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PubMed2002

Retinal vascular tree morphology: a semi-automatic quantification.

A semi-automatic method to measure and quantify geometrical and topological properties of continuous vascular trees in clinical fundus images is described. Measurements are made from binary images obtained with a previously described segmentation process. The skeletons of the segmented trees are produced by thinning,ff branch and crossing points are identified and segments of the trees are labeled and stored as a chain code. The operator selects a tree to be measured and decides if it is an arterial or venous tree. An automatic process then measures the lengths, areas and angles of the individual segments of the tree. Geometrical data and the connectivity information between branches from continuous retinal vessel trees are tabulated. A number of geometrical properties and topological indexes are derived. Vessel diameters and branching angles are validated against manual measurements and several derived geometrical and topological properties are extracted from red-free fundus images of ten normotensive and ten age- and sex-matched hypertensive subjects and compared with previously reported results.

Adult↗
PubMed1983

Risk factors for retrolental fibroplasia.

Besides oxygen administration and immaturity of the premature retinal vessels, there are other risk factors for retrolental fibroplasia: (1) respiratory distress syndrome; (2) multiple episodes of bradycardia apnoea; (3) exchange transfusions; (4) hyaline membrane disease; (5) anemia of prematurity; (6) hyperbilirubinemia; (7) avitaminosis E; (8) cardiovascular defects; (9) infectious diseases; (10) multiple births; (11) hypocalcemia; (12) hypothermia; (13) hemorrhagic tendency; (14) delayed coaptation of the retina, and (15) spastic diplegia.

Apnea↗
PubMed1999

Reduced retinal vascularization in children with growth hormone deficiency.

The neovascularization in diabetic retinopathy is believed to involve locally produced angiogenic factors. In addition, there are indications that GH may influence retinal vascularization. To investigate the role of GH in retinal vascularization, we examined the retinal vascular pattern in children with congenital GH deficiency. Retinal vessel morphology was evaluated by digital image analysis of ocular fundus photographs in 39 children (5 girls and 34 boys, aged 3.6-18.7 yr) with congenital GH deficiency, and it was compared to that of 100 healthy controls. Twenty children had received GH treatment (0.1 IU/kg daily). All children were born at term, and none of the children had any clinical signs of ocular disease or reduced vision. Children with GH insufficiencies, regardless of whether they were treated with GH, had a significantly lower number of vascular branching points than the reference group (P < 0.0001). Thirty-three percent of the GH-insufficient individuals had a number of vascular branching points less than or equal to the fifth percentile of the reference group. The reduced retinal vascularization observed in children with congenital GH deficiency suggests that GH may be of importance for angiogenesis.

Adolescent↗
PubMed1987

Intraocular involvement of T and B cell lymphomas.

Six elderly patients with ocular involvement by Non-Hodgkin's lymphoma are reviewed. The characteristic clinical features were a history of fluctuating vision, findings of decreased colour vision, constricted visual fields, vitreous cells and subretinal infiltrates. Fluorescein angiography revealed pigment epithelial abnormalities and attenuated retinal vessels. Non-invasive investigations produced a definite diagnosis in two patients and a presumptive diagnosis in a further three. The ocular involvement was confirmed by vitreous cytology in only one patient: vitreous biopsies in three other patients yielded chronic inflammatory cells and no evidence of lymphoma. The condition responded poorly to steroids but well to radiotherapy.

Aged↗
PubMed1990

Optic disc topography and short-term increase in intraocular pressure.

Intraocular pressure is intra- and interindividually inconstant. It is influenced by numerous ocular and general factors. We evaluated the question as to whether a short-term increase in intraocular pressure might change the two-dimensional topography of the optic nerve head. Optic disc photographs of 63 glaucomatous eyes in 33 Caucasian patients and 39 normal eyes in 22 subjects were taken at a baseline intraocular pressure of less than 20 mm Hg and at 1 and 8 s after pressure elevations of 10 and 20 mm Hg. No significant differences in the size and form of the optic disc, optic cup, neuroretinal rim, peripapillary scleral ring or parapapillary chorioretinal atrophy were found. The retinal vessels mostly reacted to the intraocular pressure elevation by an initial decrease and subsequent re-increase in their diameter; this change was significant (P less than 0.05) for the pressure elevation of 20 mm Hg. We conclude that the two-dimensional optic disc topography is not significantly changed by a short-term increase in intraocular pressure.

Adolescent↗
PubMedDate not supplied

Pathogenesis and neuroprotective treatment in Purtscher's retinopathy.

Purtscher's retinopathy is characterized by sudden visual loss in severely traumatized patients and is associated with multiple areas of superficial retinal whitening located primarily in the posterior pole. Visual outcome in Purtscher's retinopathy is variable, and there is no well-defined treatment. We report on a patient with immediate blurred vision in the right eye after a traffic accident. Ophthalmoscopy revealed multiple whitish patches scattered over the macular and peripapillary areas in the right eye. Fluorescein angiography showed multifocal retinal arteriolar occlusion in the early phase and staining of the involved retinal vessels and optic nerve head in the late phase. Indocyanine green angiography (ICG) showed rarefaction of choroidal vessels in the peripapillary area of the right eye at early phase. The late phase ICG study revealed multifocal hypofluorescent patches in the macular and peripapillary areas. Megadose steroid therapy was given with good visual response in the first 2 weeks, and the patient's vision had recovered completely when followed-up 10 months later.

Accidents, Traffic↗
PubMed1998

Prevention of pericyte loss by trolox in diabetic rat retina.

Prolonged hyperglycemia results in a number of diabetic complications, including retinopathy. Pericyte degeneration is one of the earliest histological changes observed in the development of diabetic retinopathy. Increased free radicals generated under hyperglycemia could damage the retina, which abounds in polyunsaturated fatty acids. In the current study, a severalfold increase in thiobarbituric acid-reactive substances was found in rat retina cultured in hyperglycemic medium, which decreased significantly when trolox, an amphipathic antioxidant, was included in the medium. To examine the contribution of oxidative stress in vivo, diabetic rats were fed trolox (0.4% in the diet) during the course of the experiments. After 5 mo of hyperglycemia, whole mounts of retinal vessels were prepared and endothelial cells (E) and pericytes (P) were counted. The ratio of E/P in the retinas obtained from normal rats, diabetic rats, and diabetic rats fed trolox were 1.74 +/- 0.186, 3.78 +/- 0.47, and 2.32 +/- 0.24, respectively. A significant restoration of pericytes by trolox suggests the involvement of oxidative injury during pericyte loss in diabetic retinopathy.

Animals↗
PubMed1995

Permeability of the blood-retinal and blood-aqueous barriers in galactose-fed rats.

Blood-retinal barrier (BRB) and blood-aqueous barrier (BAB) permeability were assessed by various methods to clarify conflicting reports on whether blood-retinal barrier permeability changes occur in diabetic and galactose-fed rats and to assess the potential role of aldose reductase in this process. Different molecular weight probes were utilized in rats fed for 7-11 months either a normal diet or a diet containing 50% galactose with/without the aldose reductase inhibitor AI1576 or Ponalrestat. BRB and BAB were assessed through radiolabelled sucrose permeability studies in eyes where the anterior segment was frozen during dissection compared to eyes where the anterior segments were not frozen and by quantitative autoradiography. In addition, histological studies using Evans Blue dye, microperoxidase and horseradish peroxidase were conducted. In untreated galactose-fed rats a 4-fold increase in the mean permeability surface area product (PA) to sucrose at the BRB was observed when the aqueous humor was not frozen during retinal dissection. However, no increase in the mean PA to sucrose was observed when the aqueous humor of similar eyes was frozen during dissection. Similarly, no retinal vessel permeability increase was observed by either quantitative autoradiography of [3H]-sucrose after 15 minutes of circulation or histological studies with microperoxidase, horseradish peroxidase or Evans Blue dye. Examination of the BAB revealed an increase in the permeability of iris vessels but not the ciliary body in galactose-fed rats which was reduced by treatment with the aldose reductase inhibitor AI1576. These data indicate that while BRB permeability is not increased in galactose-fed rats, BRB permeability measurements with isotopes are subject to possible contamination from the aqueous humor in untreated galactose-fed rats, which can result in false observations of increased BRB permeability.

Aldehyde Reductase↗
PubMed1996

Paediatric and ophthalmologic observations in offspring of alcohol abusing mothers.

The offspring of nine women who had abused alcohol and drugs during pregnancy were studied. Of the 30 children, 10 had fetal alcohol syndrome (FAS) or fetal alcohol effects (FAE). Ophthalmological impairments associated with FAS--impaired vision, optic nerve hypoplasia, cataract, increased tortuosity of retinal vessels--were common. The severity of teratogenic lesions varied among the children and was often related to the level of abuse during pregnancy. Most women were unable to take care of their children during periods of substance abuse. All children with FAS/FAE had learning difficulties. Four mothers abstained from alcohol or drugs during some of their pregnancies and gave birth to children without birth defects.

Adult↗
PubMed1978

Morphology and enzyme activities of the retinal capillaries in mice with the obese-hyperglycaemic syndrome (gene symbol ob).

The retinal capillary bed from 67 obese-hyperglycaemic mice and 64 lean litter mates was isolated by trypsin digestion and investigated with respect to structure and enzyme activities. There was no significant difference in the ratio between numbers of endothelial and mural cells. The capillary walls did not show any obvious structural differences and microaneurysms were not observed. The retinal vessels from the obese-hyperglycaemic mice, however, displayed significantly higher activities of the enzymes hydroxyacyl-CoA-dehydrogenase, asparate aminotransferase (ASAT) and adenylate kinase than their lean litter mates. The activities of glutathione reductase, glucose-6-phosphate dehydrogenase (G-6-PDH) and phosphofructokinase were similar in the two experimental groups. It is suggested that the present data reflect early metabolic disturbances related to diabetic retinopathy.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMedDate not supplied

Nicardipine modification of endothelin-1 effects on visual evoked potential.

Endothelin-1 (ET-1), a vascular endothelium-derived peptide, regulates microcirculation by modulating Ca2+ ion channels. Intravitreally injected ET-1 constricts retinal vessels and reduces blood flow in the optic nerve capillaries. We examined the antagonistic effect of a calcium-ion channel blocker, nicardipine, on ET-1 effects on visual evoked potential (VEP). ET-1 (10(-6); 10 microL) was injected into the posterior vitreous of rabbit eyes. Intravenous nicardipine (20 micrograms/kg) was also given, and VEP was monitored for 2 hours following injection. Thirty minutes after injection, ET-1 had reduced VEP amplitude to 42.6% of the baseline level. The reduction effect continued for the remainder of the study. Nicardipine suppressed the ET-1-induced reduction of VEP amplitude (P < 0.05, Scheffe). The vasospasm produced by ET-1, which reduces the VEP amplitude, involves the CA2+ ion channel. Since nicardipine interferes with the activity of ET-1, we believe that Ca2+ channel blockers can be useful in the treatment of ischemic retinal and optic nerve disorders that are related to abnormal ET-1 production.

Animals↗
PubMed1982

Ophthalmologic abnormalities in the hypereosinophilic syndrome.

Twelve patients with hypereosinophilic syndrome were studied to determine the frequency and type of eye involvement in this systemic disease. Four patients (33%) had visual symptoms, including blurred vision in one or both eyes, and one patient had an episode of complete blindness following cardiac surgery. Five patients (42%) had eye involvement by direct examination, and ten (83%) in fluorescent retinal angiograms. The principal defects noted were occlusions of major retinal vessels, choroidal infarct, and patchy or delayed choroidal filling. As these defects all occurred in patients with other severe systemic complications of the hypereosinophilic syndrome, including cardiologic disease, it is suggested that these lesions were the result of thromboembolic disease and that these patients should receive long-term anticoagulation. It was concluded that eye involvement is a frequent and important feature of the hypereosinophilic syndrome.

Adult↗
PubMed2000

[Lipaemia retinalis due to metabolic syndrome--case report].

BACKGROUND: Lipaemia retinalis is a rarely described ocular manifestation of hyperlipidemia. We report on a female patient with visual loss and visual field defects associated with lipaemia retinalis due to a metabolic syndrome. PATIENT: A 45-year-old female patient presented with bilateral slowly progressing visual loss. Additionally, there were eruptive xanthomatas all over the body. Visual acuity measured 0.2 in both eyes. There was a bilateral creamy discoloration of retinal vessels with a salmon-colored fundus. The peripheral visual field was reduced. Laboratory findings indicated a severe mixed hyperlipidemia (triglyceride 11,694 mg/dl, cholesterol 1724 mg/dl). Immediately initiated therapy to normalize the metabolism resulted in improvement of clinical symptoms. CONCLUSION: Lipaemia retinalis is an useful clinical indicator for triglyceridemia. Persistent lipaemia retinalis may lead to visual loss and visual field defects and may be a sign of severe metabolic disturbances. To prevent cardiovascular complications immediate treatment is necessary.

Biomarkers↗
PubMed1975

Acute macular neuroretinopathy.

An unrecognized acute macular affection occurred in four women, 24 to 35 years old, using oral contraceptives who complained of a sudden decrease of visual acuity or paracentral scotomas. Three patients had bilateral lesions and one patient had unilateral lesions. These lesions consisted of darkish brown-red, wedge-shaped dots in the macula pointing to the fovea. These dots were located mostly on the nasal side to the macula. Biomicroscoby showed these lesions were located in the superficial layers of the retina. The retinal vessels, pigment epithelium, and optic disk showed no distinct pathologic features. Fluorescein angiography, performed repeatedly, showed some questionably dilated perimacular capillaries without leakage in two cases. Static perimetry delineated dense paracentral scotomas. Recovery was slow or absent, confirmed py perimetric observation. Ophthalmoscopic, fluorescein angiography, and perimetric details excluded an affection of the pigment epithelium, the nerve fiber layer, and the optic disk. Since the affection appears to be localized superficially in the retina, we called this specific entity acute macular neuroretinopathy.

Adult↗
PubMed1982

Juvenile xanthogranuloma of the optic nerve, disc, retina, and choroid.

A 20-month-old infant found to have a blind eye with neovascular glaucoma was thought to have a neoplasm of the optic nerve for which enucleation was performed with resection of a long segment of optic nerve. Microscopic examination revealed the enlarged optic nerve and optic papilla to be infiltrated densely by histiocytic cells, including Touton giant cells, all containing large amounts of neutral fat. The histologic picture was indistinguishable from that of juvenile xanthogranuloma. Occlusion of the central retinal vessels had led to hemorrhagic infarction of the retina and neovascular glaucoma. Thorough clinical and laboratory investigations repeated over a period of more than 2 1/2 years failed to disclose any evidence of a systemic disease, and the child has remained in good health. This is believed to be a unique case of juvenile xanthogranuloma of the optic nerve and disc.

Child, Preschool↗
PubMed2006

Endothelial cell proliferation in the choriocapillaris during human retinal differentiation.

BACKGROUND: Differentiation patterns of the neural retina and its retinal vasculature are not well matched. The foveal region differentiates first, however the central retina is not vascularised until late in gestation. The authors explored the hypothesis that higher rates of endothelial cell proliferation in the choriocapillaris of the central retina might compensate for the slow growth of central retinal vessels, providing supplementary nutrients to the region during the early stages of neuronal maturation. METHODS: Frozen sections of five human fetal eyes (14-18.5 weeks' gestation), were examined for Ki-67 and CD34 immunoreactivity using confocal microscopy. Measurements of choriocapillaris area and the number of proliferating choroidal endothelial cells were used to calculate the rate of choroidal endothelial proliferation at five different chorioretinal locations. RESULTS: The choriocapillaris area is consistently greater in the foveal region than at other locations and increases progressively with age. A higher rate of endothelial cell proliferation was found in parts of the choriocapillaris associated with the undifferentiated (proliferating) neural retina, compared with the differentiated, central region. CONCLUSION: The findings suggest that mechanisms regulating proliferation and growth of the choroidal vasculature are independent of differentiation in the neural retina, and are thus profoundly different from mechanisms that regulate formation of the retinal vasculature.

Cell Differentiation↗
PubMed1992

[Eye manifestations of fetal alcohol syndrome].

Alcohol is the most frequent and most important teratogenic agent causing mental and physical retardation in childhood. The alcohol fetal syndrome is characterized by pre- and postnatal growth retardation, hypotonia, hyperactivity, microcephalus, mental retardation and typical craniofacial malformations. The latter includes short palpebral fissures, a poorly developed philtrum, thin upper lip vermillion, short mandibles, a flattened midface structure and dysplastic ears. Ophthalmological signs occur in 90% and include epicanthus, ptosis, myopia, optic nerve hypoplasia and tortuous retinal vessels. Microphthalmus, coloboma and Peters' anomaly have also been described. Five children with alcohol embryopathy are presented. The histopathological findings of the enucleated eye of a 6th child with alcohol embryopathy which was sent to us for examination and which revealed an anterior staphyloma with Peters' anomaly is also described. Ophthalmologists should be aware of alcohol in pregnancy as a preventable cause of eye malformation.

Child, Preschool↗
PubMed1984

Cellular and subcellular events in retinopathy of oxygen toxicity with a preliminary report on the preventive role of vitamin E and gamma-aminobutyric acid: a study in vitro.

Using freshly excised, pure, immature retinal vascular explants from neonatal rabbits as well as vascular cells harvested from such explants in a tissue culture environment, we established the direct cytocidal effect of hyperoxia on the vascular cells. One hundred percent oxygen at one atmosphere induced a marked cellular retraction after 4 to 6 hours of exposure and caused progressive increase in the number and size of lysosomal bodies and autophagic vacuoles. Between 12 to 18 hours, the Golgi apparatus enlarged and focal cytoplasmic degeneration ensued; the various changes in the endoplasmic reticulum, mitochondria, and nucleus became apparent between 18 to 24 hours. After 36 to 48 hours continuous exposure to hyperoxia, the cellular degradation with nuclear pyknosis led to granular and membranous debris. In contrast, the macrophages in the same culture were more resistant to the effect of hyperoxia. Our findings suggest multiple loci for oxygen toxicity in immature retinal vessels and cultured vascular cells. We believe that the cellular retraction is mediated through the prostanoid cascade. The initial event in cytotoxicity of hyperoxia is probably membrane injury, especially of the lysosomal system. The generation of the hydroxyl free radical invokes specific injury to the lysosomes; severe cellular damage occurs due to increased autophagocytosis, probably compounded upon by the inhibition of membrane pumps in the cell and the resulting intracellular acidosis. Injury to cell organelles such as mitochondria, endoplasmic reticulum, and nucleus which occurs at later stages and contributes to the final cell degeneration, may be partly related to the hyperoxic insult. The addition of vitamin E or gamma-aminobutryic acid to the culture medium partially retarded the hyperoxic injury to the vascular cells. In short term experiments, no significant damage occurred with exposure to 30% oxygen. The fact that immature, and not the mature, retinal vascular cells are rapidly and adversely affected by hyperoxia probably entails that the former are deficient in free radical scavenging enzymes but a protective mechanism against oxygen toxicity is acquired with the developmental maturity of these cells.

Animals↗