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Leber's hereditary optic neuropathy, a disease which often occurs in young men, causes bilateral loss of central vision. Visual deterioration is progressive, first in one eye, then the other, usually over a period of days to weeks. Recently it was shown that this condition is caused by a mutation of mitochondrial deoxyribonucleic acid (mtDNA). Mitochondria, small structures within the cytoplasm that function in cell metabolism, contain a source of DNA. MtDNA is inherited exclusively from the mother and represents a unique inheritance pattern. For visual loss to occur a substantial percent of mtDNA molecules must be mutant. Sporadic cases of Leber's hereditary optic neuropathy may occur in patients whose maternal ancestors have heteroplasmy (both mutant and normal molecules). It is difficult to explain why all people with predominantly mutant mtDNA molecules do not lose their vision. The importance of heteroplasmy in Leber's patients and the discovery that the proportion of normal and mutant cells can change rapidly underscore the need for mtDNA analysis in order to improve genetic counseling for these patients and their families. (Consumer Summary produced by Reliance Medical Information, Inc.)

Septo-optic dysplasia involves various developmental anomalies affecting the midline of the brain. These anomalies include incomplete development of the optic nerve and possibly pituitary gland insufficiency, and can result in blindness. Depending on the severity of optic nerve abnormality, vision can range from no light perception to nystagmus (involuntary rhythmic eye movements), strabismus (cross-eyed), and, rarely, only a slight reduction in vision, such as 20/30 vision. A review of published reports reveals that approximately two-thirds of patients with septo-optic dysplasia have some type of pituitary insufficiency. In 42 percent of cases describing neurologic status, one or more nonpituitary neurologic deficits was also reported. Seizures, delays in psychomotor development, and mental retardation were the most commonly reported abnormalities. The cases of a brother and sister treated for septo-optic dysplasia are presented. The first patient, a girl, was first seen at 5 months of age because of suspected vision impairment. The pregnancy had been uneventful. Eye examination revealed no response to light. Although initial thyroid function studies were normal, by 23 months of age the child was hypothyroid. She was unable to roll over, but could control her head movements. At 17 months she developed seizures. The brother, born when the sister was 3.5 years old, was suspected of having visual problems at 10 weeks of age. Reaction to light was absent and the diagnosis of septo-optic dysplasia was made. At nine months of age, he developed seizures. Growth hormone abnormality was suspected. The occurrence of this disorder within the same family suggests the possibility of autosomal-recessive inheritance. (Consumer Summary produced by Reliance Medical Information, Inc.)

Leber's hereditary optic neuropathy, which often occurs in young adults, causes bilateral loss of central vision. When this neuropathy occurs in families, it can be traced through the mother's line, which suggests that it is caused by mutation of mitochondrial deoxyribonucleic acid (mtDNA). Mitochondria, small structures within the cytoplasm that function in cell metabolism, contain a source of DNA. This mtDNA mutation has been confirmed in Leber's hereditary optic neuropathy, and provides a simple molecular diagnostic test for this disease. A substantial percent of molecules must be mutant for visual loss to occur. A patient demonstrating visual loss will have ancestors with heteroplasmy (both mutant and normal molecules). Since normal molecules reduce the impact of the mutant ones, identification and quantification of heteroplasmy is important. It was found that the proportion of normal and mutant cells varied greatly, not only between generations, but within different tissues from the same person. To determine the mitochondrial genotype (the particular gene configuration on the chromosome) of a patient or family, more than one family member must be tested and more than one type of tissue must be obtained from the individual being tested. (Consumer Summary produced by Reliance Medical Information, Inc.)

Objective: To investigate the significance of optic nerve head swelling (ONHS) in relation to the pattern of vascular nonperfusion, visual acuity (VA), and demographic profile in retinal venous occlusions (RVOs) occurring within the optic nerve. Methods: Cases of RVO occurring within the optic nerve were divided on the basis of the presence (105 cases) or absence (163 cases) of ONHS. This division was performed by examining the color stereo fundus photographs in conditions masked from other clinical parameters. Duration of symptoms before assessment, age, and sex distributions were compared. The vein involved was identified, and the occlusion was confirmed to have occurred within the optic nerve by observing that the vein pierced the lamina cribrosa as a dilated vein. Fluorescein angiographs were examined, and the extent of vascular nonperfusion in the macula and peripheral retina was quantified from grade 1 to grade 4. The extent of break in the perifoveal capillary arcade was graded as 0, less than or equal to 90 [degrees], and greater than 90 [degrees]. Best-corrected VA was assessed using the Snellen chart. Results: The 2 groups were comparable in terms of the duration of the symptoms before examination. The mean age was significantly younger in the group with ONHS (58.3 vs 65.1 years, P [is less than] .001). Age distribution by sex demonstrated a higher proportion of men younger than 50 years in the ONHS group (19.1% vs 8.6%, P=.01). The group without ONHS involved the papillary vein more frequently (31.3% vs 17.1%, P=.01). The respective proportions of grade 1, 2, 3, and 4 vascular nonperfusion in the macula were 90.5%, 9.5%, 0%, and 0% in the ONHS group, and 62.6%, 14.7%, 13.5%, and 9.2% in the group without ONHS (P [is less than] .001). The corresponding proportions for the peripheral retina were 90.4%, 8.7%, 0%, and 1.0% in the ONHS group, and 62.7%, 13.0%, 18.0%, and 6.2% in the group without ONHS (P [is less than] .001). In 64.6% of cases with ONHS and 42.9% of cases without, the perifoveal arcade was intact. A break greater than 90 [degrees] in the perifoveal arcade was present in 12.5% of cases with and 23.6% of cases without ONHS (P = .004). The median VA was significantly better in the ONHS group (6/24 vs 6/48, P=.005). Conclusions: The RVOs occurring within the optic nerve can be subdivided into 2 distinct groups on the basis of ONHS. The presence of ONHS is associated with younger age, less severe vascular nonperfusion, and better VA. This is consistent with a retrocribrosal site of occlusion, which has access to the pial plexus that can provide collateral channels for retinal venous drainage. Arch Ophthalmol. 2000;118:1357-1363

Several structures can bulge into the sphenoid sinus. These structures include (1) the optic nerve and the internal carotid artery in the superolateral wall, (2) the posterior ethmoid cells in [...]

BECAUSE I FIRST NOTICED THE fuzzy yellow spot in my field of vision in science class, I thought I'd injured my eye by looking at the flash of light from […]

Previous studies have shown that visual stimulation can influence the metabolism of the vision center or visual cortex of the brain. An evaluation of the effect of visual deprivation on the metabolism of glucose in the brain was undertaken. Positron emission tomography (PET) was used to evaluate subjects who were seated in a quiet, dimly lit laboratory. The rate of glucose metabolism in different areas of the brain was studied. Normal volunteers were used in this experiment. The metabolic rates of one group (11 people), who was evaluated with their eyes open, was compared with those of another group (seven people) who kept their eyes closed. Whole brain glucose metabolism was similar in both groups. There was an insignificant difference of decreased glucose metabolism in the calcarine posterior cortex with eye closure. In a second experiment, six patients with poor vision (20/200) due to bilateral optic nerve disease were studied, and compared with a group of 12 normal controls. Whole brain glucose metabolism was similar in both groups. However, in the patients with optic nerve disease, there were significant reductions in glucose metabolism found in several visual centers of the brain: the anterior calcarine cortex, posterior calcarine cortex, peristriate cortex, and lateral occipital cortex. The decreases in glucose metabolism did not correlate with the duration of optic nerve damage experienced by this group of patients. These findings indicate that the level of visual stimulation is not the only factor involved in visual cortex metabolism. This conclusion was reached because closing of the eye resulted in only minimal changes in glucose metabolism, but optic nerve damage was associated with major changes in glucose metabolism in the visual areas of the brain. (Consumer Summary produced by Reliance Medical Information, Inc.)

A common complication of uremia (excessive urea in the blood caused by kidney failure) is nervous system dysfunction; this may occur before, as well as after, hemodialysis treatment (a process of cleaning the blood). Optic neuropathy (nervous system disease) may also result from the same cause of the uremia, the uremic state itself, drug treatment, complications of dialysis, as well as other illnesses. Prompt treatment with dialysis and corticosteroid therapy has been advocated by some. Three patients are presented who developed optic neuropathy while being treated with hemodialysis for uremia. Two of these patients were treated as suggested, with dialysis and concurrent corticosteroid treatment, and no vision improvements occurred. One patient had severe visual distortion, but recovered completely in four weeks after the chelation therapy that followed each hemodialysis treatment was discontinued. The second patient was diagnosed with uremic optic neuropathy, but failed to respond to treatment with hemodialysis and steroids; the pattern of disease was more consistent with idiopathic (of unknown origin) increased cranial pressure. The association of idiopathic intracranial hypertension (high blood pressure) and uremia has been previously reported. The third patient did not respond to dialysis and steroid treatment either and suffered a profound loss of vision. These results support the theory that there are different causes of optic neuropathy in patients who have uremia. This is also consistent with the different central and peripheral nerve pathology seen with uremia. (Consumer Summary produced by Reliance Medical Information, Inc.)

The presence of pallor in enlarged or asymmetric optic disks (where the optic nerve enters the retina) without elevation in intraocular pressure or loss of visual fields, does not constitute glaucoma. The authors identified 48 patients with these optic disk characteristics which resemble those found in glaucoma patients, and have termed the disks glaucoma-like. The patients with glaucoma-like disks were not being treated for glaucoma, nor did they have elevated intraocular pressure or any eye disease, except perhaps early development of cataracts. These patients were compared with a group of 48 patients being treated for open-angle glaucoma (in which the drainage of aqueous humor or fluid in the eye appears to be normal). The glaucoma-like disk patients were younger than the patients diagnosed with glaucoma. In the group of glaucoma-like disk patients 23 percent had a family history of glaucoma; of those who had disk angiograms performed (22 eyes) 75 percent had abnormal results; of the 43 eyes with retinal damage, 59 percent had abnormal angiograms. The glaucoma-like disk eyes showed a higher percentage of nerve fiber layer damage than a normal population, but less than the group of patients with glaucoma. There is a congenital condition called physiologic cup, in which the measurements of the size and depth of the optic disk are greater than normal. The optic disk measurements of the glaucoma-like disks were not statistically different from those of the glaucoma patients. It is concluded that glaucoma-like disks may represent a form of open-angle glaucoma that is at an early stage, before visual field loss has developed. (Consumer Summary produced by Reliance Medical Information, Inc.)

PURPOSE: To report the familial occurrence of optic pits and to screen the candidate PAX2 gene for mutations in this family. METHODS: Clinical family study. Standard mutation analysis of the PAX2 exons. RESULTS: Unilateral optic pits were present in three generations of one family and were inherited in an autosomal dominant fashion. No mutations in the PAX2 gene, responsible for the renal optic coloboma syndrome, were found. CONCLUSION: Unilateral optic pits may be inherited in an autosomal dominant fashion and not in association with mutation in the PAX2 gene.

WHAT'S YOUR DIAGNOSIS? HISTORY Apparently healthy 28-year-old man seen for routine screening physical examination. Reports no visual symptoms, no headaches, and no neurologic symptoms. PHYSICAL EXAMINATION Blood pressure and other [...]