1/31. Bilateral periopticointrascleral hemorrhages associated with traumatic child abuse.PURPOSE: To report a case of bilateral periopticoscleral hemorrhages associated with traumatic child abuse. methods: Postmortem gross examination and histopathologic studies of both eyes and the optic nerves of a 6-month-old infant who died from subdural hematoma. RESULTS: Gross examination and histopathologic step sections disclosed bilateral intrascleral hemorrhages around both optic nerves. In addition, bilateral diffuse multilayered retinal, vitreous, and sublaminar (beneath the internal limiting membrane) hemorrhages were present. CONCLUSION: Periopticointrascleral hemorrhages are characteristic of blunt head trauma and may constitute important forensic evidence in cases of suspected child abuse.- - - - - - - - - - ranking = 1keywords = lamina, membrane (Clic here for more details about this article) |
2/31. Acquired mitochondrial impairment as a cause of optic nerve disease.BACKGROUND: blindness from an optic neuropathy recently occurred as an epidemic affecting 50,000 patients in cuba (CEON) and had clinical features reminiscent of both tobacco-alcohol amblyopia (TAA) and Leber's hereditary optic neuropathy (Leber's; LHON). Selective damage to the papillomacular bundle was characteristic, and many patients also developed a peripheral neuropathy. Identified risk factors included vitamin deficiencies as well as exposure to methanol and cyanide. In all 3 syndromes, there is evidence that singular or combined insults to mitochondrial oxidative phosphorylation are associated with a clinically characteristic optic neuropathy. PURPOSE: First, to test the hypothesis that a common pathophysiologic mechanism involving impairment of mitochondria function and, consequently, axonal transport underlies both genetic optic nerve diseases such as Leber's and acquired toxic and nutritional deficiency optic neuropathies. According to this hypothesis, ATP depletion below a certain threshold leads to a blockage of orthograde axonal transport of mitochondria, which, in turn, leads to total ATP depletion and subsequent cell death. Second, to address several related questions, including (1) How does impaired energy production lead to optic neuropathy, particularly since it seems to relatively spare other metabolically active tissues, such as liver and heart? (2) Within the nervous system, why is the optic nerve, and most particularly the papillomacular bundle, so highly sensitive? Although there have been previous publications on the clinical features of the Cuban epidemic of blindness, the present hypothesis and the subsequent questions have not been previously addressed. methods: patients in cuba with epidemic optic neuropathy were personally evaluated through a comprehensive neuro-ophthalmologic examination. In addition, serum, lymphocytes for dna analysis, cerebrospinal fluid (CSF), sural nerves, and eyes with attached optic nerves were obtained from Cuban patients, as well as from Leber's patients, for study. Finally, we developed an animal model to match the low serum folic acid and high serum formate levels found in the CEON patients, by administering to rats low doses of methanol after several months of a folic acid-deficient diet. Optic nerves and other tissues obtained from these rats were analyzed and compared with those from the Cuban patients. RESULTS: patients from the Cuban epidemic of optic neuropathy with clinical evidence of a selective loss of the papillomacular bundle did much better once their nutritional status was corrected and exposure to toxins ceased. patients with CEON often demonstrated low levels of folic acid and high levels of formate in their blood. Histopathologic studies demonstrated losses of the longest fibers (in the sural nerve) and those of smallest caliber (papillomacular bundle) in the optic nerve, with intra-axonal accumulations just anterior to the lamina cribrosa. Our animal model duplicated the serologic changes (low folic acid, high formate) as well as these histopathologic changes. Furthermore, ultrastructural examination of rat tissues demonstrated mitochondrial changes that further matched those seen on ultrastructural examination of tissues from patients with Leber's. CONCLUSION: mitochondria can be impaired either genetically (as in Leber's) or through acquired insults (such as nutritional or toxic factors). Either may challenge energy production in all cells of the body. While this challenge may be met through certain compensatory mechanisms (such as in the size, shape, or number of the mitochondria), there exists in neurons a threshold which, once passed, leads to catastrophic changes. This threshold may be that point at which mitochondrial derangement leads to such ATP depletion that axonal transport is compromised, and decreased mitochondrial transport results in even further ATP depletion. neurons are singularly dependent on the axonal transport of mitochondria. (- - - - - - - - - - ranking = 0.95455085182742keywords = lamina (Clic here for more details about this article) |
3/31. Idiopathic intracranial hypertension: a case report with optic nerve histopathology.We present the clinical and pathologic findings in an atypical case of idiopathic intracranial hypertension. A 51-year-old man had headaches, visual deterioration, papilloedema, and deafness. neuroimaging was normal, and cerebrospinal fluid pressure monitoring confirmed increased intracranial pressure. The patient was treated with a ventriculo-peritoneal shunt. Histopathology revealed grossly atrophic optic nerves with almost complete axonal loss. The prelaminar portion of the optic nerves was thickened by gliosis and hyalinized capillaries, which have not been described previously.- - - - - - - - - - ranking = 0.95455085182742keywords = lamina (Clic here for more details about this article) |
4/31. Visual outcome of malignant hypertension in young people.A retrospective review was carried out of patients under 16 years old with malignant hypertension, who had been referred to a teaching hospital ophthalmology department because of reduced visual acuity. Four patients (three girls, one boy) were seen between 1994 and 2000 with a mean age at presentation of 11.5 years (range 9-15). In the short term, visual acuity improved after control of blood pressure in all four patients. However, in the long term, two patients were registered blind one to two years after presentation, one because of a choroidal neovascular membrane developing at the macula, and the other because of progressive optic neuropathy. Both of these patients had a longer duration of symptoms before diagnosis, worse visual acuity, and higher blood pressure at presentation when compared with the patients who made a good visual recovery. These observations suggest that early diagnosis of malignant hypertension in children is essential in reducing the likelihood of permanent severe visual damage.- - - - - - - - - - ranking = 0.045449148172579keywords = membrane (Clic here for more details about this article) |
5/31. Neuronal cell death in the visual cortex is a prominent feature of the X-linked recessive mitochondrial deafness-dystonia syndrome caused by mutations in the TIMM8a gene.The Mohr-Tranebjaerg syndrome (MIM 304700) and the Jensen syndrome (MIM 311150) were previously reported as separate X-linked recessive deafness syndromes associated with progressive visual deterioration, dystonia, dementia, and psychiatric abnormalities. In the most extensively studied Norwegian family, the Mohr-Tranebjaerg syndrome was reported to be caused by a one-basepair deletion (151delT) in the deafness/dystonia peptide (DDP) gene at Xq22. This gene has been renamed TIMM8a. We identified a stop mutation (E24X) in the TIMM8a gene segregating with the disease in the original Danish family with the Jensen syndrome, which confirms that the two disorders are allelic conditions. We also report abnormal VEP examinations and neuropathological abnormalities in affected males from the two unrelated families with different mutations. The findings included neuronal cell loss in the optic nerve, retina, striate cortex, basal ganglia, and dorsal roots of the spinal cord. The demonstration of mitochondrial abnormalities in skeletal muscle biopsies in some patients is compatible with the suggestion from recent research that the TIMM8a protein is the human counterpart of an intermembrane mitochondrial transport protein, Tim8p, recently characterized in yeast. The clinical and neuropathological abnormalities associated with mutations in the TIMM8a gene support that this X-linked deafness-dystonia-optic neuropathy syndrome is an example of progressive neurodegeneration due to mutations in a nuclear gene necessary for some, yet unknown mitochondrial transport function. We recommend sequencing the TIMM8a gene, thorough ophthalmological examination, and measuring visual evoked potentials in clinically suspected male patients with either progressive hearing impairment, dystonia, or visual disability in order to establish an early diagnosis and provide appropriate genetic counselling.- - - - - - - - - - ranking = 0.045449148172579keywords = membrane (Clic here for more details about this article) |
6/31. Visual field defect caused by nerve fiber layer damage associated with an internal limiting lamina defect after uneventful epiretinal membrane surgery.PURPOSE: To report a case of visual field defect caused by damage of the nerve fiber layer associated with an internal limiting lamina defect after uneventful epiretinal membrane peeling. DESIGN: Interventional case report. methods: In the right eye, a 43-year-old male patient developed a nasal step and mild inferior arcuate scotoma after uneventful epiretinal membrane surgery without any associated glaucoma. Transmission electron microscopy was performed on the epiretinal membrane specimens. RESULTS: An epiretinal membrane specimen showed adhesion between epiretinal membrane and axons of nerve fiber layer in the area of the internal limiting lamina defect. CONCLUSION: Adhesion between epiretinal membrane and retinal tissue in the area of the internal limiting lamina defect may cause damage of the nerve fiber layer and visual field defect after epiretinal membrane peeling.- - - - - - - - - - ranking = 7.1817965926903keywords = lamina, membrane (Clic here for more details about this article) |
7/31. Perifoveal traction retinal detachment following successful optic disc pit surgery.A 25-year-old male presented 8 years after a successful vitreoretinal operation for a left optic disc pit (ODP). On presentation his visual acuity had reduced from 6/5 (20/15) to 6/12 (20/40) in his operated eye. On examination an annular serous retinal detachment possibly secondary to tangential traction by either the internal limiting membrane (ILM) or residual lamellar vitreous cortex or both around the peripheral macular area was seen. The central fovea was flat. Following an uncomplicated vitrectomy and ILM peel, visual acuity improved to 6/6 (20/20) postoperatively. The author suggests that traction forces are responsible for the development of the serous detachment in eyes with ODP. Epiretinal membranes together with the ILM should be removed in all patients undergoing therapy for a retinal detachment associated with ODP in an effort to initially achieve a further relief of all forces and to try to avoid the late retinal detachment associated with epiretinal membrane or ILM contraction.- - - - - - - - - - ranking = 0.13634744451774keywords = membrane (Clic here for more details about this article) |
8/31. Optic disc traction syndrome associated with central retinal vein occlusion.OBJECTIVE: To describe the association between ischemic central retinal vein occlusion (CRVO) and the development of optic disc (vitreopapillary) traction, as verified by optical coherence tomography (OCT). methods: In a prospective, noncomparative, observational patient series, 3 women aged 51 to 64 years developed an ischemic type of CRVO. One patient underwent cannulation of the central retinal vein with injection of a tissue plasminogen activator. In each eye, the contour of the optic nerve head could not be accurately detected because of overlying fibrous tissue. Each patient underwent OCT examination 6 to 10 months (average, 8.3 months) after the occlusive event. RESULTS: Optic disc traction was found by OCT in the 3 patients. In each, the disc was elevated, associated with either incomplete posterior vitreous detachment (2 eyes) or vitreopapillary fibrous membrane (1 eye). Secondary peripapillary retinal traction and macular or retinal detachment developed ("optic disc traction syndrome"). These findings were less marked, or not evident, on both clinical examination and ocular ultrasonography. CONCLUSIONS: Optic disc traction and secondary localized retinal detachment can develop after ischemic CRVO and may contribute to the poor visual acuity. This syndrome should merit special attention before surgery for CRVO is planned. The use of OCT was helpful to diagnose this syndrome.- - - - - - - - - - ranking = 0.045449148172579keywords = membrane (Clic here for more details about this article) |
9/31. Pars plana vitrectomy and lamina cribrosa puncture in absolute glaucoma.Two patients with refractory end-stage glaucoma who had no light perception underwent pars plana vitrectomy and lamina cribrosa puncture to relieve pain and decrease intraocular pressure. The patients presented with blind, painful eyes and high intraocular pressure (> 40 mm Hg). After the procedure, the pain was relieved and the intraocular pressure was lowered in both cases. The patients remained asymptomatic. Pars plana vitrectomy and lamina cribrosa puncture might be related to the decrease of intraocular pressure, probably by facilitating drainage of aqueous humor through the optic nerve.- - - - - - - - - - ranking = 5.7273051109645keywords = lamina (Clic here for more details about this article) |
10/31. Primary malignant melanoma of the optic nerve simulating a melanocytoma.Primary malignant melanoma of the optic nerve head is an extremely rare tumor. We describe a patient with a pigmented optic nerve lesion that simulated a growing melanocytoma. The pigmented tumor slowly infiltrated the optic nerve causing disc edema, retinal venous congestion, progressive visual field loss, and eventually, loss of central acuity. Following enucleation of the eye, and later resections of the optic nerve to the chiasm, histopathologic examination of the optic nerve, disc, and peripapillary region demonstrated a primary malignant melanoma of the optic nerve without choroidal involvement. Involvement of the optic nerve extended 26 mm beyond the lamina cribrosa. Malignant melanoma of the optic nerve is a real entity and may clinically simulate a melanocytoma.- - - - - - - - - - ranking = 0.95455085182742keywords = lamina (Clic here for more details about this article) |
| | Next -> |