Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Choroiditis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2002

Assessment and classification of choroidal vasculitis in posterior uveitis using indocyanine green angiography.

BACKGROUND: By allowing one to detect fluorescence beyond the retinal pigment epithelium, indocyanine green angiography (ICGA) has made it possible to analyse the choroidal vessels. Our aim was to characterize choroidal vasculitis in posterior uveitis using ICGA. METHODS: Charts of active posterior uveitis patients with a specific diagnosis seen in the different centers participating in the study who had undergone dual fluorescein and ICG angiography were reviewed. The type of inflammatory involvement of the choroidal circulation at entry and the treatment response on follow-up angiograms were analysed. RESULTS: A total of 129 patients were analysed. Choroidal vasculitis could be subdivided into two main patterns: (1) primary inflammatory choriocapillaropathy and (2) stromal inflammatory vasculopathy. The first pattern consisted of hypofluorescent areas up to the late phase of angiography characteristic for choriocapillaris non-perfusion and included entities such as multiple evanescent white dot syndrome (MEWDS), acute posterior multifocal placoid pigment epitheliopathy (APMPPE), multifocal choroiditis (MC), ampiginous choroidopathy and serpiginous choroidopathy. The second pattern consisted of fuzzy indistinct appearance of vessels in the intermediate angiographic phase and diffuse choroidal hyperfluorescence in the late phase indicating inflammatory vasculopathy of larger choroidal vessels. This pattern was found in all cases of active Vogt-Koyanagi-Harada disease, ocular sarcoidosis and tuberculosis and birdshot chorioretinopathy. In Behçet's uveitis of recent onset, choriocapillaris perfusion delay and fuzzy choroidal vessels without diffuse late choroidal hyperfluorescence was found. In posterior scleritis, enlargement of vorticous veins was an additionnal ICGA sign. Stromal inflammatory vasculopathy always responded to anti-inflammatory therapy. A third group of patients with severe retinal or choroidal inflammation presented with associated secondary inflammatory choriocapillaropathy angiographically identical to the primary involvement. CONCLUSIONS: ICGA allowed the hitherto impossible characterization of inflammatory involvement of the choroidal vessels, showing either predominant inflammation of the choriocapillaris or predominant inflammation of the stromal choroidal vessels with or without secondary choriocapillaritis. ICGA will be indispensable for the correct evaluation and follow-up of posterior inflammation with suspected choroidal involvement.

Angiography↗
PubMed2004

[A new approach for studying the retinal and choroidal circulation].

One advantage of advanced computer technology is the high throughput with which the retinal and the choroidal circulation can be evaluated from new aspects. To study the choroidal circulation, we first reevaluated indocyanine green video angiography to improve the visualization of indocyanine green (ICG) images, then applied computer technology to analyze images obtained by an ICG video camera system. We also developed a new instrument to measure oxygen saturation levels in the fundus using spectral retinal imaging technology. I. Choroidal circulation. 1. Reevaluation of ICG video camera system: For this purpose, the bio-chemical nature of ICG was studied. 1) Spectral absorption of ICG: The peak absorption of ICG in distilled water was 780 nm as measured with a spectrophotometer. Its maximum absorption shifted from 780 nm to 805 nm after gradually mixing ICG with human serum protein. Conjugation time of ICG as well as fluorescein sodium with human serum protein was then measured by a stopped flowmeter. It was found that fluorescein sodium conjugated with human serum protein within a few milliseconds, while ICG required more than 600 seconds before equilibrium of the binding was reached. From these observations, we developed a new ICG video system with dual light sources; one, a 780 nm diode laser for the early dye filling phase, and the other, a 805 nm diode laser for the later phase of ICG angiography. 2) Binding properties of ICG in human blood: Blood samples were obtained from three healthy volunteers after intravenous administration of ICG. The resulting plasma samples were fractionated by agarose gel immunoelectrophoresis and polyacrylamide gel DISC electrophoresis. The electrophoretic pattern obtained by each method was observed with an ICG fundus video system. We also studied the affinity of ICG for lipids that are common molecular components of lipoproteins such as high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Four kinds of ICG solutions mixed with phospholipid, free cholesterol, esterified cholesterol, and triacrylglycerol were observed with the ICG fundus video system. Both electrophoretic studies showed that ICG bound intensely to HDL and moderately to LDL, and only the solution with phospholipid fluoresced brightly when observed with the ICG fundus video system. 2. Residual fundus ICG fluorescence: Residual fundus fluorescence observed in the late phase of ICG angiography may be delineated differently in normal subjects and in patients with age-related macular degeneration (ARMD). We performed ICG angiography on 8 normal subjects aged below 36 years (8 eyes), 9 normal subjects aged above 62 years (9 eyes), and 21 patients with ARMD aged 50 to 88 years (37 eyes). The intensity and pattern of fluorescence from angiograms obtained in the ultra-late phase, 24 hours after dye injection, was recorded and analyzed. In the ultra-late phase, 95% of ARMD eyes with choroidal neovascularization (CNV) showed geographic hypofluorescent lesions. These hypofluorescent lesions occurred in 73% of ARMD eyes without CN, while age-matched normal subjects had no hypofluorescent lesions. The mean intensity of fluorescence in the normal elder subject group was significantly higher than that seen in the normal younger subject group. These findings may reflect aging change and bio-distribution of lipid on the Bruch-RPE complex. 3. The early dye filling pattern of the choroid: We performed ICG angiography on 10 healthy young volunteers aged 22 to 26 years (23.4+/-1.3; mean+/-standard deviation) using an improved ICG video camera system. ICG (50 mg) dissolved in 2 ml in distilled water was injected through the antecubital vein. Although the choroidal dye filling varied among subjects, it always began in the macular area. In the 10 subjects, initial dye filling had two patterns: reticular (n=8) and flush (n=2). The choroidal circulation filled completely before the retinal circulation did. Bright fluorescence in the macula and fast blood flow may be correlated with ample blood volume and abundant blood vessels in the macular area. 4. The spreading pattern of ICG fluorescence in the choroid: The ICG images obtained for observing the early dye filling pattern of the choroid were further processed with a computer-assisted image analyzer. Subtracted images were made using the early ICG frames with a time interval of 0.12 second. Ninety frames of time-sequential images for 3 seconds starting from the initial dye appearance in the choroid were prepared to construct an animated image. In the initial phase of eye filling, patchy fluorescence appeared in the fovea. The fluorescence then spread centrifugally in all directions in a wave-like pulsatile manner towards the peripheral fundus with increasing brightness. Thus an animated video of subtracted images allowed us to evaluate flow dynamics at the level of the choriocapillaris. Using this new approach, pathogenic involvement of choroidal circulation in varied chorioretinal diseases such as central serous chorioretinopathy can be studied with precision. II. Retinal circulation. We developed a new device to study the oxygen saturation (OS) levels in a wider fundus area. We call this device a spectral retinal image (SRI) system. We are pursuing the possibility of this instrument being in clinics to evaluate chorioretinal diseases. 1. Introduction of the device: The instrument consists of a Sagnac interferometer that has been mounted on top of a fundus camera, and a software module which consists of an acquisition module and an analysis module. The image acquisition process takes 6 seconds during which the fundus is illuminated by the white incandescent light of the fundus camera at the regular power settings. OS values in each pixel of the fundus image with a 35-degree view can then be estimated from the respective spectrum that is obtained by Fourier-transforming the interferometer signals. Each OS value is represented by a specific color, and each pixel of the fundus image is painted accordingly. 2. Clinical applications. 1) Control study: OS levels of both retinal arteries and veins within a 1 disc diameter (DD) area around the disc were measured from 20 SRIs obtained from 10 healthy volunteers, and were 96.65+/-3.30% and 56.05+/-4.69%, respectively. Then 30 healthy volunteers were recruited for further study in which the OS values were calculated in five retinal regions: (1) juxta-papillary area within 1.75 DD, (2) fovea within 1.0 DD, (3) papillomacular region within 1.0 DD, (4) superior area of the posterior fundus within 1.0 DD, and (5) inferior posterior area of the posterior fundus within 1.0 DD. The OS level of the juxta-papillary area was the highest, while that of the fovea was the lowest and the other three posterior retinal regions were in the middle. Thus OS levels differed at various areas in the retina with statistical significance. In spite of abundant choroidal circulation in the fovea, the overlying retina may have a relative by low oxygen level. As the retinal pigment epithelium may be efficient enough to block the effect of the choroid optically, our results may indicate that the OS levels represent the OS of the retina. 2) Measurement of OS levels in eyes with retinal circulatory disturbances: Eleven eyes of 10 patients with central retinal vein occlusion (CRVO), which showed various degrees of severity, and 4 fellow unaffected eyes of selected patients were examined by both fluorescein angiography (FAG) and the new SRI system. The fluroescein angiograms were correlated with OS maps that were calculated from the SRI. OS grading demonstrated by OS maps correlated well with severity of CRVO, as estimated by FAG. Thus our SRI system is noninvasive with reproducible results, and may prove to be a useful clinical tool to evaluate the degree of retinal ischemia. 3) Measurement of OS levels in eyes with glaucoma: Forty-seven eyes with open angle glaucoma (OAG) of 47 patients and 21 eyes of 21 age-matched normal subjects were recuited for the study. Twelve eyes with low-tension glaucoma (LTG) were included in the OAG eyes and the rest of the OAG eyes had primary OAG. All patients and normal subjects were examined by SRI. Visual field tests for OAG eyes were done with a Humphrey Field Analyzer using the 30-2 program, Swedish interactive threshold argorithm (SITA). OS levels in the retina at 5 different points: superior, inferior, superio- and inferio-temporal, and nasal region within a juxta-papillary area of 200 microm in diameter were calculated from the SRI. OS levels of retinal arteries were also measured and there were no significant differences between OAG and the control group. OAG eyes showed reduced OS levels in the inferio-temporal retina with statistical significance. This observation was more prominent in LTG eyes. The reduced OS levels observed in OAG eyes correlated well with mean deviation (MD) and the sum of total deviation of the 17 points in corresponding areas in the visual field analysis.

Adult↗
PubMed2001

Toxicology of choroid plexus: special reference to metal-induced neurotoxicities.

The chemical stability in the brain underlies normal human thinking, learning, and behavior. Compelling evidence demonstrates a definite capacity of the choroid plexus in sequestering toxic heavy metal and metalloid ions. As the integrity of blood-brain and blood-CSF barriers, both structurally and functionally, is essential to brain chemical stability, the role of the choroid plexus in metal-induced neurotoxicities has become an important, yet under-investigated research area in neurotoxicology. Metals acting on the choroid plexus can be categorized into three major groups. A general choroid plexus toxicant can directly damage the choroid plexus structure such as mercury and cadmium. A selective choroid plexus toxicant may impair specific plexus regulatory pathways that are critical to brain development and function, rather than induce massive pathological alteration. The typical examples in this category include lead-induced alteration in transthyretin production and secretion as well as manganese interaction with iron in the choroid plexus. Furthermore, a sequestered choroid plexus toxicant, such as iron, silver, or gold, may be sequestered by the choroid plexus as an essential CNS defense mechanism. Our current knowledge on the toxicological aspect of choroid plexus research is still incomplete. Thus, the future research needs have been suggested to focus on the role of choroid plexus in early CNS development as affected by metal sequestration in this tissue, to explore how metal accumulation alters the capacity of the choroid plexus in regulation of certain essential elements involved in the etiology of neurodegenerative diseases, and to better understand the blood-CSF barrier as a defense mechanism in overall CNS function.

Animals↗
PubMed1989

An experimental and ultrastructural study on the development of the avian choroid plexus.

The choroid plexus consists of the choroidal epithelium, a derivative of the neural tube, and the choroidal stroma, which originates from the embryonic head mesenchyme. This study deals with epithelio-mesenchymal interactions of these two components leading to the formation of the organ. Grafting experiments of the prospective components have been performed using the quail-chicken marker technique. Prospective choroidal epithelium of quail embryos, forced to interact with mesenchyme of the body wall of chicken embryos, gives rise to a choroid plexus showing normal morphogenesis and differentiation. The choroidal epithelium induces the differentiation of organ-typical fenestrated capillaries, which are highly permeable to intravenously injected horseradish peroxidase. The choroidal epithelium of the grafts constitutes a blood-cerebrospinal fluid barrier. On top of the choroidal epithelium, there are epiplexus cells displaying a typical ultrastructure. The experimental results show that these cells do not originate from the transplanted neural epithelium. Prospective choroidal stroma of chicken embryos does not exert a choroid plexus-inducing influence upon a quail embryo's neural epithelium isolated from parts of the brain that normally do not develop a choroid plexus. The experiments show that the choroidal epithelial cells are determined at least three days before the first organ anlage is detectable.

Animals↗
PubMed2003

Changes in the choroidal circulation of rabbit following RPE removal.

PURPOSE: To examine the effects of surgical removal of the retinal pigment epithelium (RPE) on the choroidal circulation of the rabbit. METHODS: The retina and choroid were examined by biomicroscopy, scanning laser ophthalmoscopy, fluorescein and indocyanine green angiography and histology at various times after the surgical removal of the RPE by gentle aspiration following a prior local vitrectomy and bleb detachment. Comparison was made between small and large areas of RPE removal, or only slight pressure to the retina without removal of RPE. RESULTS: Removal of the RPE layer causes transient leakage of vascular fluid into the subretinal space for at least a week after surgery and loss of perfusion in the underlying choroidal vessels and choriocapillaris at the débridement site. This reduction in local choroidal blood flow can occur within 15 min after RPE débridement and can be transient or permanent. Histology indicates that permanent changes are due to fibroblastic infiltration that compresses the choroidal vessels. Permanent changes tend to occur after removal of relatively large areas of RPE. The removal of small areas of RPE or slight pressure on the retina causes a transient loss of local choroidal perfusion, and fibroblastic infiltration into the choroid does not occur. CONCLUSION: Removal of the RPE causes changes throughout the underlying choroid. It reduces the circulation in the large choroidal vessels as well as the choriocapillaris. If large areas of RPE are removed, this choroidal non-perfusion can be permanent due to fibroblastic infiltration. Small areas of RPE removal or slight pressure on the retina lead to only transient reduction of the choroidal flow. The rapidity with which the choroidal blood flow can be reduced implies a reflex mechanism that responds to sudden RPE pressure and/or trauma. These changes are best observed with ICG angiography.

Angiography↗
PubMed2002

Clinical features of small choroidal melanoma.

The detection and treatment of choroidal melanoma early in its natural course is critical to providing the patient with the best prognosis. Patients with small choroidal melanoma (< 4 mm thickness) develop metastasis in 16% of cases at 5 years follow up, whereas those with medium choroidal melanoma (4-8 mm thickness) and large choroidal melanoma (> 8 mm thickness) develop metastasis in 32 and 53%, respectively. The difficulty with early detection of choroidal melanoma relates to its clinical similarity to benign choroidal nevus. Factors that differentiate small choroidal melanoma from choroidal nevus can be remembered using the mnemonic TFSOM, indicating To Find Small Ocular Melanoma. The letters in this mnemonic represent T (Thickness >2 mm), F (subretinal Fluid), S (Symptoms), O (Orange pigment), and M (Margin touching optic disc). Choroidal melanocytic tumors that display 0 factors have 3% chance for growth at 5 years and most likely represent choroidal nevi. Tumors that display one factor have a 38% chance for growth and those with two or more factors show growth in over 50% of cases at 5 years. Most of those tumors with two or more risk factors probably represent small choroidal melanoma and early treatment is generally indicated. Therefore, ophthalmologists should be aware of the important factors that identify small choroidal melanoma so that early treatment and better life prognosis can be achieved for their patients.

Choroid Neoplasms↗
PubMed1996

Increased nitric oxide synthesis and action preclude choroidal vasoconstriction to hyperoxia in newborn pigs.

We tested the hypothesis that hyperoxia does not cause adequate constriction of choroidal vessels of the newborn (1 to 5 days old) pig, resulting in increased O2 delivery to the retina, possibly due to excess production and/or effects of vasodilators such as nitric oxide (NO). Hyperoxia (100% O2, 45 minutes) led to a decrease in retinal blood flow (RBF) of both newborn and juvenile (5 to 6 weeks old) pigs and also reduced choroidal blood flow (ChBF) in juvenile but not in newborn pigs; the absence of hyperoxia-induced ChBF response in the newborn was associated with a rise in choroidal O2 delivery. Ibuprofen (prostaglandin G/H synthase inhibitor) and 1,3-dimethyl-2-thiourea (a free radical scavenger) did not modify the choroidal hemodynamic responses to hyperoxia in newborn pigs. However, in newborn animals treated with the NO synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME), hyperoxia caused a decrease in blood flow and O2 delivery to the choroid. Consistent with these effects of L-NAME, hyperoxia induced an increase in choroidal cGMP in newborn pigs ventilated with 100% O2 and stimulated nitrite production in isolated choroids exposed to hyperoxia from newborn but not juvenile pigs; these effects were inhibited by NOS blockers. Also, both constitutive and inducible NOS activities were higher in choroidal tissues from newborn than from juvenile animals. In addition, the vasorelaxant effect of the NO donor sodium nitroprusside in vitro was also greater on choroids from newborn than from juvenile pigs. Finally, L-NAME prevented the hyperoxia-induced increase in peroxidation products in the choroid of newborns. It is concluded that hyperoxia does not lead to a decrease in blood flow and O2 delivery to the choroid of the newborn because of increased NO synthesis and effects; since the choroid is the main source of O2 supply to the retina, the present data contribute in providing an explanation for the increased susceptibility of the immature neonate to hyperoxia-induced retinopathy.

Animals↗
PubMed1978

Non-reciprocal contact inhibition of locomotion of chick embryonic choroid fibroblasts by pigmented retina epithelial cells.

Using light and electron microscopy, we have confirmed an earlier observation that chick embryonic pigmented retina epithelial cells (PRE cells) seeded in vitro on cultured sheets of choroid fibroblasts, are able to spread. Spreading is as rapid (and shows the same dependence on lateral contact between PRE cells) as on a serum-coated culture substrate. After 1 h most cells are spreading on the upper surface of the choroid sheet, but after 4 h, some PRE cells can be found sandwiched between overlapping choroid cells, and thus have invaded the sheet. Choroid fibroblasts underlie PRE in vivo, but the ability of PRE cells to spread on cultured fibroblasts is not specific for choroid, since PRE cells spread also on BKH21 hamster kidney fibroblasts, and on fibroblasts from chick embryonic heart. As reported by others for various fibroblastic cells, choroid cells seeded on to choroid sheets or on to cultured PRE are unable to spread. A possible explanation is that spreading of adherent cells is contact-inhibited by the cells in the sheet, just as their leading edges are paralysed on contact, and thus locomotion is inhibited, when fibroblasts collide on a plane substratum. If spreading of seeded cells and cell locomotion are inhibited by the same mechanism, PRE cells should contact-inhibit choroid fibroblasts with which they collide, but not themselves be so inhibited. Using time-lapse cinemicrography, we have found this to be the case. We first established that in homotypic collisions, choroid fibroblasts do show contact inhibition of locomotion, despite the criss-cross (not well monolayered) appearance of confluent cultures. In heterotypic collisions between choroid and PRE we found the predicted nonreciprocal behaviour: the choroid leading edge is paralysed on collision, and the cell subsequently retracts, whereas the active PRE margin appears to be completely unaffected. Speed measurements from a series of such collisions show that the speed of choroid cells is markedly reduced on collision with PRE, whereas the slight slowing of PRE is not statistically significant. We have observed similar behaviour in heterotypic collisions between various epithelial and fibroblastic cells, and so it seems possible that non-reciprocity may prove general for this interaction. If so, it has important implications for the role of contact inhibition of locomotion in phenomena such as morphogenesis, wound healing and the invasiveness of carcinoma cells. On the one hand, non-reciprocal contact-inhibition of locomotion may permit the spreading of epithelia over mesenchymal cells, thus generating or restoring an epithelial bounding membrane. On the other hand, in the absence of other interactions, it would fail to inhibit the invasion of mesenchymal territory by aberrant epithelial cells, or presumably by epithelial free edges.

Animals↗
PubMed2000

Vision-dependent changes in the choroidal thickness of macaque monkeys.

PURPOSE: To determine whether changes in the eye's effective refractive state produce changes in the thickness of the choroid in infant monkeys. METHODS: Normal developmental changes in choroidal thickness were studied in 10 normal rhesus monkeys. Hyperopia or myopia was induced by rearing 26 infant monkeys with either spectacle or diffuser lenses secured in front of one or both eyes. The treatment lenses were worn continuously beginning at approximately 3 weeks of age for an average of 120 days. Refractive status and ocular axial dimensions, including choroidal thickness, were measured by retinoscopy and high-frequency A-scan ultrasonography, respectively. RESULTS: Three lines of evidence indicate that the normal increase in choroidal thickness that occurs during early maturation can be altered by the eye's refractive state. First, in monkeys experiencing form deprivation or those in the process of compensating for imposed optical errors, choroidal thickness and refractive error were significantly correlated with eyes developing myopia having thinner choroids than those developing hyperopia. Second, the choroids in eyes recovering from binocularly induced myopia increased in thickness at a faster rate than the choroids in recovering hyperopic eyes. Third, monkeys recovering from induced anisometropias showed interocular alterations in choroidal thickness that were always in the appropriate direction to compensate for the anisometropia. These changes in choroidal thickness, which were on the order of 50 microm, occurred quickly and preceded significant changes in overall eye size. CONCLUSIONS: Changes in the eye's effective refractive state produce rapid compensating changes in choroidal thickness. Although these choroidal changes are small relative to the eye's refractive error, they may play an important role in the visual regulation of axial growth associated with emmetropization.

Animals↗
PubMedDate not supplied

[Postoperative choroid detachment following microsurgery for rhegmatogenous retinal detachment].

PURPOSE: To evaluate the incidence, predisposing and prognosis factors of post-operative choroidal detachment after microsurgery of rhegmatogenous retinal detachment. MATERIALS AND METHODS: We conducted a retrospective study on a series of 595 consecutive rhegmatogenous retinal detachments referred before any previous failed surgery. Univariate statistical analysis of the data was conducted with evaluation of the odds ratio. RESULTS: Postoperative choroidal detachment developed in 23/595 eyes (3.8%). Significant predictive factors for post operative choroidal detachment included patient's age over 50 years, male gender, pseudophakia, retinal detachment higher than 90 degrees and giant tears. We found no correlation between postoperative choroidal detachment and the retinopexy method, subretinal fluid release and the type of scleral buckling procedure (segmental versus incercling). Postoperative choroidal detachment did not influence at a statistically significant level the postoperative outcome. Permanent retinal reattachment was achieved in 20 of the 23 eyes (87%) with postoperative choroidal detachment, and 564 of 572 eyes (93%) with no post-operative choroidal detachment (p > 0.05). Postoperative PVR occurred in 3 of the 23 eyes (13%) with postoperative choroidal detachment and 3 of the 572 eyes (5%) with no postoperative choroidal detachment (p > 0.05). The postoperative visual outcome was not influenced by the occurrence of postoperative choroidal detachment. CONCLUSION: Postoperative choroidal detachment after retinal detachment microsurgery is a rare complication. Its prognosis is good. The occurrence of postoperative choroidal detachment does not influence the postoperative outcome of retinal detachment microsurgery.

Adult↗
PubMed2001

Microvascular architecture of the rat choroid: corrosion cast study.

This study presents the details of the microvasculature of the rat choroid visualized by scanning electron microscopy of vascular corrosion casts. Wistar Kyoto rats were anesthetized with intraperitoneal sodium pentobarbital. The vascular system was perfused with heparinized saline, and Mercox resin was injected into the cannulated carotid arteries. After polymerization of the resin, the vascular casts were macerated with potassium hydroxide, washed with water, and freeze dried. The casts were examined with a Hitachi S-2360N scanning electron microscope (SEM). Corrosion casts of the entire choroidal vasculature revealed that the two long posterior ciliary arteries supplied the entire uveal vasculature. In the posterior choroid, these arteries formed five to seven branches on each side supplying the adjacent choriocapillaris. No interarterial or arteriovenous anastomoses were seen. The choriocapillaris appeared as a nonhomogeneous and nonlobular monolayer capillary network, consisting of dense honeycomb and irregular patterns. There are two distinct venous systems in the rat choroid. The venous blood from the central region, peripapillary choroid, and sometimes the optic nerve head drain into the posterior ciliary vein. The venous blood from the iris, ciliary body, anterior choroid, and half of the posterior choroid drain into the vortex veins. Corrosion casts and the SEM have shown details of the choroidal vascular architecture. These three-dimensional observations indicate that the rat choroidal vasculature has different features from those of humans and other primates. Despite these interspecies differences, the establishment of a thorough baseline concept of choroidal vasculature should permit additional studies of the choroidal pathology and enable the proper interpretation of results from rat experimental models for extrapolation to humans.

Animals↗
PubMed2002

Temporal relationship of choroidal blood flow and thickness changes during recovery from form deprivation myopia in chicks.

When form deprived, young chicks rapidly develop axial myopia, from which they recover if the treatment is ceased at a sufficiently early age. The increased axial growth of the eye is accompanied by choroidal thinning and decreased choroidal blood flow (ChBF). In contrast, during the early part of the recovery process, the choroid thickens, shifting the retina towards the new plane of focus. Little information is available about ChBF during recovery from myopia. Because of the possibility that choroidal thickening during recovery from myopia might be driven by an increase in ChBF, the temporal relationship of ChBF and choroidal thickness changes was examined during such recovery. White Leghorn chicks were form deprived from 3 days of age for 2-3 weeks using detachable plastic diffusers. Axial ocular dimensions, including choroidal thickness, were then measured by high frequency A-scan ultrasonography at various times after the diffusers were removed up to 240 hr. ChBF was measured transclerally immediately following the A-scan ultrasonography, using laser Doppler flowmetry. In the chicks measured immediately after diffuser removal, the vitreous chamber was 29.9% longer, the choroid was 6.4% thinner and ChBF was 13.7% less in the treated than in the non-treated control eyes. These changes are characteristic of myopic chick eyes and are reversible in young eyes. Thus, in chicks examined 7 hr after diffuser removal, the ChBF in recovering eyes was now greater than that in control eyes. This ChBF increase peaked about 19 hr after the diffusers were removed. The mean increase in ChBF in treated eyes for the 7-30 hr monitoring period was 187%, relative to control eyes. ChBF in the treated eyes gradually returned to the control level after this time. By contrast to the early, transient increase in ChBF, significant choroidal thickening was not observed in treated eyes until 30 hr after diffuser removal, and continued to increase relative to control eyes over the remainder of the monitoring period, reaching a final mean value of 182%. This study demonstrates, in chick eyes recovering from form deprivation myopia, large increases in ChBF that preceded increases in choroidal thickness and were also more transient than the latter. These results raise the possibility that the increase in ChBF may trigger or even drive the subsequent onset of choroidal expansion, perhaps by facilitating the filling of the choroidal lymphatic lacunae that are well developed in the avian eye.

Animals↗
PubMed1995

Differential expression of cell adhesion molecules (CAM), neural CAM and epithelial cadherin in ependymomas and choroid plexus tumors.

A series of frozen specimens of 18 ependymomas and 7 choroid plexus tumors were examined for their expression of cell adhesion molecules, such as neural cell adhesion molecule (NCAM), its polysialylated isoforms (PSA NCAM), and epithelial (E-) cadherin, and of intermediate filament proteins, such as glial fibrillary acidic protein (GFAP) and cytokeratin, using various monoclonal and polyclonal antibodies. Normal choroid plexus and ependyma were taken as controls. Anti-E-cadherin immunoreactivity was observed on the basolateral part of most adult choroid plexus and benign choroid plexus papilloma cells. However, a small number of atypical papillomas and carcinoma cells showed anti- E-cadherin immunoreactivity throughout their cell surface membrane. NCAM were not expressed by adult choroid plexus and benign papilloma cells. Only a few cells expressed NCAM and PSA NCAM in developing choroid plexus, atypical papillomas and carcinomas. Cytokeratin expression was always observed in choroid plexus and their tumors; GFAP expression was variable from case to case. In contrast, ependymal cells and their tumors never expressed E-cadherin but strongly expressed NCAM. PSA NCAM was found in ependymomas exhibiting anaplastic features. All ependymomas strongly expressed GFAP and a few demonstrated slight expression of cytokeratin. These data suggest that, besides GFAP and cytokeratin, NCAM and E-cadherin are of potential diagnostic value in distinguishing choroid plexus tumors from ependymomas. E-cadherin and NCAM may play a role in the functional organization of normal choroid plexus and ependyma, respectively. In particular, incomplete or irregular anti-E-cadherin expression in choroid plexus tumors and PSA NCAM immunoreativity in ependymomas and choroid plexus tumors correlates with the emergence of anaplastic histological features.

Adolescent↗
PubMed1996

Differential distribution of nicotinamide adenine dinucleotide phosphate-diaphorase and neural nitric oxide synthase in the rat choroid plexus. A histochemical and immunocytochemical study.

This study used NADPH diaphorase (NADPHd) histochemistry and neuronal nitric oxide synthase immunocytochemistry to examine the localization of nitric oxide synthase in the choroid plexus of the lateral ventricles and the fourth ventricle of rat brain. That the NADPHd reaction product in choroid plexus was specific to nitric oxide synthase was evaluated: (i) by comparison to immunocytochemical labelling for nitric oxide synthase; and (ii) by comparing NADPHd histochemical staining in choroid plexus and brain (rich in nitric oxide synthase-positive and NADPHd-positive neurons) in the presence or absence of iodonium diphenyl or dichlorophenolindophenol, two potent albeit non-selective inhibitors of nitric oxide synthase activity. In brain, NADPHd histochemistry homogeneously stained neuronal cell bodies, axons and dendrites, while it produced particulate cytoplasmic staining of all epithelial cells in the choroid plexuses of the lateral and fourth ventricles. Within the choroid plexus of the lateral ventricles, NADPHd-positive nerve fibres were also observed around blood vessels and coursing among the epithelial cells. The distribution of immunoreactivity for nitric oxide synthase in brain and in nerve fibres in the choroid plexuses of the lateral ventricles resembled the distribution of histochemical labelling for NADPHd. Choroid plexus epithelial cells were, however, devoid of nitric oxide synthase immunoreactivity. Consistent with this, iodonium diphenyl and dichlorophenolindophenol (0.1 mM) inhibited NADPHd histochemical staining in brain neurons and in choroid plexus nerve fibres, but not in choroid plexus epithelial cells. These results demonstrate that the choroid plexus of the lateral ventricles in rat brain is innervated by nitric oxide synthase-positive nerve fibres. These nitric oxide synthase-positive nerve fibres may have an important role in the regulation of cerebrospinal fluid balance. Although choroid plexus epithelial cells contain an enzyme with NADPHd activity, this enzyme is not nitric oxide synthase.

2,6-Dichloroindophenol↗
PubMed2003

Changing concepts in the management of choroidal melanoma.

PURPOSE: To review emerging information related to changing concepts in the management of choroidal melanoma. DESIGN AND METHODS: This perspective reviews and discusses selected studies from the past two decades that have influenced management strategies for large, medium, and small-size choroidal melanomas. RESULTS: Large choroidal tumors continue to be managed primarily by enucleation. The large tumor trial of the Collaborative Ocular Melanoma Study (COMS) demonstrated neither a positive nor negative effect on 5- and 8-year mortality rates among more than 1000 patients whose eyes containing large choroidal melanomas were randomized to treatment between enucleation alone or enucleation preceded by external radiation. The medium-size tumor trial of the COMS randomized more than 1300 patients between iodine-125 brachytherapy and enucleation. Mortality rates following brachytherapy did not differ from mortality rates following enucleation for up to 12 years after treatment. Iodine-125 has become the most commonly used isotope for brachytherapy in North America. Ten-year follow-up of eyes treated with helium ion and 20 years of experience with proton beam confirm the relative safety and efficacy of these modalities for treatment of choroidal melanoma. Although there is a trend toward earlier treatment of small melanomas, controversy exists regarding the indications for treatment as well as the choice of specific therapy. Recurrences of melanoma after eye-sparing treatment appear to be associated with an increased rate of metastatic disease. Effective adjunctive therapy to prevent or treat melanoma metastasis is lacking. CONCLUSIONS: Choroidal melanoma is a lethal tumor. Although evidence suggests that patients with untreated choroidal melanomas have a poorer prognosis than patients who receive treatment, our current treatments are unable to prevent tumor-related deaths for many patients. The use of preoperative external radiation as an adjunct to enucleation for large choroidal melanomas is unsupported by data from the COMS trial. The use of radiation with either brachytherapy or charged particles for the management of medium-size choroidal melanomas is well supported on the basis of long-term follow-up studies. There is a trend toward treatment of smaller choroidal melanomas. Treatment of melanomas should be directed toward minimizing the potential for recurrences as recurrent melanomas are associated with an increased rate of metastatic disease. Gains in our ability to manage choroidal melanoma will likely be modest at best until effective systemic therapies can be identified.

Choroid Neoplasms↗
PubMed1993

Laser treatment of choroidal neovascularization in patients with angioid streaks.

The benefit of laser photocoagulation to choroidal neovascularization secondary to angioid streaks remains controversial. To further expand our knowledge, we reviewed the records of 20 patients (24 eyes) with classic (well-defined) choroidal neovascularization secondary to angioid streaks, who were treated with laser between 1982 and 1991 at the Retinal Vascular Center of the Wilmer Institute. The choroidal neovascularization was extrafoveal in 18 (75%), juxtafoveal in two, subfoveal in three, and indeterminate in one eye. Seventeen of the 24 fellow eyes (71%) had a disciform scar or choroidal neovascularization, or both. Follow-up ranged from three months to nine years (mean, 3.5 years; median, two years). Lines of visual acuity change averaged -2.5 at three, -2.6 at six, -2.4 at 12, and -4.8 lines at 24 months. Choroidal neovascularization persisted in five of 24 eyes and recurred in nine of the remaining 19 eyes at risk. When the fellow eye had choroidal neovascularization, scar, or both, at the time of treatment, the rate of persistence or recurrence was 65% vs 33% if the fellow eye had no choroidal neovascularization, scar, or both. An average of four lines of visual acuity was lost when fellow eyes had choroidal neovascularization, scar, or both, vs one line when the fellow eye had no choroidal neovascularization or scar. Laser photocoagulation of choroidal neovascularization in patients with angioid streaks can result in closure of the choroidal neovascularization and stabilization of visual acuity.

Adult↗
PubMed2000

Choroidal folds associated with increased intracranial pressure.

PURPOSE: To determine whether a relationship exists between increased intracranial pressure and the presence of idiopathic choroidal folds. METHODS: A prospective study in which 12 consecutive patients presenting with choroidal folds were evaluated by imaging studies (ultrasonography, magnetic resonance imaging, and/or computed tomography) to rule out known causes of choroidal folds, such as orbital disease, choroidal tumor, posterior scleritis, hypotony, and choroidal neovascular membrane. A lumbar puncture was performed on each of these patients, and measurement of opening pressure of cerebrospinal fluid was obtained. RESULTS: Twelve patients with choroidal folds included nine men and three women. Six patients (50%) presented with papilledema in the eye with choroidal folds. The other six patients (50%) presented with only choroidal folds. In this study, 10 (83%) of 12 patients had an opening pressure greater than 230 mm H(2)O. In patients presenting with only choroidal folds, five (83%) of six patients had an opening pressure greater than 230 mm H(2)O, with an average opening pressure of 290 mm H(2)O. CONCLUSION: Depending on the timing of the evaluation, papilledema may or may not be present, and only choroidal folds may be seen as a reflection of increased intracranial pressure. We believe that increased intracranial pressure from any source (that is, pseudotumor cerebri, sinus thrombosis, or intracranial mass) can present with only choroidal folds; therefore, these patients should have an appropriate work-up that should probably include a lumbar puncture before the title of "idiopathic" is given to their finding.

Adult↗
PubMed2004

Visual prognosis in patients with traumatic choroidal rupture.

BACKGROUND: There is a paucity of work in the literature examining the long-term visual prognosis of patients with choroidal ruptures. We performed a study to get a better assessment of long-term visual recovery in these patients as well as to identify prognostic indicators. METHODS: We reviewed the charts of 32 patients who experienced traumatic choroidal rupture following blunt ocular trauma. All charts contained International Classification of Diseases code 363.63 (choroidal rupture). For inclusion in the study, the chart had to contain detailed drawings or photographic evidence that could confirm the presence and location (foveal, juxtafoveal or extrafoveal) of the choroidal rupture. In addition, demographic data and visual acuity on follow-up examinations had to be present. The mechanism and location of the injury, initial and final visual acuity, associated ocular findings and length of follow-up were recorded. RESULTS: Of the 32 eyes 31 had indirect choroidal ruptures and I had a direct rupture. The mean final visual acuity values in the foveal, juxtafoveal and extrafoveal subgroups were 20/68, 20/35 and 20/60 respectively after a mean duration of follow-up of 4.5, 3.5 and 4.4 years respectively. There was no statistically significant difference in mean final visual acuity or mean length of follow-up between the three groups. The eight patients with multiple choroidal ruptures had a mean final vision of 20/31 after a mean follow-up period of 3.8 years. The 24 patients with a single choroidal rupture achieved a mean final vision of 20/47 over a mean duration of follow-up of 4.1 years. There was no difference in final vision or in length of follow-up between the two groups. The six patients under 15 years of age attained a mean final vision of 20/34 over a mean follow-up period of 4.5 years, whereas the adult group achieved a mean final vision of 20/44 over a mean follow-up period of 3.8 years. Again, there was no difference in final vision or in length of follow-up between the two groups. INTERPRETATION: Traumatic choroidal rupture involving the fovea has been thought to have a poor visual prognosis. Our findings show that eyes with foveal choroidal ruptures may regain good central vision over longer follow-up. Furthermore, multiple choroidal ruptures do not necessarily predict a poor visual outcome. Children with choroidal ruptures attained good final visual outcomes.

Adolescent↗