Normal retinal vessels around the first and the second bifurcations were analysed with fundus photographs taken by Zeiss fundus camera. Horizontal disc diameter was set to 10, which was taken as standard units. 1. Distances of the first and the second bifurcations of the retinal vessels from the disc margin were variable; average distance being 10.01 +/- 4.83 (2.0~29.0) and 11.36 +/- 7.99 (1.5~40.0) for the first arterial and venous bifurcations, and 19.47 +/- 8.03 (5.0~42.0) and 22.84 +/- 10.49 (5.0~47.0) for the second arterial and venous bifurcations. 2. Arterial and venous diameters were: 0.56 +/- 0.11 (0.4~1.0) and 0.72 +/- 0.16 (0.5~1.1) at one to two disc diameters from the disc margins, and 0.53 +/- 0.09 (0.4~0.6) and 0.62 +/- 0.14 (0.4~0.9) at three to four disc diameters. 3. Ratio of venous to arterial diameters were 1.285 +/- 0.332 (0.57~2.00) at the first bifurcations and 1.137 +/- 0.266 (0.77~1.77) at the second bifurcations. The ratio was smaller at periphery than at central area. 4. Diameters of arteries became narrower more gradually than those of veins after bifurcations. After the second bifurcations, ratio of the sum of branched vascular diameters to the vascular diameters before bifurcations were 1.617 (0.9~3.0) for artery and 1.454 (0.9~2.8) for vein.
Arteries ; Retinal Vessels ; Veins

The cilio-retinal artery appears on the temporal side of the optic disc margin and is concerned with the supply of the portion between the optic disc and the macula. So, the cilio-retinal artery preserves vision when occlusion of the central retinal artery occurs. The aberrant macular artery is very rare and in most of the cases have been derived from the inferior temporal arterial or venous trunks. When this artery is appeared, the corrected vision is normal but sometimes diminished. The authors have experienced two aberrant retinal vessels of a large cilio-retinal artery and aberrant macular artery combined with the Stargardt's maculopathies. It was reviewed clinically with the literature.
Arteries ; Retinal Artery ; Retinal Vessels* ; Retinaldehyde*

The authors experienoed a case of morning glory syndrome which is an unusual congenital anomaly of optic nerve. The "morning glory" disc of our case was unilaterally enlarged optic disc with a funnel-shaped excavation and an elevated peripapillary tissue annulus. The retinal vessels were straiht andd narrow, and their origins may be obscured by a central mass of whitish tissue overlying the optic disc. Also slit-lamp examination revealed a posterior capsular lens opacity consistent with a Mittendorf's dot. So, we report this case with the review of the literatures.
Cataract ; Optic Nerve ; Retinal Vessels

The retinal blood bessels exit the optic disc and branch in a complex pattern to serve the metabolic need of the inner retina. As the vessels traverse the retina, the arteries and veins frequently cross one another. Recently, there has been renewed iterest in the orientation of the crossing retinal vessels at arteriovenous intersections, particularly as it relates to the risk of branch retinal vein occlusion. The authors studied standard fundus photographs of 30 subjects(60 eyes) who don't habve any retinal and systemic disorders. Arteriovenous crossings were analized for fundus location and relative orientation of the crossing vessels(vein-posterior or vein-anterior). In the superotemporal quadrant, A-V crossings were a greater number, distributed closer to the optic disc than the inferotemporal quadrant. Also a greater proportion of crossings was vein-posterior than the inferotemporal quadrant. These findings may explain the predilection for branch retinal vein occlusions to occur frequency in the superotemporal quadrant.
Arteries ; Retina* ; Retinal Vein Occlusion ; Retinal Vessels ; Retinaldehyde ; Veins

Fundus pictures of normal adult eyes were taken with Zeiss fundus camera under the transiently raised I.O.P. by ophthalmodynamometer. Statistical analysis was as follows: 1) The number of small vessels crossing the optic disc margin was 9.1 +/- 0.28, and was not changed by transiently raised I.O.P. upto 100mmHg. 2) The diameter of the retinal arteriols at optic disc margin didn't show any statistically significant changes by the transiently raised I.O.P. upto 50mmHg.
Adult ; Humans ; Intraocular Pressure* ; Retinal Vessels* ; Retinaldehyde*

Based on analyzing image edge cloning theory and algorithms, a marginal clone algorithm is proposed with a combination of edge connectivity and noise removal algorithm. Simulation results show that the edge image detected by the algorithm has solved problems of traditional edge discontinuities and tsereve noise. Moreover, it has better edge recognition performance.
Algorithms ; Humans ; Image Enhancement ; methods ; Retinal Vessels

No abstract available.
Bartonella Infections* ; Bartonella* ; Retinal Vessels* ; Retinaldehyde*

Accurate segmentation of retinal blood vessels is of great significance for diagnosing, preventing and detecting eye diseases. In recent years, the U-Net network and its various variants have reached advanced level in the field of medical image segmentation. Most of these networks choose to use simple max pooling to down-sample the intermediate feature layer of the image, which is easy to lose part of the information, so this study proposes a simple and effective new down-sampling method Pixel Fusion-pooling (PF-pooling), which can well fuse the adjacent pixel information of the image. The down-sampling method proposed in this study is a lightweight general module that can be effectively integrated into various network architectures based on convolutional operations. The experimental results on the DRIVE and STARE datasets show that the F₁-score index of the U-Net model using PF-pooling on the STARE dataset improved by 1.98%. The accuracy rate is increased by 0.2%, and the sensitivity is increased by 3.88%. And the generalization of the proposed module is verified by replacing different algorithm models. The results show that PF-pooling has achieved performance improvement in both Dense-UNet and Res-UNet models, and has good universality.
Algorithms ; Retinal Vessels ; Image Processing, Computer-Assisted

PURPOSE: To evaluate the effect of panretinal photocoagulation and additive intravitreal bevacizumab injections on central retinal vessel diameters and characteristic retinal vascular caliber changes in diabetic retinopathy. METHODS: Changes in central retinal vessel diameters were retrospectively analyzed before and 6 months after panretinal photocoagulation with or without additive intravitreal bevacizumab injections in 64 eyes first diagnosed with diabetic retinopathy. Vessel diameters and arteriovenous ratio (AVR) were measured using Interactive Vessel Analysis (IVAN) software and the Big six formula. RESULTS: There were significant decreases in central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) in both groups, with and without additive intravitreal bevacizumab injections, 6 months after completion of panretinal photocoagulation (p < 0.001, p = 0.008), but no significant change in AVR (p = 0.338). Additive intravitreal bevacizumab injections did not produce significant changes in central retinal vessel diameters after 6 months compared to vessel diameters treated with panretinal photocoagulation only. Retinal vascular caliber of progressed diabetic retinopathy showed smaller CRAE, larger CRVE, and smaller AVR compared to those of normal or diabetic Korean subjects in a previous study and showed no significant association with age. CONCLUSIONS: CRAE and CRVE decreased significantly 6 months after panretinal photocoagulation in diabetic retinopathy, but additive intravitreal bevacizumab injections did not cause significant additive changes to central retinal vascular calibers in this study. We established the standard retinal vascular caliber of Korean subjects in diabetic retinopathy and analyzed the effects of retinopathy on retinal vessel caliber.
Bevacizumab* ; Diabetic Retinopathy* ; Light Coagulation* ; Retinal Artery ; Retinal Vein ; Retinal Vessels ; Retinaldehyde* ; Retrospective Studies

The author investigated 100 hypertensive patients (199 eyes) on their brachial blood pressure, ophthalmic blood pressure, Fritz's index, sclerotic changes in retinal vessels, and P.S.P. test. The vascular changes of the retina were classified according to the Keith-Wagener scheme, and the sclerotic changes were represented by the point system. For the evaluation of circulatory status of the carotid system, r(s)/r(d)-carotis ratio and cerebrovascular resistance (CVR) were also calculated. The relationships between these data were studied and their results were as follows: (1) There was a linear correlation between mean ophthalmic blood pressure and mean brachial blood pressure, the correlation coefficient being plus 0.83. (2) There was also a linear relationship between fundus changes and mean ophthalmic blood pressure. The more advanced the grade of Keith-Wagener classification and the sclerotic changes, the higher the mean ophthalmic blood pressure. The rise of the mean ophthalmic blood pressure as more marked in K-W grade III, IV, and in grade IV sclerosis. (3) There was a close relationship between P.S.P. test, mean ophthalmic blood pressure and brachial blood pressure. The renal function was disturbed in patients with higher mean ophthalmic blood pressure. (4) The decrease of r(s)/r(d) carotis was always accompanied by the increase of Fritz's index, severity of sclerotic changes in the retina and advancement of the grade of K-W classification. (5) In patients with normal P.S.P. value, there was no single case of advanced sclerosis (more than 10 points of sclerosis). r(s)/r(d) carotis ratio was generally over 1.0. In patients with low P.S.P. value, however, the retinal vascular sclerosis shoshowed more marked changes, and r(s)/r(d) carotis ratio failed below 1.0. (6) Generally, there was a tendency of the increase in the CVR in accordance with the increase in Fritz's index and sclerotic changes. Moreover, functional disturbance of the kidney was usually associated with higher CVR. (7) The author proposed the possibilities that CVR value more than 0.5 or r(s)/r(d)-carotis ratio below 1.0 might represent the advanced sign of vascular sclerosis, disturbance of kidney function.
Blood Pressure ; Classification ; Humans ; Kidney ; Retina ; Retinal Vessels ; Retinaldehyde ; Sclerosis*