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At least 19 recordsLinked to original sources
PubMed1992

Digital image analysis of optic nerve head pallor as a diagnostic test for early glaucoma.

We developed a computer-based technique to quantify optic nerve head pallor from videographically acquired digitized optic nerve images and tested the ability of pallor measurements to discriminate between normal eyes and eyes with early glaucoma. Corresponding pixel values from images obtained under 540 nm (green) and 640 nm (red) light with a videographic fundus camera were used to quantify optic nerve head pallor. A pallor density histogram was calculated for each eye, and contained values between 0 (red) to 1 (white). A measure of the distribution width of the histogram provided pallor measurements standardized to the measurements of the large veins of the disc. A database of one eye each of 44 normal controls and 70 patients with early open angle glaucoma was used to test the measurements for diagnostic sensitivity and specificity. These standardized pallor measurements did not perform better than absolute pallor measurements to discriminate between normal and glaucomatous eyes. The sensitivity and specificity of standardized pallor measurements (49% and 57%, respectively, for this database) were not as good as those for stereoscopic measurements of disc rim area in the same database (70% and 73%). Pallor measurements of this type do not appear to be sensitive or specific indicators of early glaucoma.

Aged↗
PubMed1992

Quantitative evaluation of optic disc pallor in pseudotumor cerebri patients.

We quantified optic disc pallor in patients with pseudotumor cerebri with the Rodenstock Optic Nerve Head Analyzer before and after optic nerve sheath decompression. Mean frequency distribution of pallor peaked between the pallor values of 0.10 and 0.20 in four pseudotumor cerebri patients and between 0.50 and 0.60 in five normal subjects. The red dominant pallor reflectance in pseudotumor cerebri patients decreased significantly and shifted toward the reflectance of normal subjects gradually during the 9 weeks after successful optic nerve sheath decompression, coinciding with the ophthalmoscopic resolution of papilledema. The computerized pallor measurement with the Rodenstock Optic Nerve Head Analyzer allows an objective and quantitative assessment of papilledema in pseudotumor cerebri patients.

Adult↗
PubMed1992

Neuroretinal rim area measurements by configuration and by pallor in ocular hypertension and glaucoma.

PURPOSE: The purpose of this study is to examine the differences between measurements of neuroretinal rim area of the optic disc defined by configuration and by pallor. METHODS: One hundred seventy-one patients were studied (59 with glaucoma, 96 ocular hypertensive patients, and 16 controls). The magnification-corrected neuroretinal rim area was measured from black-and-white stereoscopic paper prints. The central area of pallor was measured using computer-assisted image analysis techniques. The percentage of central area of pallor was converted into mm2, and an estimate of neuroretinal rim area defined by color was calculated. RESULTS: The correlation between the measurements of neuroretinal rim area by configuration and by pallor was statistically highly significant (r = 0.89, P less than 0.0001). No consistent differences between measurements were found in different diagnostic groups, or in different stages or types of glaucomatous optic disc abnormality. The correlation of changes of both measurements during a 9-year follow-up period also was statistically significant (r = 0.68, P less than 0.001). CONCLUSION: In clinical routine measurements of the neuroretinal rim area, using both configuration and pallor definition does not seem to add to the information.

Adult↗
PubMed1977

Scanning microdensitometry of optic disc pallor in glaucoma.

A scanning microdensitometric technique has been developed for measuring the optical density of black and white photographs of the optic disc. From the frequency distribution curve of all the densities of the whole area of the optic disc, a separate peak was identified as corresponding to the area of pallor of the optic disc. Areas of pallor were measured as percentage of areas of the total disc for normal, ocular hypertensive, open-angle glaucoma patients, and those with suspect discs. Median values of percent area of pallor showed correspondence with the clinical diagnosis, the glaucoma patients having significantly larger areas than the normal subjects. The microdensitometric technique provides an objective means of measuring the amount of optic dis pallor. It has potential usefulness for screening and for following up suspect and confirmed glaucomas to determine progression of the disease.

Densitometry↗
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↗
PubMed1979

The mechanism of disc pallor in experimental optic atrophy. A fluorescein angiographic study.

Ascending optic atrophy was produced in 13 eyes of owl monkeys (Aotestrivirgatus) by retinal photocoagulation. Color fundus photography and fluorescein angiography were used to study and document the evolution of nerve head abnormalities. The optic nerve heads were also studied histopathologically. Except in certain instances of early transient (relative) filling defects, normal disc fluorescent patterns were preserved, despite clinically apparent optic nerve head pallor. Sectorial defects did not persist into the later phases of the angiogram. These findings may suggest a reduced blood flow, but neither angiographic nor histopathologic studies detected a reduced vascularity in the atrophic optic nerve. Pallor of the optic nerve head seems to result from alterations in the tissue reflectance and translucency following axonal loss and glial reorganization rather than from a decreased microvascular bed.

Animals↗
PubMed1992

Comparison of computer-assisted versus manual optic nerve head pallor measurement.

Computerized methods of examining the optic nerve head offer the possibility of providing consistent, reliable, and accurate measurements of the nerve head. The reliability and accuracy of such instruments must be examined to confirm this. This research was undertaken to gain an insight into the accuracy of such a system, which takes its measurements by tracking the luminance boundaries of the pallor area and the optic nerve head after an observer marks the starting points. Measurements made using the computer-tracked boundary were compared with those made using a boundary tracked by an image-processing system of greater sophistication, the human visual system. The comparison was made with images from one eye from each of 30 subjects (10 normal, 10 ocular hypertensive, and 10 glaucomatous). The measurements were made by two observers. Each observer made each set of measurements twice, and the results were analyzed with a five-factor analysis of variance. The measurements made using the computerized method did not differ significantly from those made using the manual boundary tracking for the two observers, and they were highly correlated (r = 0.99 for the area pallor-disc ratio). Significant differences (P < 0.05) were found between the two observers in both the manual and computerized boundary tracking. The computerized method, however, did not find differences between the two sets of measurements made by each observer; the manual method did show such differences. The computerized method appeared to trace the luminance boundaries successfully in the image, and it might reduce errors related to the observer marking the starting points on different occasions.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1990

Pallor of the optic disc in children.

This report discusses the subject of pallor of the optic disc from the viewpoint of a paediatric neurologist. The paper is divided into two sections, one on optic atrophy in childhood and the second on optic nerve hypoplasia. Optic atrophy in children is a topic which is very poorly covered in standard textbooks either of neurology or ophthalmology. This review attempts to develop a working approach to the management of children who present with optic nerve atrophy as their primary neurological finding.

Child↗
PubMed1992

The pathology of the posterior root ganglia in AIDS and its relationship to the pallor of the gracile tract.

The spinal cord and the thoracic and lumbar posterior root ganglia (PRGs) of 14 HIV-positive men and 7 age- and sex-matched controls were studied by routine histology, morphometric analysis of the number of nodules of Nageotte (nN) and the diameters of sensory ganglion cells, immunohistochemistry and in situ hybridization. In 7 patients (2 of whom had evidence of cytomegalovirus ganglionitis) there were increased numbers of nN and diffuse, mild infiltration with CD45R+ T lymphocytes; no B lymphocytes were observed. Macrophages were increased in number in all cases. Whenever more than one ganglion was examined from the same patient, the appearances were similar in all. There was no alteration in the distribution of ganglion cell diameters. Changes in the spinal cord included vacuolar myelopathy (5 cases), HIV myelitis (1 case), microglial nodules (3 cases) and pallor of the gracile tracts (GTP) in 7 cases, in 6 of whom it co-existed with increased numbers of nN. Seven cases had no abnormalities, except the increase in number of macrophages in PRGs. In spite of a correlation between sensory nerve cell loss and GTP our findings suggest that other mechanisms, such as 'dying back' may contribute to the pathogenesis of GTP. Moreover, sensory disturbances were found most commonly in association with nerve cell loss; however, loss of sensory ganglion cells was not necessarily associated with evidence of sensory impairment.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Pallor and pica.

Explore the source record for details and available documents.

Anemia, Hypochromic↗
PubMed1979

The pallor of the optic disc. A quantitative photographic assessment by purple filter.

By employing purple colour filters with a large blue and a small red transmission, normal and atrophic optic disks were photographed on colour transparencies. Normal optic disks reflect red light, and atrophic optic disks reflect blue light. The degree of atrophy estimated by colour contrast is quantitated by microdensitometry in the blue (470 nm) and in the red (640 nm) region of the transparencies. The difference between the blue and red density is used as an expression of optic disc colour.

Atrophy↗
PubMed1978

The optic disc in glaucoma, III: diffuse optic disc pallor with raised intraocular pressure.

Ten patients (14 eyes) with chronic simple glaucoma are described, each with features atypical for this disease and more suggestive that each had suffered an acute ischaemic optic neuropathy. Diagnosis of an acute ischaemic optic neuropathy in these cases is important, as treatment of ocular hypertension in the contralateral 'normal' eye may prevent a similar attack. Optic nerve disease and visual loss in chronic simple glaucoma probably occur as a result of several different mechanisms. Sudden field loss following an acute ischaemic optic neuropathy may be only one of them.

Aged↗
PubMed1990

Usefulness of physical examination in detecting the presence or absence of anemia.

Previous studies addressing the usefulness of pallor in anemia are deficient because of observer or spectrum bias. Three internists made individual assessments of conjunctivae, face, nails, palms, and palmar creases in 98 male and 5 female hospitalized patients at a Veterans Administration Medical Center. The true-positive rates (sensitivities) were highest for pallor at any one of three sites (ie, the conjunctivae, face, or palms; 0.65) and for pallor of the palms (0.53). True-negative rates (specificities) were best for palmar creases (1.00), for pallor at conjunctivae, face, and palms (all three in combination; 0.95), and for the face (0.90). Receiver operator characteristic curve analysis revealed that the examination of the nailbeds is inferior to all other sites or combinations. Interobserver variability K scores were negative for palmar creases but ranged from .16 to .51 for other sites. We conclude that (1) the absence of pallor does not rule out anemia, and therefore this sign is not useful for screening an asymptomatic population; (2) pallor of the conjunctivae, face, and palms together is of benefit in confirming the presence of anemia; and (3) neither the nailbeds nor palmar creases are of value in assessing the presence or absence of anemia.

Anemia↗
PubMed1991

Increased preferential optic disc asymmetry in ocular hypertensive patients compared with control subjects.

The authors determined asymmetrical differences in optic disc cupping and pallor between the right and left eyes of 57 control subjects and 75 patients with ocular hypertension. Photogrammetry was used to measure the optic disc cup, and computerized image analysis was used to measure the optic disc pallor for the total disc and its quadrants. Generally, for control and ocular hypertensive eyes, the median values of cupping and pallor were significantly larger in the left eye than in the right, except for depth in the inferior quadrant (right eye minus left eye = 9.3%, P = 0.000) and pallor in the nasal quadrant (right eye minus left eye = 21.3%, P = 0.01), which were preferentially larger in the right eye than in the left in ocular hypertensive eyes. Ocular hypertensive eyes also showed a greater difference between the right and left eyes compared with control eyes for inferior depth (P = 0.06) and nasal pallor (P = 0.02). Detection of optic disc differences as a sign of ocular hypertension between the right eye and the left should evaluate the inferior and nasal quadrants of the disc.

Aged↗
PubMed1992

Further observations on the pathology of subcortical lesions identified on magnetic resonance imaging.

We performed postmortem magnetic resonance imaging and pathologic examinations on the brains of seven consecutive patients older than 50 years of age who died of non-neurologic causes. Multiple hyperintense subcortical lesions were identified in each patient, and a total of 29 lesions were examined histologically (eight rims, six caps, six punctate lesions, and nine patches). Rims were characterized by subependymal gliosis and loss of the ependymal lining; caps were associated with myelin pallor, gliosis, and arteriosclerosis; punctate lesions were characterized by dilated perivascular spaces and perivascular gliosis; and patches were associated with myelin pallor and dilated perivascular spaces. The pattern of myelin pallor defined the size and shape of caps and patches. Arteriosclerosis was identified in six of six caps, three of six punctate lesions, and in three of nine patches. These data indicate that (1) each type of hyperintense subcortical lesion has a distinct pathologic correlate; (2) arteriosclerosis is not invariably associated with all types of hyperintense subcortical lesions on magnetic resonance imaging; and (3) myelin pallor appears to contribute to the magnetic resonance imaging signal at 1.5 tesla.

Aged↗