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At least 1,189 records · Page 66Linked to original sources
PubMed2000

Significant reduction of the panretinal oxygenation response after 28% supplemental oxygen recovery in experimental ROP.

PURPOSE: To test the hypothesis that after supplemental oxygen recovery (SOR) in the newborn rat model of retinopathy of prematurity (ROP) the preretinal neovascular (NV) incidence and severity are decreased and the panretinal oxygenation ability is improved. METHODS: Newborn rats were first raised in either room air (controls) or variable oxygen (50%/10%) for 14 days. The experimental rats were recovered during the next 6 days (until day 20) in either room air (21% O2) or supplemental oxygen (28%). All groups were then exposed to room air for an additional 6 days (until day 26). On day 20, magnetic resonance imaging (MRI) was used to determine the panretinal oxygenation response (deltaPO2, mm Hg) to a carbogen (95% O2/5% CO2) inhalation challenge. On days 20 and 26, the retinas from a different subset of control, room air-recovered, or SOR-recovered animals were analyzed using ADPase stained or fluorescein-labeled dextran infused retinal flatmounts. RESULTS: On day 20, the panretinal deltaPO2 of the room air-recovered group (125 +/- 5 mm Hg, mean +/- SEM, n = 12) was significantly (P < 0.05) lower than that of the control group (179 +/- 6 mm Hg, n = 11). The panretinal deltaPO2 value for the SOR group (87 +/- 5 mm Hg, n = 7) was significantly (P < 0.05) lower than both the room air-recovered group and the control group. The NV incidence and severity were significantly reduced (P < 0.05) in the SOR animals compared with the room air-recovered animals. In contrast, on day 26 (after 6 days in room air), the NV incidence was statistically (P < 0.05) greater in the animals that had been exposed to SOR compared with room air-recovered animals. CONCLUSIONS: After 28% SOR, the expected decrease in NV incidence and severity occurred but with an unexpected decrease in panretinal oxygenation ability. The present data strongly support an association between subnormal panretinal oxygenation ability and increased NV risk in the newborn rat ROP model. MRI appears to be a powerful new approach for quantitatively and noninvasively measuring retinal oxygenation and may be applicable to study other ischemic or ischemia-related retinopathies in addition to ROP, such as diabetic retinopathy, sickle cell retinopathy, macular degeneration, and glaucoma.

Animals↗
PubMed1996

Partial laser ablation of massive peripapillary subretinal neovascularization.

BACKGROUND: Although peripapillary subretinal neovascular membranes (PSRNs) are less common and often larger than neovascular complexes arising near the fovea, they may lead to severe visual loss. Very large (massive) PSRNs (MPSRNs) are 3.5 disc areas or greater in overall size, are even less common, and may contain a significant occult component, leading to slow and unpredictable growth. Such massive lesions may begin at the nasal margin of the disc and do not become symptomatic until they have extended around the disc toward the macula, threatening central vision. Although complete laser ablation has been used for symptomatic PSRNs with variable success, the optimal treatment of MPSRNs remains controversial. METHODS: The authors reviewed the clinical course of 12 eyes of seven patients with MPSRNs. Ten eyes received laser treatment, which was limited to the temporal portion of the subretinal neovascular complexes only and two received no treatment. RESULTS: Of the ten eyes receiving laser treatment, six showed stabilization of visual acuity, whereas in four the neovascular membrane progressed beneath the fovea with severe visual loss. In the two untreated eyes, the subretinal neovascular membrane progressed beneath the macula with the loss of central vision. CONCLUSIONS: In contrast to the small symptomatic PSRNs, which are usually treated by complete laser ablation, MPSRNs may stabilize with only partial laser treatment. However, both types of lesions may remain stable for long periods of time without any treatment and require treatment only if progression toward the fovea occurs.

Adult↗
PubMed2005

Anti-thyroid methimazole in an acidosis-induced retinopathy rat model of retinopathy of prematurity.

PURPOSE: Methimazole (MMI), an anti-thyroid drug known to reduce serum levels of L-thyroxine (T4) and insulin-like growth factor-1 (IGF-1), has been previously reported to increase the incidence of neovascularization (NV) in an oxygen-induced retinopathy (OIR) model of retinopathy of prematurity (ROP) in rats. We investigated the effect of MMI on the incidence and severity of NV in a non-oxygen-induced model of ROP, acidosis-induced retinopathy (AIR). METHODS: Newborn Sprague Dawley rats were raised in expanded litters of 25 in room air for four or ten days under one of the two following conditions: (1) Our established model of AIR (acidosis via NH4Cl gavage (10 mmol/kg) twice daily from days 2 to 7, followed by two days of recovery) or (2) MMI (given as a 0.1% solution to nursing mothers) in the above AIR model. Left eyes were fixed, and retinas were dissected and ADPase-stained. Flat mounted retinas were graded in a masked manner for presence and severity of NV, and retinal vascular areas were quantified. Serum IGF-1 and T4 concentrations were measured by radioimmunoassay on days 4 and 10. Arterial blood pH measurements were performed on day 4. RESULTS: The incidence and severity of NV were similar between AIR and MMI-AIR rats (incidence: 24% and 33%). Serum IGF-1 concentrations in 10 day MMI-AIR rats were significantly lower than untreated non-acidotic controls (medians: 158 ng/ml and 207 ng/ml; p=0.03). Serum IGF-1 concentrations were similar between 10 day AIR rats and untreated non-acidotic controls (medians: 189 ng/ml and 207 ng/ml; p>0.9). CONCLUSIONS: MMI does not increase the incidence or severity of NV in an AIR neonatal rat model of ROP. Although serum IGF-1 has been considered permissive for NV in immature retinas, supranormal concentrations of serum IGF-1 may not be necessary for abnormal retinal angiogenesis. Further studies are warranted on the roles of serum IGF-1 and L-thyroxine in the pathogenesis of ROP.

Acidosis↗
PubMed1993

Interferon alpha-2a for subfoveal neovascularization in age-related macular degeneration.

BACKGROUND: The current study is a prospective randomized clinical trial to determine the effect of interferon alpha-2a on eyes with subfoveal subretinal neovascularization secondary to age-related macular degeneration (AMD). METHODS: Twenty eyes of 19 patients with subfoveal neovascularization secondary to AMD were prospectively evaluated. Ten eyes were randomized to subcutaneous interferon alpha-2a (3 million units/m2) every other day for 8 weeks, whereas 10 eyes were randomized to observation alone as controls. Fluorescein angiography, best-corrected visual acuity tests, and macular visual field assessments were performed, and all eyes were followed for a minimum of 6 months. RESULTS: At the 2-month follow-up visit, the interferon group manifested somewhat slower neovascular growth than controls, but the results were not statistically significant. At the 6-month follow-up visit, there was no difference in visual acuity, average macular sensitivities, or extent of neovascularization. The rate of neovascular progression was significantly related to the extent of previous macular photocoagulation in both groups. CONCLUSION: Though the rate of neovascular progression was slowed during the second month of interferon treatment, the effect did not persist once interferon was discontinued. No long-term benefit appeared to be present. Unfortunately, lengthening the time of administration, increasing the dosage, or increasing the frequency of administration would likely give rise to unacceptable side effects.

Aged↗
PubMed2005

Pegaptanib sodium for the treatment of neovascular age-related macular degeneration.

This article reviews pegaptanib sodium, a compound developed by Eyetech Pharmaceuticals Inc. and Pfizer Inc., for the treatment of neovascular age-related macular degeneration (AMD). Traditional treatment approaches to neovascular AMD have included destructive therapies such as thermal laser photocoagulation and photodynamic therapy; the use of pegaptanib sodium heralds a new treatment approach that is a non-destructive therapy based on the inhibition of vascular endothelial growth factor activity in the eye. This diminishes the neovascular drive in the pathologically hyperpermeable state of the diseased eye. Pegaptanib sodium is one of the first therapeutics belonging to the class of compounds known as aptamers. The chemistry, mechanism of action, pharmacokinetics and rationale for the clinical use of the drug are reviewed. The article highlights and summarises the results of the multi-centre, randomised, sham-controlled clinical trials with pegaptanib sodium to treat subfoveal choroidal neovascularisation in AMD. In addition, the safety profile is reviewed.

Aptamers, Nucleotide↗
PubMed2004

[Transplantation of iris pigment epithelium].

Transplantation of iris pigment epithelial (IPE) cells to the subretinal space has been attempted as a therapeutic modality for the treatment of age-related macular degeneration (AMD). IPE cells are used because autologous cells are readily available and because IPE and RPE cells share a common embryonic origin, possess the capacity of transdifferentiation into other ocular cells, and share common morphological and functional characteristics. Once the technique of IPE cell transplantation was established in an animal mode, several clinical studies analyzed the behavior of IPE cell suspensions transplanted to the subretinal space of patients with AMD following surgical membrane extraction. In our experience, as well as that of other investigators, transplantation of IPE cells to the subretinal space of AMD patients prevents the recurrence of the subretinal neovascularization and stabilizes but does not improve visual acuity. Since IPE cells transplanted as a cell suspension do not appear to form a cell monolayer in the subretinal space, the transplantation of preformed IPE or RPE cell monolayers is being investigated as the development of an functional cell monolayer is mandatory if functional success, i.e., recovery of vision in AMD patients, is the ultimate goal of IPE cell transplantation.

Aged↗
PubMed1994

Macular subretinal neovascular membrane associated with pseudotumor cerebri.

We report on the development of juxtapapillary subretinal neovascular membrane and permanent severe visual loss in a patient with pseudotumor cerebri. The patient was managed by a lumboperitoneal shunt. After surgery, despite resolving papilledema and intracranial pressure control, the membrane had enlarged rapidly to involve the foveal avascular zone, and resulted in rapid visual loss. The membrane slowly regressed, and was replaced by fibrous tissue at the ninth month, causing permanent severe visual loss.

Adult↗
PubMed1994

Disciform choroidal melanoma.

BACKGROUND: The clinical and histopathologic findings in a hemorrhagic lesion involving the right macula of a 77-year-old man are presented. Clinical and fluorescein angiographic evaluation of the lesion led to a diagnosis of subretinal neovascular membrane secondary to age-related macular degeneration (AMD). The membrane was judged to be amenable to surgical excision and was excised. METHODS: Histopathologic and immunohistochemical studies were performed on the excised tissue. RESULTS: The lesion was a small, epithelioid cell choroidal melanoma. CONCLUSIONS: Newer surgical techniques for AMD may tend to preclude watchful waiting in the diagnosis of unusual hemorrhagic lesions in the macula, thereby increasing the importance of histopathologic examination of any tissue removed during such procedures.

Aged↗
PubMed1997

[Angiogenesis and inhibition of angiogenesis in the eye].

BACKGROUND: Angiogenesis is the formation of new blood vessels from preexisting vessels. Angiogenesis plays an important physiologic and pathologic role in the eye. Pathologic angiogenesis can be found in major causes of human blindness as in diabetic retinopathy and age-related-maculopathy. In recent years great progress has been made in recognizing the mechanisms and regulation of angiogenesis. RESULTS: The general mechanism and the regulation of angiogenesis with proliferative diabetic retinopathy as an example of ocular angiogenesis are reviewed according to recent literature. Angiogenic and antiangiogenic factors regulate the neovascularization. Recent research has identified the vascular endothelial growth factor as the most important mediator of ocular angiogenesis. As well in diabetic retinopathy as in age-related-maculopathy the vascular endothelial growth factor plays a role. New knowledge about ocular angiogenesis is linked to the chance of new antiangiogenic therapies in neovascularizing eye diseases. There exist two ways of ocular antiangiogenic therapy: the first way is to block ocular angiogenic factors such as vascular endothelial growth factor, the other way is to influence the interaction between endothelial cells and extracellular matrix of the newly forming vessels. CONCLUSION: Recent progress in angiogenesis research could result in new causal antiangiogenic drug therapy in ophthalmology. There are some promising animal experiments of local and systemic antiangiogenic therapy. Because of its anatomic localisation the eye is especially suitable for topic antiangiogenic therapy.

Cell Hypoxia↗
PubMed2006

Zone 1 retinopathy of prematurity in a transitional economy: a cautionary note.

PURPOSE: To describe three low risk infants in whom severe retinopathy of prematurity developed. DESIGN: A prospective, observational case series. METHODS: setting: National Hospital of Pediatrics, Hanoi, Vietnam. study population: Premature infants in the neonatal ward. observation procedure: Eye examinations. RESULTS: Severe retinopathy of prematurity occurred in three infants. All had zone 1 disease and other unusually severe findings, such as neovascularization of the disk. These infants would not be at risk for the development of such severe retinopathy of prematurity in countries with a developed economy. CONCLUSIONS: Unusual characteristics of retinopathy of prematurity may be occurring in countries with transitional economies. Screening programs should be implemented and should take into consideration the possibility that retinopathy of prematurity may occur in infants who fall outside the screening guidelines that are used in the developed world.

Developing Countries↗
PubMed1990

Laser treatment of age-related maculopathy (AMD) with subretinal neovascularization (SRN).

Age-related macular degeneration (AMD) is the main cause of visual loss in the Western world. In 80-90% it is the result of the exudative type of AMD with subretinal neovascularization (SRN). As soon as SRN is suspected, fluorescein angiography must be performed without delay. When the neovascular membrane is well-defined, sparing the subfoveolar area--a situation observed in only a small portion of the patients--then green argon or red krypton laser treatment is indicated, the only therapy currently available. The 3-year success rate is about 50% owing to the recurrence of SRN, an as yet unsolved problem. The prognosis also depends on the intensity of the lesions of non-exudative macular degeneration. Statistical evaluation shows that in most patients the main effect of photocoagulation is only to postpone the loss of central vision.

Aged↗
PubMedDate not supplied

Interferon alpha-2a for proliferative diabetic retinopathy after complete laser panretinal photocoagulation treatment.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the effect of interferon alpha-2a, an angiogenesis inhibitor, on eyes with active neovascularization after complete laser panretinal photocoagulation treatment. PATIENTS AND METHODS: Eight patients with active neovascularization persisting for 6 months or more after completion of full panretinal photocoagulation were included in the study. All patients were treated with subcutaneous injections of 6 million international units of interferon alpha-2a, 3 times a week, for an average period of 10 months. Visual acuity, contrast sensitivity, blood tests, fundus photographs, fluorescein angiography, and physical examination were performed periodically. The main outcome measures were visual acuity and extent of neovascularization as assessed by fundus photography and fluorescein angiography. RESULTS: The 5 men and 3 women (mean age, 60 years) had a mean duration of diabetes of 19 years. The average study follow-up was 42.2 +/- 8.7 weeks. Visual acuity and extent of neovascularization improved or remained stable in 7 patients. In none of the patients was there progression of neovascularization, but in 1 patient it could not be assessed due to vitreous hemorrhage. Most patients had malaise during the first weeks of treatment, but none of the patients suffered from nonreversible side effects associated with interferon alpha-2a. CONCLUSION: This pilot study provides evidence that interferon alpha-2a might have a role in the regression of proliferative diabetic retinopathy and that further investigation is warranted.

Adult↗
PubMed1993

Various fundus manifestations in a Japanese family with Best's vitelliform macular dystrophy.

Recently we examined 7 members in one Japanese family with Best's vitelliform macular dystrophy. Five family members in three generations had abnormal electro-oculographic (light peak/dark trough ratio) and normal electroretinographic responses, but their fundus manifestations varied. The proband (a girl) had yellowish macular lesions in both eyes and a neovascular membrane and subretinal hemorrhage in the left macula. The proband's grandfather had mottled macular lesions bilaterally and a mottled extramacular lesion in the left eye. The proband's father had yellowish macular lesions in both eyes and an extramacular lesion in the right eye. The proband's sister had ophthalmoscopically normal fundi. The proband's brother had yellowish macular lesions bilaterally. We believe that finding a variety of fundus manifestations of Best's vitelliform macular dystrophy in one family, as reported in this study, may be uncommon.

Adult↗
PubMed2002

Incidence and severity of neovascularization in oxygen- and metabolic acidosis-induced retinopathy depend on rat source.

PURPOSE: We have previously described oxygen-induced retinopathy (OIR) and metabolic acidosis-induced retinopathy (MAIR) in the neonatal rat, both of which are analogous to human retinopathy of prematurity (ROP). Given that rats of identical strain from two commercial suppliers are phenotypically different, we investigated the incidence and severity of preretinal neovascularization (NV) in rats from different suppliers using the OIR and MAIR models. METHODS: Using our established models for OIR and MAIR, 400 newborn Sprague-Dawley rats, obtained from Harlan Laboratories (HSD) and Charles River Laboratories (CRSD), were raised in 16 expanded litters of 25 (6 OIR and 10 MAIR). Beginning at day 1 of life, OIR litters (3 HSD, 3 CRSD) were exposed to 7 daily cycles of hyperoxia (80% O(2), 20.5 hours) and hypoxia (10% O(2), 0.5 hours) with a gradual return to 80% O(2) over 3 hours. OIR rats were sacrificed after 5 days of room air recovery. MAIR litters (5 HSD, 5 CRSD) were raised in room air and gavaged twice daily with NH(4)Cl (10 mM/kg body weight) from day 2 through day 4. MAIR rats were sacrificed after 3 days of recovery. For both OIR and MAIR litters, retinae from left eyes were dissected, ADPase-stained, and flatmounted. Presence and severity of NV was scored and retinal vascular areas measured by a masked observer. RESULTS: In OIR rats, the incidence of NV was higher in CRSD rats than HSD rats (73% vs. 45%, p = 0.002). NV was more severe in CRSD rats than HSD rats (median clock hours 2 vs. 0, p = 0.0001). In MAIR rats, the incidence of NV was comparable between CRSD and HSD rats (29% vs. 34%, p = 0.53) and there was no significant difference in the severity of NV. CONCLUSIONS: Sprague-Dawley rats obtained from two independent commercial sources differed in their incidence and severity of NV associated with OIR, but not with MAIR. Future genetic studies are warranted to investigate the differences between CRSD and HSD rats, which might yield further clues into the pathogenesis of ROP.

Acid-Base Equilibrium↗
PubMed2007

Optic disc drusen: complications and management.

BACKGROUND: Disc drusen have been found clinically in 0.3% of the population with up to 91% presenting bilaterally. Disc drusen gradually change in their ophthalmoscopic appearance throughout a patient's lifespan. This case highlights the possible ocular complications of disc drusen and the complexity in their treatment because of the risk of visual acuity loss. CASE REPORT: A 43-year-old patient with documented bilateral buried disc drusen presented without symptoms for a routine examination. A subretinal neovascular membrane (SNVM) one quarter of a disc diameter in size with an adjacent subretinal hemorrhage was observed in the right eye with a small subretinal hemorrhage in the fellow eye. The patient was evaluated by a retinologist who deferred photocoagulation of the SNVM considering its nasal disc location. CONCLUSIONS: Diagnosing disc drusen is critical because of the serious pathology they can mimic, including disc edema. Although typically benign, patients with disc drusen should be monitored on a regular basis to rule out ocular complications, which can be potentially sight threatening.

Adult↗
PubMed1990

[Subretinal neovascularization: evolution of cicatrix of photocoagulation in the absence of recurrence].

Eleven patients successfully treated with the argon or krypton laser for macular subretinal neovascularization were followed up in order to determine the extent of long-term enlargement of the chorioretinal scars. The mean follow-up time was 51.5 months and the mean increase in choroidal scar size 46.5%. In 10 patients the scars enlarged more toward the fovea than toward the periphery (51% as opposed to 43%). The rate of enlargement per month decreased with time after treatment. Only one patient exhibited decreased visual acuity during the follow-up period, due to invasion of the foveola by the scar.

Adult↗
PubMedDate not supplied

Surgical removal of subretinal neovascular membranes.

Since 1991 we have been gaining experience in the surgical removal of submacular subretinal membranes in patients with presumed ocular histoplasmosis syndrome (POHS), idiopathic subretinal neovascularisation, myopia and age-related macular degeneration (AMD). Seventeen patients were operated between 1991 and 1993. Significant improvement of vision was achieved in 4 out of 5 patients with POHS, 3 out of 5 with idiopathic neovascularisation, 2 out of 4 with myopia but none of 3 patients with AMD. The results suggest that subretinal neovascularisation can be successfully removed in POHS and in some forms of idiopathic neovascularisation and myopia but probably not in AMD.

Adult↗
PubMed2006

Chlamydia pneumoniae is not detectable in subretinal neovascular membranes in the exudative stage of age-related macular degeneration.

PURPOSE: Age-related macular degeneration (AMD) is the most frequent cause of severe visual impairment in western countries, but its aetiology remains unclear. A growing body of evidence suggests that inflammation contributes to the pathogenesis of AMD, similarly to that shown for atherosclerosis. In view of a number of shared risk factors between the two entities and the hypothesized link between Chlamydia pneumoniae infection and atherosclerosis, we investigated whether C. pneumoniae might be involved in exudative AMD. METHODS: To examine whether C. pneumoniae contributes to the development of subretinal neovascular (SRNV) membranes in AMD, 13 consecutive SRNV membranes surgically excised from patients with exudative AMD were collected and assayed for the presence of C. pneumoniae or other bacterial pathogens by means of polymerase chain reaction (PCR). RESULTS: The age of patients ranged from 68 to 85 years (median 73.5 years). In all 13 SRNV membranes, no DNA of either C. pneumoniae or other pathogens was found by PCR. CONCLUSIONS: These findings indicate that C. pneumoniae is not associated with the development of SRNV membranes in exudative AMD.

Aged↗