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Light and electron microscopical studies of monkey retinae after experimental branch vein occlusion by argon laser reveal that the immediate reaction in the corresponding region is one of capillary engorgement and dilatation followed by oedema (intra- and extracellular), and plasma leakage as shown by intravenous injection of horseradish peroxidase. Vascular stasis is characterized by packing of erythrocytes in the capillary lumen, early thrombus formation, and focal haemorrhages. Progressive degenerative changes in the endothelium and pericytes are seen in specimens taken a few hours to a few days after occlusion; within 3 to 4 weeks many vessels in the occluded region are reduced to basement membrane "ghosts" and the lumen and the cellular lodges of some vessels are subsequently invaded by proliferating glia, thus producing permanent capillary closure.

We examined 11 young patients with unilateral ocular findings that included multiple white dots at the level of the retinal pigment epithelium (RPE) or the deep retina, vitreal cells, RPE granularity in the macula, reduced visual acuity, electroretinogram (ERG) and early receptor potential (ERP) amplitudes, and fluorescein leakage from disc capillaries and late staining of the RPE. Recovery of visual function included a dramatic improvement in ERG and ERP amplitudes over several weeks. The etiology of this syndrome remains uncertain; there is no definite evidence of systemic involvement.

Experimental allergic encephalomyelitis (EAE) was produced in 6 adult rhesus monkeys. All the animals developed acute EAE. Optic neuritis developed in all eyes. A vasculo-occlusive retinopathy was seen in five of the 12 eyes. Conjunctivitis and iridocyclitis were seen in some eyes. The available evidence indicates that the retinopathy is secondary to the optic nerve changes and represents central retinal vein occlusion by intraneural compression. Histopathologic studies revealed no evidence of inflammatory infiltration in the retina or around the retinal vessels.

The clinical and histopathologic features of 29 eyes from 29 patients with central retinal vein occlusion (CRVO) are reported. A fresh or a recanalized thrombus was observed in each eye. This study considers the temporal aspects of the cases, and it notes the different morphologic features of the occlusion. These observations explain most of the variability of the changes observed in previous reports. We believe that these different features represent the various stages in the natural evolution of such a thrombus. The interval between CRVO and histopathologic study in our series ranged from six hours to more than 10 years. Local and systemic factors were reviewed and were found to be important in the pathogenesis of thrombus formation. Local diseases with a predisposing effect on CRVO included: glaucoma, papilledema, subdural hemorrhage, optic nerve hemorrhage, and drusen of the optic nerve head. Associated systemic diseases included: hypertension, cardiovascular and cerebrovascular disease, diabetes mellitus, and leukemia with thrombocytopenia. A fresh thrombus in the CRVO was observed in three (10.3%), and a recanalized thrombus in 26 eyes (89.7%). Endothelial-cell proliferation was a conspicuous feature in 14 (48.3%) of the eyes. Chronic inflammation in the area of the thrombus, and/or vein wall or perivenular area was observed in 14 (48.3%) of the eyes. Arterial occlusive disease was observed in seven eyes (24.6%). Cystoid macular edema was found in 26 (89.7%) of the eyes.

A patient with adult-onset diabetes mellitus was referred with a diagnosis of malignant melanoma of the choroid of the left eye. A nonproliferative type of diabetic retinopathy was present, which was studied and documented by stereoscopic fundus photographs and fluorescein angiograms. Following enucleation, the microangiopathies were correlated histologically, using the retinal trypsin digest technique. Four types of microaneurysms were seen histologically that were believed to represent stages in the development of this lesion. Most thin-walled aneurysms tightly packed with erythrocytes did not fluoresce. Aneurysms that were hypercellular and those with thick walls showed early and late fluorescence. Intraretinal microvascular abnormalities were hypercellular dilated channels. Those that take origin from terminal arterioles are believed to represent attempts at neovascularization.

Fifty-two eyes with drusen of the optic nerve head from the autopsy and surgical files of the Eye Pathology Laboratory of the Wilmer Institute from January 1967 through December 1975 were reviewed, and histochemical and electron microscopic studies performed. Histopathologic associations with the drusen included 19 eyes with associated optic nerve atrophy, 16 eyes with peripapillary crowding, one case involving prominent dilated vessels pushed aside by the drusen, and one eye with central retinal vein occlusion. Drusen appear to be composed predominantly of a mucoprotein matrix with significant quantities of acid mucopolysaccharides along with small quantities of ribonucleic acid and, occasionally, iron. The literature is reviewed and various correlations and pathogenetic theories are discussed.

The reported findings of periphlebitis retinae (PR) at autopsy, in which brain autopsy was also performed, in 2 patients with multiple sclerosis (MS) are, so far as the authors are aware, the first histological account of this manifestation of the disease. The similarity between the cellular accumulations around the veins of the central nervous system seen in multiple sclerosis and the periphlebitic cellular accumulations here described suggests that periphlebitis is an initial event in plaque formation.

Occlusions of nine branch retinal veins in eight eyes of seven patients were studied histopathologically by serial sections through the affected areas. Intravitreal neovascularization from the disc, retina, or both was noted in four eyes. Two additional eyes had intraretinal neovascularization (intraretinal microvascular abnormalities). Cystoid macular edema was present in five eyes. A fresh or recanalized thrombus was noted at the site of vein occlusion in all eyes. Inner ischemic atrophy of the retina was found distal to the area of occlusion in six of the nine affected quadrants of the eight eyes. Although the corresponding branch retinal arteries showed varying degrees of sclerosis (severe, three eyes; moderate, five eyes; and minimal, one eye), no definite thrombus was observed in any of them.

The effects of systemic hypertension on the posterior segment of the eye are discussed under the headings of hypertensive choroidopathy, hypertensive retinopathy, and hypertensive optic disc edema. The sympathetic nervous control and autoregulatory mechanisms of the retinal and choroidal vasculatures are briefly reviewed. In hypertensive choroidopathy focal occlusion of choriocapillaris leads to necrosis of retinal pigment epithelium (Elschnig spots). Hypertensive retinopathy is described in vasoconstrictive, exudative, and sclerotic phases, followed by complications of the sclerotic phase. Hypertensive optic disc edema is influenced by the blood supply and extracellular tissue fluid pressure of the optic nervehead. In baboons with hypertensive disc edema, accumulation of axoplasmic components is observed in the optic nervehead.

Eight eyes with central retinal vein occlusion one eye with old central retinal artery occlusion complicated by rubeosis iridis or increased intraocular pressure, or both; and one eye with diabetic retinopathy and rubeosis iridis were treated by retinal panphotocoagulation. Vision did not improve but intraocular pressure was lower and iris neovascularisation regressed in most cases, supporting the hypothesis that retinal hypoxia is a cause of iris neovascularisation and suggesting that retinal panphotocoagulation has a potential prophylactic and therapeutic role in rubeosis iridis and early neovascular glaucoma.

A 59-year-old man developed painless visual loss in his left eye over a one-year period, with rapid progression to blindness over three months. Ocular examination of the left eye revealed proptosis, marked optic disk pallor, dilated retinal veins, and congeries of vessels at the disk margin (opticociliary veins). His right eye was unremarkable. Fluorescein angiography and histopathologic examination confirmed the presence of opticociliary veins communicating between branches of the central retinal vein and the adjacent choroidal vasculature. Primary orbital optic nerve meningioma associated with opticociliary veins was diagnosed.

Clinical findings and fluorescein angiographies of 293 eyes affected with proliferative diabetic retinopathy were reviewed with the specific aim of looking for a possible correlation between rubeosis iridis and the localization of the new vessels in the ocular fundus. In this series there was a highly significant correlation between rubeosis iridis and optic disc new vessels. Rubeosis iridis was present in 49% of the eyes with optic disc new vessels against only 5.5% of the eyes with retinal new vessels not associated with optic disc new vessels. Among the 97 eyes affected with rubeosis iridis, 91 (93.8%) had also optic disc neovascularization. This clinical correlation allows for predicting which of the eyes affected with proliferative diabetic retinopathy are at a high risk of developing rubeosis iridis. In addition to this, this clinical correlation leads to the hypothesis that there is uveal hypoxia associated to retinal hypoxia in those eyes with rubeosis iridis. Thus iris new vessels may result from uveal hypoxia rather than from retinal hypoxia.

I have described the vascular changes after retinal branch vein occlusion and have shown progressive changes both in the large retinal vessels and in the capillary bed. The capillary reactions are comparable to those seen in central retinal vein occlusion. Retinal oedema due to capillary dilatation and leakage occurs in both conditions but, whereas this is generalized in central retinal vein occlusion, local changes occur in branch vein occlusion. Capillary closure also occurs in both conditions, but the neovascular response differs. In branch vein occlusion significant new vessel formation is restricted to the retina leading to recurrent vitreous haemorrhage. This contrasts with central retinal vein occlusion in which thrombotic glaucoma due to predominantly anterior segment neovascularization is the most serious cause of visual loss.

A 40-year-old woman developed profound bilateral loss of vision from chronic atrophic papilledema. There were striking optociliary shunt vessels on the right optic disc. Within 1 month after removal of a massive intracranial meningioma, the shunt vessels had regressed markedly. This regression was evident on fluorescein angiograms. We attribute their resolution to the normalization of intracranial pressure.

A saccular venous macroaneurysm was associated with a chronic ischemic branch retinal-vein obstruction. Only one case of a macroaneurysm involving a vein has been previously reported. Factors contributing to the pathophysiologic features of arterial, venous, and capillary macroaneurysms are also described.

Renal vein thrombosis in early infancy is a complication of dehydration and prolonged hypotension. The onset is usually acute and the most common clinical signs are uni- or bilateral frank masses, hematuria, proteinuria and thrombocytopenia. In most cases, with conservative management, the late outcome is favorable. In the adult, renal vein thrombosis is often a silent complication of the nephrotic syndrome, the hypercoagulability of which may be an important factor in the pathogenesis of the thrombosis. Clinically, the presentation of a sudden complete occlusion is that of severe abdominal and lumbar pain with hematuria and loss of function of the kidney that suffers hemorrhagic infarction. Physical examination often reveals an enlarged kidney. With gradual occlusion, renal function is preserved. The initial diagnostic approach is with ultrasound studies and computed tomography; definitive diagnosis is established by renal venography or by selective renal arteriography. In general, a conservative approach including the use of anticoagulant treatment is preferred to surgical intervention. Priapism is a persistent painful penile erection due to ischemic or non-ischemic causes; therapeutic intracavernosal injection of papaverine is becoming the most common cause. In early and mild stages, aspiration of blood from the corpora cavernosa supplemented with intracavernosal irrigation with alpha-stimulating agents is the procedure of first choice; in late and severe ischemia, a shunt procedure may become necessary. Hepatic vein thrombosis occurs in association with a number of conditions considered predisposing factors including the use of oral contraceptives. The clinical picture may be that of an acute illness with abdominal pain, hepatomegaly, ascites and hepatic failure as well as early death. More often, the onset is insidious with slowly developing ascites and wasting. For the diagnosis, hepatic scintigraphy may be helpful but, at present, ultrasonography, computed tomography and magnetic resonance scanning are procedures of choice. There is, as yet, no adequate treatment. A fatal outcome may be prevented by surgical decompression of the congested liver and, in recent years, liver transplantation has been employed. Portal vein thrombosis, in children, is usually considered a complication of umbilical sepsis or a result of a congenital abnormality of the portal vein. In adults, the most frequent causes are hepatic cirrhosis and neoplasia. Clinically, there may be a sudden appearance of ascites with resolution in a symptom-free interval until the onset of other features of portal hypertension occur. Currently, ultrasound real-time imaging supplemented with Doppler capability, computed tomography and magnetic resonance scanning provide the necessary diagnostic information. Variceal hemorrhage is often the first major complication requiring treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

The outer layers of the normal retina depend on indirect nutrition originating in the choriocapillaris and supplied to the retina by way of the pigment epithelium. An eye with exophytic retinoblastoma is used to demonstrate increased vascularity and tissue substance in the adjacent choroid believed to be indirectly induced by a regional increase in nutritional requirements in the retinal zone of a developing eye.

A case of unilateral central vein occlusion occurring in a normotensive patient with systemic lupus erythematosus (SLE) is reported. This vasculitis is related to SLE. In spite of the observation of circulating immune complex and a positive response to the human basophil degranulation test in the presence of bovine soluble retinal antigen, the real pathogenesis of this unilateral vasculitis remains obscure.

Segmental blood flow, velocity, and vessel diameter were measured in 21 eyes of diabetic individuals with diabetes type 1 and 2. The results for arterial blood flow, velocity, arterial and venous vessel diameter in diabetes show significant differences from the results measured in normal individuals. These flow magnitudes, excluding arterial diameter, significantly depend on the duration time of diabetes. The retinal blood flow magnitudes alter before the marks of diabetic retinopathy are visible. There are differences between the results in diabetes type 1 and type 2 regarding dependence on the duration time of diabetes.

A systematic study of the frequency of retinal vascular abnormalities and cells in the media has been made in 50 patients presenting with acute optic neuritis. Abnormalities were found in 14 (fluorescein leakage in 10, perivenous sheathing in 6, cells in the vitreous in 6 and in the anterior chamber in 4; in 2 the cells in the media were seen without vascular changes). After a mean follow up of 3.5 years multiple sclerosis (MS) had developed in 8/14 patients with vascular abnormalities and/or evidence of inflammation and in 5/32 without; the difference is significant (P less than 0.02). The occurrence of perivenular abnormalities in a region free of myelin and oligodendrocytes provides evidence that the vascular changes in MS can occur independently of contiguous demyelination, and may be the primary event in the formation of a new lesion.

A short synopsis is given on the pathology of the different arterial and venous occlusive diseases in the retina. Based on the author's material and the literature their causes and mechanisms as well as the local sequelae are described, discussed and abondantly illustrated.

A patient with paravenous pigmented chorioretinal atrophy is presented. A differential diagnosis and review of the literature are discussed. Fluorescein angiography confirms the presence of a widespread paravenous retinal pigment epithelial defect with minimally affected choroidal vasculature. The visual fields are constricted in proportion to the extent of the pigmentary abnormality. The electro-oculogram and electroretinogram show reduced responses indicative of a more extensive abnormality than is visible ophthalmoscopically. The etiology and natural course of this entity are unknown.

Spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats received diets differing in amount and source of carbohydrates (CHO). When the CHO was in excess and the source was refined sugar or starch rather than natural ingredients, blood pressure (BP) rose, more so in SHR. This BP increase was observed whether sucrose, glucose, fructose or starch was the principal CHO. Increased urinary excretion of norepinephrine, dopamine and epinephrine also occurred. After only 2-3 months retinal capillary basement membrane damage was demonstrated in SHR and WKY rats ingesting large amounts of sucrose. No similar changes occurred on a high-starch diet. The damage consisted of thickening of capillary basement membranes, loss of homogeneity, and debris inclusions. These results suggest: that high dietary ingestion of CHO in the form of refined CHO augments BP in SHR and WKY rats via increased catecholamine production and/or release, and that the temporally foreshortened experimental period offered by the SHR/WKY model may be valuable in the study of diet-induced retinopathies.

We evaluated retrospectively the cases of 25 patients (26 eyes) with a recent, temporal, branch retinal vein obstruction to determine the relative anatomic position of the obstructed vein in relation to its crossing artery. In 26 (100%) of 26 eyes, the artery lay anterior to the vein, toward the vitreous cavity. A control group was obtained by evaluating the relative anatomic position between the branch retinal artery and vein at an equivalent crossing site along the opposite vascular arcade within the same eye. In the control crossing sites, the artery lay anterior to the vein 65% (15/23) of the time. We conclude that the likelihood that the artery will lie anterior to the obstructed vein at the site of blockage in a branch retinal vein obstruction is substantially greater than what would be expected by chance alone. This anatomic relationship between artery and vein probably plays a role in the cause of a branch retinal vein obstruction and may have therapeutic significance in light of a recent report concerning surgical treatment of such obstructions.

We reviewed the pathology records from January 1965 through July 1975 for aphakic eyes. After exclusion of unsuitable cases, ten eyes (nine patients) with cystoid macular edema and 142 eyes without cystoid macular edema were studied. Clinical ophthalmic records were available for five of the ten eyes with the Irvine-Gass syndrome. Histologic sections were examined, revealing a significant correlation between the Irvine-Gass syndrome and retinal phlebitis, which has not been reported previously, as well as cyclitis and vitritis. Anterior segment operative complications tended to be more prevalent in eyes with the Irvine-Gass syndrome than in those without the Irvine-Gass syndrome, although the assocation was not statistically significant (P less than .1). Retinal trypsin digestion showed the phlebitis to be distributed posteriorly within primary and secondary retinal veins, frequently occurring near points of bifurcation. The changes in permeability seen in the Irvine-Gass syndrome may be due to this retinal phlebitis and to a generalized inflammation-induced increase in capillary permeability. The case of the phlebitis is not known.

Fifteen patients under age 50 years with central retinal vein obstruction (CRVO) and no obvious predisposing ocular or systemic condition underwent a comprehensive medical investigation, including platelet function studies and, in 11 cases, echocardiography. Only 1 patient was found to have a systemic disease (hyperlipoproteinemia), but 11 patients (73%) were found to have abnormalities of platelet function, usually platelet coagulant hyperactivity. Of the 11 patients who underwent echocardiography, 7 (64%) were found to have mitral valve prolapse, a condition predisposing to vascular occlusion, and 4 (60%) of the 7 had abnormalities of platelet function. These findings suggest that mitral valve prolapse contributes to platelet hyperactivity and, ultimately, CRVO.

Ten patients with disc neovascularisation of various aetiologies were studied to ascertain the origin of their new vessels. Fluorescein angiography was carried out with an image intensified video camera. A retinal artery derivation was demonstrated for the first time and was seen in three cases. Six further patients showed a retinal venous supply, and finally there was one from a choroidal source.

Eyes from 47 autopsy cases of multiple sclerosis were studied pathologically. Lymphocytic or granulomatous retinal periphlebitis was found in four cases (seven eyes); focal lymphocytic or granulomatous retinitis was present in three cases (five eyes). These findings were correlated with optic nerve changes (periphlebitis, neuritis, leptomeningitis, and atrophy), retinal venous sclerosis, uveitis, central nervous system involvement, clinical activity of disease at death, and with ultrastructural and immunopathological retinal findings.

Collateral vessel maturation and regional capillary nonperfusion were examined clinically and histopathologically up to 48 months after branch retinal vein occlusion (BVO) in a monkey model. Significant increases in endothelial density, but not pericyte density, were noted in both dilated and normal capillary caliber vessels in regions of collateral flow, independent of duration of BVO from 4 to 15 1/2 months. Patent capillaries in regions of hypoperfusion showed increased endothelial densities but decreased pericyte densities. Pericyte loss was independent of duration of BVO; however, endothelial density may normalize years after BVO in these vessels.

It has been shown that dual trunk central retinal vein (CRV) occurs in 20.3 per cent of a normal population. Confirmatory evidence has been produced by the results of anatomical, histological and micro-dissection studies. Occlusion of the single trunk of such a vein in its retrolaminar, or intraneural part, would result in a venous occlusion affecting one-half of the retina similar to that of branch retinal vein occlusion (BRVO). Yet this should be regarded as a variation of CRVO. Visual prognosis seems to be better in hemi-central retinal venous occlusion than in total CRVO. The site of development of collateral gives a clue to the site of the occlusion. Therefore, it is suggested that hemi-CRVO is a distinct entity and should not be confused with so-called hemi-spherical vein occlusion which is a variation of BRVO.

Eleven infants treated with extracorporeal membrane oxygenator support were examined for ocular complications. Four patients were noted to have retinal and external ocular vascular changes on the left but not on the right. These unilateral findings are believed to be related to right common carotid and internal jugular occlusion. The proposed mechanism involves three factors: cerebral venous congestion, impairment of cerebral and possibly retinal arterial autoregulation, and higher cerebral arterial blood flow on the left compared with the right.

A 74-year-old woman had a saccular dilatation, presumably of the central retinal vein, on the optic nerve head. The lesion caused no symptoms, and over a four-month period showed (vidence of thrombosis and stagnation within it. The lesion caused no interference with either the arterial or venous circulation of the retina. We advised no treatment and continue to observe the patient.