Visual Field Mean Defect Research Articles

Anisometropia and degree of optic nerve damage in chronic open-angle glaucoma

PURPOSE: To address the question of whether the refractive error plays a role in the amount of optic nerve damage in glaucoma, we intraindividually compared inter-eye differences in refractive error with inter-eye differences in parameters indicating the degree of glaucomatous optic nerve damage, and we interindividually correlated refractive error with neuroretinal rim area and visual field loss. DESIGN: Comparative clinical observational study. METHODS: This comparative clinical observational study was conducted in a university eye hospital. The study included 1,444 eyes of 876 patients with primary or secondary chronic open-angle glaucoma. Patients with a highly myopic refractive error (≥ −8 diopters) were excluded, owing to differences in the anatomy of the optic nerve head. Color stereo optic disk photographs were taken and morphometrically evaluated. The main outcome measures were refractive error, neuroretinal rim area, horizontal and vertical cup/disk diameter ratios, and visual field loss. RESULTS: In an interindividual statistical analysis, area of neuroretinal rim, horizontal and vertical cup/disk diameter ratios, and mean visual field loss were not significantly ( P > .10) correlated with refractive error. In an intraindividual comparison, inter-eye differences in refractive error were not significantly ( P > .05) correlated with inter-eye differences in neuroretinal rim area and mean visual field defect. The eye with the more myopic refractive error and the contralateral eye with the less myopic refractive error did not vary significantly in neuroretinal rim area and mean visual field defect. CONCLUSIONS: For nonhighly myopic (< −8 diopters) patients with primary or secondary chronic open-angle glaucoma, the refractive error may not play a major role for the amount of glaucomatous optic neuropathy. For nonhighly myopic (< −8 diopters) patients with primary or secondary chronic open-angle glaucoma, myopia may not be an important risk factor for glaucoma.

Plasma Levels of Endothelin-1 in Retinitis Pigmentosa

Retinitis pigmentosa (RP) is an inherited retinal disorder clinically characterized by a pale, waxy optic nerve head, attenuated retinal blood vessels and bone spicule pigment in the retina. Hemodynamic studies have demonstrated that RP is associated with a reduction in the retinal and choroidal blood flow. Retinal hemodynamic impairment is also present in the early stages of RP and various hypotheses have been advanced as to its cause. The authors studied 20 patients, 12 males and 8 females, aged between 26 and 42 years (mean 34.6 years) affected by simplex RP. The twenty patients were divided in two groups according to the degree of sight impairment: group A consisted of 10 patients with a visual acuity of 0.3 ± 0.1, visual field mean defect 18.988 ± 3.419 dB and b-wave electroretinogram amplitude of 13.14 ± 0.308 µV. Group B consisted of 10 patients with a visual acuity of 0.8 ± 0.2, visual field MD 10.523 ± 3.582 dB and b-wave electroretinogram amplitude of 26.000 ± 0.757 µV. An increase in plasma levels of endothelin-1 (ET-1) was found as compared with healthy controls: 1.910 ± 0.617 pg/ml vs. 1.180 ± 0.210 pg/ml (p < 0.021), but there was no statistical difference between group A and B (p < 0.163). It is thought that an increase in ET-1 and retinal oxygen levels in RP could lead to vasoconstriction and a decrease in the retinal blood flow worsening the abiotrophic process.

Correction for corneal polarization axis improves the discriminating power of scanning laser polarimetry

PURPOSE: Corneal polarization axis (CPA) has been reported to affect retardation measurements obtained with scanning laser polarimetry (SLP). The purpose of this investigation was to prospectively determine whether correction for CPA improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.DESIGN: Cross-sectional analysis of normal and glaucomatous eyes.METHODS: We constructed a noninvasive slit-lamp-mounted device incorporating two crossed linear polarizers and an optical retarder to measure the slow axis of corneal polarization. Complete ocular examination, standard automated perimetry, SLP imaging, and CPA measurements were performed on normal and glaucomatous eyes. One eye/subject was enrolled; if both eyes of a patient were eligible for the study, the right eye was selected. For each of the 13 SLP parameters, logistic regression was used to determine if including CPA in the model influenced the ability to discriminate between normal and glaucomatous eyes.RESULTS: Forty-three normal eyes (average visual field mean defect, −0.53 ± 1.4 dB) and 33 glaucomatous eyes (average visual field mean defect, −5.93 ± 6.5 dB) were enrolled. CPA was significantly correlated with summary retardation parameters (average thickness and integral values) in normal (r = 0.72–0.83, P < .001 for all values) and glaucomatous eyes (r = 0.43–0.62, P = .013 to < .001). Including CPA in the model improved the ability to discriminate between normal and glaucomatous eyes for five retardation parameters quantifying retinal nerve fiber layer (RNFL) thickness (range of P values: 0.045–0.001). For inferior average thickness, area under the receiver operating characteristic (ROC) curve increased significantly (P = .002) from 0.70 to 0.78 after accounting for CPA; with a sensitivity set at 80% specificity improved from 33% to 72%. Correlations between visual field corrected pattern standard deviation and average thickness, ellipse average, superior average, and inferior average significantly increased (range of P values, .018–.001) after adjustment for CPA (r = −0.35 and −0.45, −0.38 and −0.47, −0.46 and −0.57, and −0.42 and −0.49, respectively).CONCLUSIONS: Correction for CPA significantly increases the correlation between retinal nerve fiber layer structural damage and visual function and significantly improves the discriminating power of SLP for detection of mild-to-moderate glaucoma.

Polarimetric Measurement of Retinal Nerve Fiber Layer Thickness in Glaucoma Diagnosis

To evaluate reliability and diagnostic value of polarimetric measurements of the retinal nerve fiber layer (RNFL) thickness in the diagnosis of glaucoma. The study included 81 eyes with perimetric glaucoma with glaucomatous changes of the optic disc and visual field defects; 52 eyes with preperimetric glaucoma with glaucomatous optic disc abnormalities and normal achromatic visual fields; and 70 normal eyes. For determination of reliability, four examiners repeated polarimetric measurements five times in ten normal subjects. The polarimetric variables were significantly correlated with increasing mean visual field defect and decreasing neuroretinal rim area. In correlation analyses with visual field defects, correlation coefficients were highest for the variable "superior/nasal ratio" and "the Number," a variable calculated by the neural network of the device. In correlations with neuroretinal rim area, correlation coefficients were highest for measurements of the inferior nerve fiber layer thickness. The preperimetric glaucoma group and the control group differed significantly in the variables "superior/nasal ratio" and "the Number" and, to a smaller degree, in the variables "superior/temporal ratio" and "superior/inferior ratio." The Number variable had a sensitivity of 82% and 58% at a predefined specificity of 80% in separating perimetric glaucoma patients and preperimetric glaucoma patients, respectively, from control subjects. Reproducibility of the polarimetric measurements ranged between 70% and 89%. Polarimetric measurements of the RNFL thickness can detect glaucomatous optic nerve damage in patients with visual field loss, and in some patients with preperimetric glaucomatous optic nerve damage. Considering the fast performance, easy handling, and low maintenance costs, RNFL polarimetry may be helpful in glaucoma diagnosis.

Heidelberg retina tomography and optical coherence tomography in normal, ocular-hypertensive, and glaucomatous eyes

Purpose To evaluate optic disc and retinal nerve fiber layer (RNFL) appearance in normal, ocular-hypertensive, and glaucomatous eyes undergoing confocal scanning laser ophthalmoscopy and optical coherence tomography (OCT). Design Prospective, cross-sectional study. Participants Seventy-eight eyes of 78 consecutive normal (n = 17), ocular-hypertensive (n = 23), and glaucomatous subjects (n = 38) were enrolled. Methods Each patient underwent complete ophthalmic examination, achromatic automated perimetry, confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomography [HRT]), and OCT. Topographic HRT parameters (disc area, cup-disc ratio, rim area, rim volume, cup shape measure, mean RNFL thickness, and cross-sectional area) and mean OCT-generated RNFL thickness were evaluated in each group. Main outcome measures OCT and HRT assessment of optic disc and RNFL anatomy. Results OCT RNFL thickness showed no difference between normal and ocular-hypertensive eyes ( P = 0.15) but was significantly less in glaucomatous eyes ( P < 0.001). HRT measurements of rim area, cup-disc ratio, cup shape measure, RNFL thickness, and RNFL cross-sectional area were significantly less in glaucomatous eyes (all P < 0.005) and were correlated with mean OCT RNFL thickness (all P < 0.02). RNFL thickness using OCT or HRT was highly correlated with visual field mean defect during achromatic perimetry ( P < 0.0001). Conclusion Both HRT and OCT can differentiate glaucomatous from nonglaucomatous eyes. RNFL thickness measurements using OCT correspond to disc topographic parameters using HRT.

Pattern of early visual field loss in HIV-infected patients.

To determine the topographic pattern of visual field loss, if any, and its relationship to the stage of disease in human immunodeficiency virus-positive patients without infectious retinopathy. A total of 151 eyes from 81 alert and cooperative patients with human immunodeficiency virus were evaluated with visual field testing. Results were analyzed relative to the associated underlying nerve fiber layer patterns associated with retinal ganglion cell axons as they traverse the retina to the optic nerve. The stage of visual field loss was analyzed relative to the length of survival using Kaplan-Meier survival analysis. No correlation of CD4 cell count with visual field mean defect (r2 = 0.23) or corrected pattern standard deviation (r2 = 0.00) was found. A pattern of visual field loss, consistent with sparing of the papillomacular bundles and associated with damage primarily to the inferior retina external to the posterior pole, was found. Survival analysis indicated a significant difference in time of survival between individuals with normal visual fields and those with a diffuse visual field loss, with a trend to less survival with increasing field loss severity. These results are consistent with disease at the level of the optic nerve. The relationship of stage of visual field loss to survival has important implications for early detection of field loss and appropriate therapeutic intervention to maintain function and quality of life.

Optic disc morphology in pigmentary glaucoma

AIMTo evaluate the morphology of the optic nerve head in eyes with pigmentary glaucoma.METHODSColour stereo optic disc photographs of 62 patients with pigmentary glaucoma and 566 patients with primary open...

Optic neuropathy associated with sleep apnea syndrome

Objective The study aimed to determine ocular abnormalities in sleep apnea syndrome (SAS), an entity characterized by repetitive upper airway obstructions during sleep, inducing hypoxia and sleep disruption with the risk of cardiovascular and neurologic sequelae. Design The study design was a case series. Participants Nine patients referred for evaluation of suspected SAS participated. Intervention Complete ophthalmologic examination, including computerized perimetry, was performed. Main outcome measures Correlations between the respiratory disturbance index (RDI) during night sleep, a value used to diagnose and to grade SAS, and visual field indices using the Spearman rank correlation coefficient (r s) were measured. Results One patient was excluded from the statistical analysis because of optic nerve drusen with constricted visual fields, another because of tiled discs with corresponding temporal visual field defects. All three patients with severe SAS and one patient with moderate SAS had relative nasal arcuate visual field defects; two patients with severe SAS also had paracentral relative defects. One patient with normal polysomnographic result and two patients with mild or moderate SAS had normal visual fields. The RDI correlated positively with the mean visual field defect (r s = 0.81, P < 0.05) and with the visual field loss variance (r s = 0.78, P < 0.05). The clinical ophthalmologic examination results were normal in all seven patients. In two of the three patients with severe SAS treated with continuous positive airway pressure (CPAP), visual field defects remained stable over 18 months. The patient with optic nerve drusen also had severe SAS and was, therefore, treated with CPAP. His constricted visual fields improved dramatically after treatment. Conclusions Visual fields of patients with SAS showed defects consistent with an optic neuropathy. The CPAP therapy seems to stabilize or even reverse visual field defects.

Comparison of measurements of neuroretinal rim area between confocal laser scanning tomography and planimetry of photographs

BACKGROUNDTo compare neuroretinal rim area measurements by confocal scanning laser tomography and planimetric evaluation of optic disc photographs.METHODSFor 221 patients with primary and secondary open angle glaucoma, 72 subjects with...

Correlation Between Mean Visual Field Loss and Morphometric Optic Disk Variables in the Open-angle Glaucomas

To correlate morphologic changes of the optic disk with mean visual field defect in glaucoma. Color optic disk photographs of 302 patients with primary open-angle glaucoma, 53 patients with pseudoexfoliative glaucoma, and 55 patients with normal-pressure glaucoma were morphometrically evaluated. The data were correlated with mean visual field defect. The correlation between mean visual field defect and neuroretinal rim area was similar to a logarithmic function. The visual field deteriorated slightly in the early stage and markedly in the advanced stages of glaucoma. A discrepancy between normal visual field and abnormal optic disk occurred more often in young than in old patients. Neuroretinal rim shape, total rim area, and rim area in the temporal inferior and temporal superior disk sectors correlated best with mean visual field loss. Alpha and beta zones of peripapillary atrophy and diameter of retinal arterioles were less clearly correlated. Calculated rim variables that were corrected for optic disk area did not markedly improve the correlation coefficients. In eyes with normal visual fields, rim shape was the most important disk variable for detecting glaucomatous optic nerve damage. There were no patients with glaucomatous visual field loss and an unremarkable optic disk. In early glaucoma, changes are more marked in optic disk appearance than in the visual field, suggesting that at least for some patients, for early glaucoma diagnosis, optic disk appearance is more important than perimetry, whereas for follow-up examination, perimetry may be more useful than optic disk morphometry. The most useful planimetric optic disk parameters are neuroretinal rim shape and rim area.

Optimizing the distribution and test locations in statistical perimetry. Preliminary results

Are short programs useful to glaucoma-screening? We investigated the concept of Program G1x with Octopus 1-2-3, which permits examination of various numbers of test locations i.e., 16, 32, 45, or all 59 test locations. Using 99 visual fields of glaucomatous or glaucoma-suspect right eyes, we compared mean defect (MD) and loss variance (LV) of the global visual field with MD and LV of the stages of G1x-program (standard strategy). The results showed that stage 1 of Program G1x underestimated the glaucomatous visual field damage present in the entire field. Thus, the use of only the first stage (16 test locations) of G1x is not advisable. At least 32 test locations, i.e., stages 1 and 2 of program G1x, are recommended for clinical perimetry.

Optic disc morphology in “age-related atrophic glaucoma”

This study was performed in order to evaluate whether, in primary open-angle glaucoma (POAG), patients with a different degree of fundus tessellation vary in optic disc morphology and level of intraocular pressure. Color stereo optic disc photographs of 562 patients with POAG and a myopic refractive error of less than -8 diopters were morphometrically examined. According to the degree of fundus tessellation, the total group was divided into a tessellated subgroup (n = 256) and a nontessellated subgroup (n = 306), both matched for neuroretinal rim area and refractive error. In the tessellated subgroup, as compared to the nontessellated subgroup, the mean maximal intraocular pressure values were significantly lower, the parapapillary atrophy was significantly larger, the optic cup was significantly more shallow, frequency of disc hemorrhages was lower, the mean visual field defect was significantly more marked, and patient age was significantly higher. Within the whole study group, the degree of fundus tessellation increased significantly (P < 0.005) with decreasing mean maximal intraocular pressure, decreasing optic cup depth, and increasing degree of parapapillary atrophy. In the subgroups with the highest degree of fundus tessellation, parapapillary atrophy was the greatest and the mean maximal intraocular pressure was the lowest compared to other subgroups. At the low-pressure end of POAG, marked fundus tessellation is associated with large parapapillary atrophy, shallow disc cupping, mostly concentric emaciation of the neuroretinal rim, and high patient age. The results suggest a distinct subtype of POAG in older patients with relatively low intraocular pressure leading to a mainly diffuse atrophy of the optic nerve.

Echographic Measurement of Optic Nerve Thickness Correlated With Neuroretinal Rim Area and Visual Field Defect in Glaucoma

To determine whether echographic measurements of the pial diameter of the optic nerve are significantly correlated with glaucomatous changes of the optic disk and retinal nerve fiber layer. In 31 patients with primary open-angle glaucoma and 16 normal control subjects, optic nerve thickness was determined by measuring the maximal pial diameter of the optic nerve using standardized A-scan echography. The optic disks were morphometrically examined using color stereo photographs, and the retinal nerve fiber layer was assessed using wide-angle red-free fundus photographs. Optic nerve thickness as measured echographically decreased significantly (P < .001) with decreasing neuroretinal rim area, diminishing visibility of the retinal nerve fiber layer, narrowing of the retinal arterioles, enlarging parapapillary atrophy, and increasing mean visual field defect. In an intraindividual bilateral comparison, side differences in the optic nerve thickness were significantly correlated with side differences in neuroretinal rim area (P < .0001), diameter of retinal arterioles (P = .003), and visual field defect (P < .0001). In the differentiation of normal and glaucomatous eyes, sensitivity and specificity were higher for echographic measurements of the optic nerve thickness than for parapapillary atrophy and diameter of retinal arterioles but worse than for determination of the neuroretinal rim area. Echographic measurements of optic nerve thickness are significantly correlated with glaucomatous changes of the optic disk and retinal nerve fiber layer. In patients with opaque media, echographic measurement of optic nerve thickness may be helpful in distinguishing among normal eyes, eyes with medium advanced glaucoma, and eyes with markedly progressed glaucoma.

Optic disc size and optic nerve damage in normal pressure glaucoma.

Recent reports indicate that eyes with normal pressure glaucoma have larger optic discs than eyes with primary open angle glaucoma or normal eyes. This study was performed to find whether, in normal pressure glaucoma, a large disc is associated with more optic nerve damage than a small disc. Colour optic disc photographs of 74 patients with normal pressure glaucoma were assessed morphometrically. Taking the study group as a whole, the optic disc size decreased significantly (p = 0.04) with increasing visual field defect. In an intraindividual bilateral comparison, the side differences in the disc area of the right minus the left eye of the same individual were not significantly correlated with the side differences in the mean visual field defect. The results indicate that the eye with the larger optic disc, when compared with the contralateral eye with the smaller optic nerve head, showed neither a significantly more marked nor less pronounced glaucomatous optic nerve damage. It suggests that for a given patient the degree of glaucomatous optic nerve atrophy was not markedly associated with the optic disc size. The finding that patients with large visual field defects had smaller discs than patients with moderate perimetric loss may indicate that the results of previous cross sectional studies reporting on an unusually large disc size in normal pressure glaucoma may be due partially to selection.

Determination of the neuroretinal rim area using the horizontal and vertical disc and cup diameters

This study evaluated whether the neuroretinal rim area can be calculated on the basis of the horizontal and vertical diameters of the optic disc and cup applying the formula of an ellipse. Color stereo optic disc photographs of 587 normal subjects and 1193 patients with glaucoma were morphometrically examined. In a first method, the areas of the optic disc and cup were planimetrically measured and the area of the neuroretinal rim was determined as optic disc area minus cup area. In a second method, the optic disc and cup were assumed to have an elliptical shape. Their areas were calculated by applying the formula of an ellipse, taking into account their horizontal and vertical diameters. As in the first method, the rim area was then determined as disc area minus cup area. The values of the neuroretinal rim area as measured using the first method differed by 0.05 +/- 0.05 mm2 from the values as calculated by the second method. The average error was 2.8 +/- 2.9% for the normal group and 8.2 +/- 20.8% for the glaucoma patients. It increased with decreasing neuroretinal rim area and increasing mean visual field defect. For clinical purposes, the neuroretinal rim area can be determined on the basis of the horizontal and vertical diameters of the optic disc and cup. The horizontal and vertical disc and cup diameters being determinable upon ophthalmoscopy, this finding is important for the direct measurement of optic disc morphology during any ophthalmoscopic examination.

Correlation of the Optic Disc Size to Glaucoma Susceptibility

AbstractPrevious studies have suggested that a larger optic disc size in blacks as compared with whites is related to the increased glaucoma susceptibility in blacks. In an intraindividual bilateral comparison of 245 white patients with open-angle glaucoma, the authors evaluated whether the glaucomatous optic nerve damage was greater or less in the eye with the larger optic nerve head. Highly myopic eyes were excluded. The difference in optic disc area of one eye as compared with the contralateral eye was not significantly correlated to the differences in visibility of retinal nerve fiber bundles and mean visual field defect between the two eyes. Mean perimetric loss and the retinal nerve fiber layer index were not significantly higher in the eye with the larger or smaller optic nerve head. This indicates that in whites, high myopes excluded, the susceptibility to glaucomatous optic nerve fiber loss may be independent of the optic disc size.

Papillenausmessung mit Planimetrie und “Optic Nerve Head Analyzer” bei Glaukom und Glaukomverdacht - Teil II: Korrelationen der Resultate der beiden Methoden mit Veränderungen des Gesichtsfeldes, untersucht mit dem automatischen Perimeter OCTOPUS

Sixty-seven optic nerve heads of 40 patients with proven or suspected glaucoma were measured by planimetry and with the Rodenstock Optic Nerve Head Analyser (ONHA). The results were compared to visual field indices obtained with the Octopus program G-1. Good correlation of the results obtained by the two measurement procedures has been shown (Stürmer et al. 1989), between values for the disk area, the excavation area, and the cup/disk ratio. However, there is only weak correlation of values for the neuroretinal rim. The planimetrically measured neuroretinal rim area in the total population examined proved to be significantly correlated only with the visual field index for mean retinal sensitivity (MS; r2 = 0.106; P = 0.007) and short-term fluctuations (SF; r2 = 0.066; P = 0.036). After division of the population examined into different diagnostic groups, further statistically significant correlations between optic nerve head parameters and the various visual field indices were shown; here, the cup/disk ratio of both measurement procedures in two subgroups showed the best correlation with the visual field indices MS and mean defect (MD). Neither in the total population nor in any of the subgroups was a statistically significant correlation found between the volume of the excavation and one of the visual field indices. Comparing only the data for the temporal quadrant of the optic nerve head with the visual field did not improve the correlations. The best, i.e. highly significant, correlations were between optic nerve head parameters and the age of the patient. The correlation factors are much lower than other published data. A variety of factors could be responsible for these weak correlations: different optic nerve head configurations on the one hand, and localized or diffuse visual field defects on the other. In unselected cases it appears impossible to predict the visual field of a given optic nerve head. Both methods are suitable for follow-up, but not all anatomical configuration of the optic nerve head permit this.

Correlation of Structure and Function in Glaucoma: Quantitative Measurements of Disc and Field

The relationship between quantitative structural measurements of the optic nerve head and quantitative measurements of the visual field in glaucoma was studied. Computerized videographic image analysis (Rodenstock Analyzer) was used to obtain cup-disc ratio, disc rim area, and cup volume in 50 glaucoma suspects and 37 glaucoma patients. The visual field indices, mean defect and loss standard deviation, were calculated from Octopus Program 32. There were statistically significant linear correlations between each of the optic nerve structural parameters and visual field mean defect and loss standard deviation. The strongest correlation was between disc rim area and visual field mean defect (r = −0.49), which are both global measures of glaucomatous damage. The correlations were not strong enough to readily allow the recognition of early nerve damage by the parameters analyzed thus far. Closer correlations may be evident if structural parameters can be found that more accurately reflect the number of surviving axons in the optic nerve head.