthy rats were divided into experimental and control group randomly. Estrogen level of rats decreased due to ovariectomy in the experimental group while stabilized by sham-ovariectomy in the control group. The results were confirmed by vaginal epithelium smearing. Retinal vein occlusion was established by photodynamic method, and leakage of Evan's blue in retina was determined by spectrophotometer.ResultsMature value of vaginal epithelium decreased significantly in ovariectomy rats（t=21.008，P=0.000） while not significantly in sham-ovariectomy ones （t=0.319，P=0.756）; the mean leakage of Evans blue was (25.503 0±4.378 47) ng/mg in experimental group, and (17.830 0±4.265 69) ng/mg in the control group, and the difference between the two groups is significant（t=3.969 36，P=0.001）.ConclusionOvariectomy is an useful method to study the effect of estrogen on ocular diseases, and when estrogen level decreases, the permeability of retinal blood vessel increases.(Chin J Ocul Fundus Dis, 2005,21:174-176)
The abnormalities of retinal vessels such as retinal arteriolar narrowing, arteriovenous nicking, micro-aneurysms, retinal hemorrhages, and cotton wool spot are closely related to systemic diseases including hypertension, diabetes mellitus, cardiovascular disorders, stroke and renal diseases. The modern retinal vessels examination technology has features of quick noninvasive, quantitative standardized and intelligent analysis. Taking advantage of these to fully discover the retinal vascular abnormalities and get deeper understanding of the relationship between its' mechanism and systemic vascular diseases is not only helpful to better diagnose and treat retinal vascular diseases, but also contributes to predicting the risk and prognosis of systemic diseases. We suggest emphasizing on the study of correlation between retinal vascular abnormalities and systemic vascular diseases using modern retinal vessels examination technology. It will provide the preventive clue of diseases of circulatory system by finding out the retinopathy. Meanwhile, correctly treating systemic diseases would get a better prognosis of the retinopathy. They exist side by side and play a part together for providing a better prognosis, which would be a new direction for the doctors and scientists in the new era.
ObjectiveTo measure and analyze the oxygen saturation and retinal blood vessel diameter in the eyes of patients with convalescence Vogt-Koyanagi-Harada (VKH) syndrome. MethodsIn this cross-sectional study, 28 eyes of 14 patients with convalescence VKH syndrome (VKH group) and 20 eyes of 10 healthy subjects (control group) were enrolled. The oxygen saturation and retinal blood vessel diameter were detected by spectrophotometric oximetry unit. Retinal images were collected using filters with wavelengths of 570 nm and 600 nm in the darkroom by the same technologist and then the fused image was obtained. The oxygen saturation of retinal vessels was marked in different colors. The measurement was repeated 2-3 times for each patient, then take an average. A top-quality image in each eye was selected to detect the oxygen saturation and diameter of retinal vessel which located in 1.5-3.0 disc diameter from the optic disc. Image analysis and data acquisition were completed by another technologist. ResultsRetinal venous oxygen saturation was (54.34±8.05)% in the VKH group and (60.07±7.91)% in the control group. The former was lower than the latter, the difference was significant (t=2.443, P=0.017). The mean diameter of retinal arteries was (102.8±18.1) μm in the VKH group and (112.9±19.8) μm in the control group. The former was smaller than the latter, the difference was significant (t=2.406, P=0.018). There was no significant difference of the mean diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between two groups (t=-0.330, 0.804, -0.631; P=0.743, 0.403, 0.536). ConclusionsRetinal venous oxygen saturation and the mean diameter of retinal arteries are significantly decreased in patients with VKH syndrome. There is no significant difference of diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between VKH syndrome patients and healthy subjects.