Visual Fields: 3 (American Academy of Ophthalmology Monograph Series)
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The impact of ocular blood flow in glaucoma. Prog Retin Eye Res ; Ocular haemodynamics and glaucoma prognosis: A color Doppler imaging study. Acute IOP elevation with scleral suction: Effects on retrobulbar haemodynamics. Pache M, Flammer J. A sick eye in the sick body? Systemic findings in patients with primary open-angle glaucoma. Systemic drugs and intraocular pressure. American Academy of Ophthalmology Monograph Series; 1 st edition; Primary open-angle glaucoma, intraocular pressure, and systemic blood pressure in general elderly population.
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The CV Mosby Co; 1 st edition; Ocular blood flow and systemic blood pressure in patients with primary open-angle glaucoma and ocular hypertension. Invest Ophthalmol Vis Sci ; Predictors of long-term progression in the early manifest glaucoma trial. Blood pressure during sleep: Am J Cardiol ; Systemic antihypertensive medication and incident of open-angle glaucoma.
Primary open-angle glaucoma, intraocular pressure, and diabetes mellitus in the general elderly population. Can diabetes be good for glaucoma? Why can't we believe our own eyes or data?
Simvastatin and disease stabilization in normal tension glaucoma: Mozzaffarieh M, Flammer J. Is there more to glaucoma treatment than lowering IOP. Surv Ophthalmol ; 52 Suppl 2: The mean topography of the three—scan series was used for the analysis HRT software ver 2.
Retinal Detachment
The contour line of the optic disc edge was drawn by one of the authors DFGH. The standard reference plane was used. Recruitment was restricted to the white ethnic group, because it is known that optic disc morphology can vary between different ethnic groups. The relationship between visual field locations and regions of the optic disc has been described previously. Neuroretinal rim area was recorded for the temporal three of the six predefined segments given in the HRT analysis.
Parameter differences between groups were assessed with a two-tailed t -test assuming unequal variance. The following correlations were assessed in the combined normal—glaucoma group: PERG amplitude and central visual field sensitivity, PERG amplitude and temporal neuroretinal rim area, and central visual field sensitivity and temporal neuroretinal rim area.
In addition, the relationship between age and PERG amplitude, central visual field sensitivity, and temporal neuroretinal rim area was investigated in the normal group. Correlations between measurements were sought by linear or quadratic regression analysis. The study population characteristics are summarized in Table 1. There was a range in severity of visual field loss in the glaucoma group. All parameter values were significantly lower in the glaucoma group. Temporal neuroretinal rim area did not correlate with age. These analyses were also significant when the normal and glaucoma groups were taken separately.
There was significant correlation between temporal neuroretinal rim area and central visual field mean DLS. These analyses were not significant when the normal and glaucoma groups were taken separately. There was significant correlation between temporal neuroretinal rim area PERG amplitudes. When assessing a patient with glaucoma, it is essential to estimate the amount of glaucomatous damage to set appropriate treatment targets.
The amount of glaucomatous damage is usually estimated from the magnitude of visual field loss and extent of neuroretinal rim loss in the optic disc. It is important to understand how field and rim loss are related to each other to identify correctly the stage of disease.
Similarly, when assessing the rate of glaucomatous progression, it is important to know whether the relationship between the amount of ganglion cell loss and the measurement of visual function is linear. If there is a curvilinear correlation of decibel DLS with ganglion cell number, then linear models of decibel DLS progression underestimate the rate of change when decibel DLS is near normal and overestimate the rate of progression when field loss is already moderately advanced. The results of this study confirm previous reports of a curvilinear relationship between neuroretinal rim area and decibel visual field loss Fig.
This finding is supported by the results of our study, which demonstrated large changes in PERG amplitude and corresponding small changes in decibel DLS when the central mean sensitivity was near normal Fig. In addition, in the individual patient, because of the high test—retest variability and the nonspecificity of diffuse sensitivity loss in the visual field, structural damage at the optic disc is frequently identified before reproducible visual field defects.
This adds to the impression of a functional reserve. Although the PERG and perimetry both test aspects of visual function, they differ in their nature. The PERG is an objective measure of massed ganglion cell responses to a suprathreshold stimulus, whereas perimetry depends on subjective responses to a threshold stimulus. Both the PERG amplitude and the perimetric response threshold might be expected to be determined by the relationship of stimulus area to ganglion cell density.
The stimulus areas are similar in both tests: The PERG stimulus was a 0. Neither test used stimuli scaled to account for changes in ganglion cell density with eccentricity. Thus, spatial summation effects are not accounted for in either test. This is in agreement with a previous study, 22 although the correlation in this study, using the HRT to quantify neuroretinal rim area, was slightly better than that in the previous report in which planimetry was used.
The neuroretinal rim area is a surrogate for, not a direct measurement of, ganglion cell number.
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It is a measure of ganglion cell axon cross-sectional area, of varying obliquity, depending on the course of fibers through the disc, together with other elements, such as supporting glia and blood vessels. These factors may explain the relatively poor correlation between the measurements of structure and function. Visual function declined with increasing subject age, and this largely, although not completely, explained the relationship between DLS and PERG amplitude in the normal group. However, the relationship between DLS and PERG amplitude in the combined normal—glaucoma group cannot be explained by age-related changes in visual function alone, because the relationship remained significant when age was introduced into the regression model.
Author Affiliations David F. Visual Field Defects in Chorioretinal Disorders. If the macula has been detached for a long time, central vision will not be regained, however, the patient will usually obtain useful navigational vision. The electrodes should be cleaned after use with each patient. The stimulus should be defined in terms of the visual angle of each check or the spatial frequency of bars or gratings. Same eye after re-attachment surgery with vitrectomy and silicone oil injection Photo:
The age-related rate of decline in decibel DLS in this study is almost identical with that reported by Heijl et al. It is important to consider possible confounding factors in the study. Most of the patients with glaucoma were taken from the general glaucoma clinic and, although concordance of optic disc and visual field change was not a requirement for entry into the study, the diagnosis of glaucoma often requires such concordance. However, all patients had ocular hypertension at diagnosis and had reproducible visual field defects, and it is not thought that patients with these features would be excluded from the clinic if nonconcordant optic disc change were present.
If this bias is present, it may affect strength of the optic disc—visual function relationship, but probably not the linear—curvilinear pattern. However, the age-related decline in ganglion cell numbers, estimated at approximately 0. Senile miosis has been implicated, 39 although this cannot explain the age-related change in some protocols. This was not the case in the combined normal and glaucoma group, in which glaucoma-related ganglion cell loss was presumably an important factor. The likely effect of the age-related factors is to increase the strength of the DLS—PERG relationship but not the linear—curvilinear pattern.
Submitted for publication November 6, ; revised February 25, ; accepted March 15, The publication costs of this article were defrayed in part by page charge payment. View Original Download Slide. The position of the PERG stimulus overlaid on a fundus photograph. The stimulus check size is 0.
The stimulus area and check size are to scale. The stimulus size is 0. The stimulus spacing and size are to scale. The box encloses the points included in the analyses to compare with PERG amplitudes and neuroretinal rim areas. The relationship between the central visual field and optic disc, derived from a published optic disc—visual field map. Plot of central visual field mean sensitivity in decibels against temporal neuroretinal rim area. Advanced Glaucoma Intervention Study.
Scoring systems for measuring progression of visual field loss in clinical trials of glaucoma treatment. Optic disc parameters and onset of glaucomatous field loss. Motolko M, Drance SM. Features of the optic disc in preglaucomatous eyes. The mode of progressive disc cupping in ocular hypertension and glaucoma. Rate and pattern of neuroretinal rim area decrease in ocular hypertension and glaucoma. Zeyen TG, Caprioli J.
Progression of disc and field damage in early glaucoma. Ganglion cell losses underlying visual field defects from experimental glaucoma. Invest Ophthalmol Vis Sci.
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Scaling the hill of vision: Relationship of optic disc topography to optic nerve fiber number in glaucoma. Neuroretinal rim areas and visual field indices in glaucoma. Correlation between mean visual field loss and morphometric optic disk variables in the open-angle glaucomas. Relationship between perimetric light sensitivity and optic disc neuroretinal rim area. Wall M Wild JM eds. Quantitative morphologic and functional evaluation of the optic nerve head in chronic open-angle glaucoma.
Maffei L, Fiorentini A. Electroretinographic responses to alternating gratings before and after section of the optic nerve.
Visual Fields: Examination and Interpretation, 3rd edition contains revisions and American Academy of Ophthalmology Monograph Series. Editorial Reviews. About the Author. Dr. Thomas Walsh is the neuro- ophthalmologist at the Visual Fields: 3 (American Academy of Ophthalmology Monograph Series) 3rd Edition, Kindle Edition. by Thomas Walsh (Editor).
Clinical and experimental evidence that the pattern electroretinogram PERG is generated in more proximal retinal layers than the focal electroretinogram. Ann NY Acad Sci. Pattern electroretinography PERG and an integrated approach to visual pathway diagnosis.