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Results for “Optic Disk”

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At least 19 recordsLinked to original sources
PubMed1977

The histologic basis of optic disk pallor in experimental optic atrophy.

We studied the clinical and microscopic appearances of the optic nerve head in squirrel monkeys with optic nerve degeneration produced by optic nerve transection at the orbital apex. The ophthalmoscopic development of optic disk pallor coincided with the loss of nerve fiber bundles and the rearrangement of the remaining disk astrocytes into dense parallel layers across the nerve head. No astrocytic mitoses were observed and the estimated volume of astrocytes increased only slightly from normal. Among the astrocytes in atrophic disks, many capillaries had patent lumens and ultrastructurally normal endothelial cells. Pallor of the optic disk seems to result from a decrease in the transmission of light into the cytoarchitecture of the atrophic nerve head, not from the absence of capillaries or from extensive astrocytic proliferation.

Animals↗
PubMed1976

Reevaluation of the optic disk vasculature.

The optic disk vessels of owl monkeys and humans were studied in whole mounts injected with silicone rubber and by serial sections of paraffin-embedded tissue. The capillary bed of the optic nerve head in continuous on one side with the retinal vessels and on the other side with the optic nerve behind the globe. The choriocapillaris is a separate capillary bed, even though it and the disk capillaries are both supplied by branches of the posterior ciliary artery. At the junction between choroid and optic disk is a cuff of vessels that seems equivalent to an anterior extension of the pial vessels. This cuff includes capillaries of the central nervous system, was well as arterial branches of the posterior ciliary artery that pass retrograde from the peripapillary choroid and sclera into the pial plexus. While not contradicting previous descriptions of the vascular anatomy in this region, we emphasized that the microvascular bed of the disk is anatomically an integral part of the retina-optic nerve vascular system and deemphasized its relationship to the choroidal vasculature.

Animals↗
PubMed1976

The central vascular pattern of the eyeground in children with drusen of the optic disk.

In a series of 50 children with optic disk drusen the anomaly was found to be associated with unusual properties. A cilioretinal artery was more frequent in the series with drusen than in a control series of the same age. The emergence and course of the central retinal vessels were studied in the right-sided fundi of 46 of the children and in two control series (the fundi of the "better" eyes of 46 strabismic children and the fundi of one of the eyes of 10 children or young adults with papilledema). Analysis of the measurements indicated that early branching of the central vessels and vascular tortuosity are so frequently associated with optic disk drusen that they can be considered features of the anomaly. On the other hand, the fundal vascular features in papilledema seem to be distinguishable by the method used from those associated with optic disk drusen. When the peripapillary choroidal vascular pattern was studied by fluorescein angiography, choriocapillaris filling was delayed in about the half of the angiograms. The aberrant vascular features found on and around optic disks with drusen can be explained by an embryonic affection of the developing vascular system at the optic nerve head. In this respect the anomaly seems to resemble congenital disorders of mesodermal origin.

Adolescent↗
PubMed1976

Congenital anomalies of the optic disk.

Six patients had congenital anomalies of the optic disk: epipapillary fibrous tissue, peripapillary pigmentary disturbance, and anomalies in the size of the optic disk and in the retinal vessels. Congenital anomalies of the optic disk form a spectrum in which many of the ophthalmoscopic features are shared and in which visual function varies.

Adolescent↗
PubMed1976

Glaucomatous cupping of the human optic disk: a neuro-histologic study.

The optic nerve and optic disk in 20 cases of glaucoma were examined neurohistologically. The interruption of retinal axons was found localized in a narrow transversal strip at the level of the posterior part of the lamina cribrosa and immediately behind it. Retinal axons anterior to this zone were mostly intact as long as their ganglion cells of origin were preserved. This picture was essentially identical in cases of primary and secondary glaucoma. The significance of this finding is discussed together with some hypotheses on the origin and causes of the glaucomatous cupping of the optic disk.

Adult↗
PubMed1979

Comparison of photographic techniques and films used in stereophotogrammetry of the optic disk.

We compared photogrammetric measurements of optic cup volume, area, and depth made from two types of stereophotography and two types of film to determine their effect on the precision of the measurements. We found that measurements from simultaneous stereophotography (Donaldson stereoscopic fundus camera) had a smaller range of values and a smaller mean percent error than measurements from consecutive stereophotography (Zeiss Fundus Flash II camera). However, a Student's t-test for related measures showed no significant difference. The measurements from Kodachrome 25 film and Kodak Photomicrography film varied in range and mean percent error without a pattern. The Student's t-test for related measures showed no significant difference.

Evaluation Studies as Topic↗
PubMed1975

Optic disk topography and visual field defects in patients with increased intraocular pressure.

One hundred one eyes of 54 ocular hypertensive patients were studied to determine the value of optic disk evaluation in predicting the presence or absence and the location and type of visual field defects by means of binocular slit-lamp examination and projected 35-mm monocular color slides. We suspected visual field loss erroneously in only one patient, and failed to detect ten (16%) of 61 eyes with field defects. An examiner experienced in slit-lamp evaluation of the optic disk can accurately predict the presence, absence, and location of field defects in most cases by stereoscopic evaluation of disk topography.

Adult↗
PubMed1978

Optic disk neovascularization in hemoglobin SC disease.

A 37-year-old black man had a clinically documented case of optic disk neovascularization associated with hemoglobin SC disease. Through medical evaluation, we ruled out other disorders associated with proliferative retinopathy. Extensive areas of retinal nonperfusion were associated with vasoproliferative retinopathy at the junction of the perfused and nonperfused retina; and a delicate network of neovascularization extended from the optic disk into the vitreous gel in one eye.

Adult↗
PubMed1976

Glaucomatous cupping of the optic disk by ultrasonography.

B-scan ultrasonography was used to evaluate advance glaucomatous cupping of the optic disk (0.7 cup/disk ratio or greater) in one normal subject and six patients with glaucoma. The normal eye emitted a continuous echo from the posterior pole, which conformed to its mild degree of concavity. The glaucomatous eyes emitted echos from the posterior pole, demonstrating the more extreme concavity of the optic cup. Ultrasonographic evaluation of an acrylic plate containing holes of known diameter demonstrated the limits of resolution and artifacts that resulted from this examination.

Glaucoma↗
PubMed1979

Optic disk edema in sarcoidosis.

A 24-year-old woman had bilateral optic disk edema. A granulomatous uveitis and macular edema subsequently ensued. Histologic examination of a biopsy specimen taken from an area of marked hilar adenopathy revealed noncaseating epithelioid cell tubercles. No other associated systemic findings were noted, and after a course of topical and systemic corticosteroid therapy, the ocular manifestations disappeared.

Adult↗
PubMed1978

Drusen of the optic disk and aberrant axoplasmic transport. The XXXIV Edward Jackson memorial lecture.

We believe axoplasmic transport alteration is the anatomic substrate for formation of drusen of the optic disk. In familial cases the cause of axoplasmic transport alteration may be related to the presence of a genetically determined, small, crowded optic nerve head. We believe these congenitally elevated nerve heads evolve over a period of many years through stages of atrophy and drusen formation. Vascular malformations in the familial cases are primarily developmental; however, secondary vascular alterations may occur as the drusen enlarge. In retinitis pigmentosa the drusen may be caused by diminished production of axoplasmic material by the ganglion cell. Chronic alterations in axonal transport from any cause produce aggregates of swollen nerve fibers. These give a yellow-white appearance to the disk tissue and account for the yellow, filled-in appearance of the disk in patients with drusen, chronic atrophic papilledema, melanocytomas, and, in part, for the waxy yellow appearance of the disk in retinitis pigmentosa.

Adult↗
PubMed1976

Optic disk neovascularization associated with chronic uveitis.

Disk neovascularization associated with chronic uvetitis occurred in five patients. The uveitis was most frequently diagnosed as chronic cyclitis, with a marked inflammatory cell response in the vitreous body. Using direct and indirect ophthalmoscopy, slit-lamp biomicroscopy with the Goldmann contact lens, perimetry, and fluorescein angiography and angioscopy, we found no areas of vascular occlusion or nonperfusion. Inflammation probably produced chemical mediators capable of traveling to the optic disk and inducing neovascular proliferation, in the absence of retinal vascular occlusion.

Adolescent↗
PubMed1979

Ocular sarcoidosis occurring as a unilateral optic disk vascular lesion.

A 36-year-old black man who was taking low doses of systemic corticosteroids for systemic sarcoidosis had a vascular lesion of the left optic disk as the only ocular sign. The lesion regressed over a four-month period with high dosage corticosteroid therapy, but he developed optic atrophy and visual acuity of no light perception.

Adult↗
PubMed1992

Changes in optic disk characteristics and number of nerve fibers in experimental glaucoma.

We compared the change in cup/disk ratio and neuroretinal rim area-to-disk area to estimated change in the number of optic nerve fibers in 12 cynomolgus monkeys with unilateral experimental glaucoma. Changes in the cup/disk ratios and neuroretinal rim area-to-disk area were estimated from stereoscopic optic disk photographs that were obtained before and after the development of increased intraocular pressure. Change in the number of optic nerve fibers in the glaucomatous nerves was estimated by comparing them to their fellow normal nerves. A significant linear correlation was present between change in the cup/disk ratios and neuroretinal rim area-to-disk area, and estimated change in the number of optic nerve fibers (r > or = .85; P < .0002). In optic disks with initial cup/disk ratios of 0.2 to 0.3 and neuroretinal rim area-to-disk area of 0.9, an increase in the cup/disk ratio of 0.1 and a decrease of 0.1 in the neuroretinal rim area-to-disk area is associated with a 10% and 9% loss of optic nerve fibers, respectively.

Animals↗