The interpretation of automated visual fields.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
F S Mikelberg
Publications and source records attributed to F S Mikelberg.
Metastatic small-cell carcinoma of the lung. A photo essay.
Explore the source record for details and available documents.
Anterior Chamber↗
Pattern electroretinograms from hemifields in normal subjects and patients with glaucoma.
PURPOSE: Because glaucomatous visual field loss predominantly occurs in one hemifield, a baseline ratio of pattern electroretinogram (PERG) hemifield amplitudes (upper field:lower field) was determined in normal subjects and then examined in patients with glaucoma. METHODS: In 26 normal subjects and eight patients with glaucoma with typical arcuate field loss involving the test area (central 20 degrees), hemifield PERGs were recorded using checkerboard screens of check size 0.5 degrees and frequency 3.75 reversals per second (transient) and 15 reversals per second (steady state). RESULTS: The ratios obtained for normal central upper:lower amplitudes were 0.95 +/- 0.13 (transient) and 0.93 +/- 0.10 (steady state Fourier second harmonic). Wide nasal-field (52 degrees x 42 degrees) PERG ratios recorded on two subjects confirmed that the ratio held across large retinal areas. The ratio did not change with age or check size. The ratio showed less variability between patients than PERG amplitudes. In the patients with glaucoma, the hemifield PERG amplitude correlated with summed visual field thresholds for that area. Patients with glaucoma could be discriminated from normals by an abnormal ratio (> 2 SD) in seven of the eight patients. In two additional patients with more peripheral scotomas, the ratio remained normal. CONCLUSIONS: In normals, the upper:lower hemifield PERG ratio is slightly < 1.0 and remains stable with age. In glaucoma, visual field defects are associated with PERG reductions in the corresponding hemifield. An abnormal PERG hemifield ratio can be found in many patients, although more peripheral and symmetrical losses may still be missed.
Adult↗
Intraocular pressure and glaucoma.
Explore the source record for details and available documents.
Glaucoma↗
Axonal loss in band atrophy of the optic nerve in craniopharyngioma: a quantitative analysis.
Automated image analysis was used to examine the optic nerves of a patient with previous craniopharyngioma and bitemporal hemianopsia. On histologic study the right optic nerve showed extensive damage, and the left optic nerve showed a band of damage horizontally across the nerve. Automated image analysis of the left nerve showed that the superior and inferior poles of the nerve had lost approximately 50% of their total nerve fibres, indicating that these areas contain a mixture of crossed and uncrossed fibres; the temporal portion showed a variable amount of loss. To our knowledge this is the first report illustrating quantitatively the pattern of axonal loss in this type of lesion.
Adult↗
Do computerised visual fields and automated optic disc analysis assist in the choice of therapy in glaucoma?
The choice of therapy in patients with glaucoma is determined by the presence of damage in the visual field or optic disc or by change in the appearance of the optic disc or visual field over time. Computerised visual fields and automated optic disc analysis can assist in this determination. Automated optic disc analysis permits the measurement of neuroretinal rim area which is more closely related to the presence of pathology than cup/disc ratio. Simple ophthalmoscopic techniques may also be used to estimate the size of the neuroretinal rim area. Automated perimetry allows accurate diagnostic information to be obtained in a reliable manner. This permits easier diagnosis of glaucoma as well as easier long term follow up for change. The availability of automated techniques in ophthalmology has helped the clinician in the choice of therapy. The use of astute clinical judgement remains however of the utmost importance.
Diagnosis, Computer-Assisted↗
Light-sense, flicker and resolution perimetry in glaucoma: a comparative study.
A total of 106 eyes of 106 patients with different types of glaucoma were examined by automated light-sense, flicker and resolution perimetry (Humphrey Field Analyzer, program 30-2; flicker perimeter as described by Lachenmayr [16, 18]; resolution perimeter as devised by Frisén [4, 6, 8-11]). The fields were classified in a masked fashion as being normal or as having purely diffuse loss, purely localized loss or diffuse as well as localized loss. As compared with light-sense perimetry, resolution perimetry had a markedly lower sensitivity in the detection of glaucomatous damage (77%) but a high specificity (93%); the comparison of resolution perimetry with flicker perimetry showed similar results (sensitivity, 75%; specificity, 85%). When flicker perimetry was compared with light-sense perimetry and vice versa, the sensitivity was high (95% and 94%, respectively), but the specificity was low (57% and 62%, respectively). The prevalence of detection of diffuse loss by both light-sense and resolution perimetry was related to visual acuity, whereas flicker perimetry did not show such a relationship.
Adult↗
Relation between optic nerve axon number and axon diameter to scleral canal area.
To determine whether there are more axons present in eyes with larger optic discs, the authors studied 16 eyes from 16 individuals whose eyes were donated for corneal transplantation. For each nerve, the axon count, axon diameter, and scleral canal area was measured. Total axon count decreased with age. Mean axon diameter increased with age. There was no statistically significant relation detected between axon count and scleral canal area. Multiple regression revealed that when corrected for the effect of age, eyes with smaller scleral canal areas had larger number of axons.
Adult↗
Possible significance of cilioretinal arteries in low-tension glaucoma.
Cilioretinal arteries arise from the short posterior ciliary artery circulation or directly from the choroidal circulation. The presence of a cilioretinal artery may in compromised discs steal flow from the peripapillary circulation and account for worsening glaucoma damage. We reviewed the records of 33 patients with unilateral cilioretinal arteries admitted for investigation of low-tension glaucoma. We looked for absolute difference between the affected and unaffected eyes as well as percent difference relative to the mean value for the two eyes and to the value for the unaffected eye in the following variables: mean defect, corrected loss variance or corrected pattern standard deviation, and adjusted neuroretinal rim area. No statistically significant differences were found. The mean disc area for the eyes with cilioretinal arteries was significantly larger than that previously reported for normal eyes. The results suggest that if vascular steal exists because of the presence of this artery, it is not of major clinical importance.
Ciliary Body↗
The normal human optic nerve. Axon count and axon diameter distribution.
Computerized image analysis was used to determine the normal axonal count and axon diameter distribution in 12 normal human eyes. Mean axon count per nerve was 969,279 +/- 239,740 and mean axon diameter was 0.72 +/- 0.07 micron. Multiple linear regression disclosed 4909 axons lost yearly (P = 0.08). Statistical analysis did not show a relationship between axon diameter and age or time to fixation. The inferotemporal sector of the nerve had the highest fiber density (P = 0.02). The superonasal nerve had higher mean diameters (P = 0.02). This study may provide a baseline for future pathologic studies.
Adolescent↗
Reproducibility of computerized pallor measurements obtained with the Rodenstock Disk Analyzer.
Computerized pallor measurements of the optic nervehead were performed by global analysis with the Rodenstock Disk Analyzer. Total intervideographic and intravideographic variability was calculated. The coefficients of variation ranged from 8.3% to 20.08% for intervideographic variability of different pallor histogram values. The intravideographic variability for pallor histogram values ranged from 0.82% to 2.94%.
Analysis of Variance↗
Effect of acute medical reduction of intraocular pressure on the visual field and optic disc in ocular hypertension.
The effect of acute reduction of intraocular pressure (IOP) through oral administration of glycerol was assessed in 15 eyes of 15 patients with ocular hypertension by means of automated perimetry, Farnsworth-Munsell 100 hue testing, measurement of spatial contrast sensitivity with a laser interferometer and automated optic disc analysis. There was no significant relation between the absolute or relative change in IOP and the corresponding changes in any of the visual field or optic disc indices studied. The colour vision score increased significantly as the IOP decreased (p = 0.03). There was a significant reduction in the logarithm of spatial contrast sensitivity at grating sizes of 3 (p = 0.007) and 7.5 (p = 0.05) cycles per degree as the IOP decreased.
Adult↗
Measurement of optic nerve head pallor with a video-ophthalmograph and with computerized boundary analysis.
Optic disc pallor was recorded in 53 eyes of 53 patients by means of global analysis with a video-ophthalmograph (Rodenstock Disk Analyzer) and computerized boundary analysis. The coefficients of correlation between the values obtained with the Rodenstock Disk Analyzer and those obtained with boundary analysis were r = 0.24 (p = 0.08) at the 0.29 cutoff level, r = 0.39 (p = 0.004) at the 0.39 level and r = 0.46 (p = 0.0005) at the 0.50 level. Although the correlation was significant, the correlation coefficients were not high. The Rodenstock Disk Analyzer uses global analysis, which does not take into account the spatial relationship of the pallor on the disc, whereas boundary analysis is sensitive to spatial relationship, which may account for the poor correlation.
Adolescent↗
A study of the value of the central and peripheral isoptres in assessing visual field progression in the presence of paracentral scotoma measurements.
The visual field records of 45 eyes of 45 patients were evaluated to determine whether examination of the peripheral field of vision in patients with glaucoma and field defects adds useful information about the progression of visual field damage. The central scotoma mass, foveal sensitivity, and the central and peripheral mass of the visual field were quantified from measurements on the Tübinger perimeter. Most of the information on visual field progression was contained in the scotoma mass. When both scotoma mass and foveal sensitivity were known, central or peripheral isoptres did not add statistically significant information on progression. Evaluation of scotomas and assessment of central isoptres or of foveal sensitivity made perimetry of the peripheral isoptres redundant. The appearance of fresh peripheral scotomas or the quantification of changes in peripheral scotomas was not examined in the current study, and they would of course be important when they occurred.
Adult↗
Some observations on the relation between intraocular pressure reduction and the progression of glaucomatous visual loss.
A quantitative measure of visual field loss associated with kinetic perimetry in chronic open-angle glaucoma (COAG) is discussed. With this new technique an analysis of covariance is applied to a retrospective study of 41 COAG patients. It suggests that reduction of intraocular pressure may not be uniformly effective in controlling the progression of the disease.
Aged↗
The rate of progression of scotomas in glaucoma.
We conducted a retrospective study of 45 eyes of 45 patients with chronic open-angle glaucoma to evaluate the rate of progression of scotomas. "Scotoma mass" was calculated and regressed on time to obtain the rate of visual field change. Twenty-two eyes (49%) showed a linear type of progression, nine (20%) showed a curvilinear progression, three (7%) showed episodic progression, and 11 (24%) showed no significant progression. The mean scotoma mass was significantly lower in the curvilinear group than in the linear group.
Adult↗
The correlation between cup-disk ratio, neuroretinal rim area, and optic disk area measured by the video-ophthalmograph (Rodenstock analyzer) and clinical measurement.
The video-ophthalmograph (Rodenstock analyzer) records the topography of the optic disk via simultaneous stereoscopic video images which are stored and analyzed with the help of a microcomputer. We performed a prospective study of 49 eyes of 49 patients to compare the vertical cup-disk ratio, the horizontal cup-disk ratio, the neuroretinal rim area, and the optic disk area obtained with the video-ophthalmograph with those obtained with manual analysis of black-and-white stereoscopic photographs. The correlation coefficients were 0.67, for vertical cup-disk ratio (P = .0000), 0.63 for horizontal cup-disk ratio (P = .0000), 0.72 for neuroretinal rim area (P = .0000), and 0.89 for optic disk area (P = .0000).
Computers↗
Visual field examination in glaucoma.
Explore the source record for details and available documents.
Evaluation Studies as Topic↗