Visual evoked potentials in patients with Graves' ophthalmopathy complicated by ocular hypertension and suspect glaucoma or dysthyroid optic neuropathy

The study compared visual evoked potentials of patients with uncomplicated Graves' ophthalmopathy, patients with ophthalmopathy and elevated intraocular pressure or suspect glaucoma, and patients with dysthyroid optic neuropathy (DON). The aim of the study was to investigate the clinical potential for the visual evoked potentials (VEP) in the differential diagnosis among the groups. The VEPs were obtained from 43 subjects with endocrine ophthalmopathy. Group I included patients with uncomplicated ophthalmopathy (30 eyes); group II included patients with ophthalmopathy, intraocular pressure 23 mmHg with and without early visual field defects, and no evidence of apical crowding on coronal computed tomography scan (28 eyes); group III included patients with DON (28 eyes). Amplitude and latency of major component of pattern VEP were obtained at three visual angles (60', 30', 15'). Data from each group was compared with data from age-matched normal subjects. Disturbances of VEP were found mainly in patients of Group II and Group III. Control Group had normal VEP. About the differential diagnosis between Group II and Group III the most important parameter was the N75-P100 amplitude for 15' of pattern stimulation. Only for this visual angle, Group II and Group III had not overlapped N75-P100 amplitude. This study shows that VEP detect visual function abnormalities noninvasively in patients with complicated Graves' ophthalmopathy. Results also indicate the clinical potential for VEP in the differential diagnosis between patients suffering from ophthalmopathy complicated by ocular hypertension or suspect glaucoma and patients with dysthyroid optic neuropathy.     

Testing for glaucoma with frequency-doubling perimetry in normals, ocular hypertensives, and glaucoma patients

BACKGROUND: The aim of this study was to evaluate the diagnostic usefulness of the FDT perimeter protocol (C-20-5) in combination with a database system for analysis of single test locations. METHODS: One hundred seventy-three ocular hypertensive eyes, 116 "preperimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy, elevated intraocular pressure, no visual field defects in standard white-on-white perimetry), 199 "perimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy and visual field defects), and 151 control eyes underwent FDT screening and conventional white-on-white perimetry. Four repeated measurements were carried out in 15 glaucoma patients at 2-h intervals to judge reproducibility of all test locations. The present screening strategy begins testing at the normal 5% probability level. If a stimulus is not detected, further targets are presented. FDT-Viewfinder and statistics software were used for case-wise recalculation of all missed localized probability levels and correlation with corresponding test locations using conventional perimetry. RESULTS: Analysis of repeated measurements in patients reveals that variation of single test points can be considerable. However, the numbers of missed test-stimuli calculated globally or in quadrants are significantly correlated with corresponding Octopus visual field defects (Spearman rank correlation P<0.001). Using a predefined specificity of 96% in control eyes, 11% of ocular hypertensive eyes, 28.5% of "preperimetric" glaucoma eyes and 86.9% of "perimetric" glaucoma eyes have been classified glaucomatous using an overall score and with consideration of different cut-off points in right and left eyes. CONCLUSION: Point-wise analysis of FDT screening results can be helpful for classification of patient groups and consideration of the individual learning curve in repeated measurements. The C-20-5 protocol of the FDT perimeter is able to detect a considerable proportion of glaucomatous patients.     

Iris colour, optic disc dimensions, degree and progression of glaucomatous optic nerve damage

PURPOSE: To evaluate whether iris colour influences size and shape of the optic nerve head and risk for glaucoma progression. METHODS: The hospital-based observational study included 1973 eyes of 1012 Caucasian subjects with ocular hypertension or chronic open-angle glaucoma. For all patients, colour stereo optic disc photographs were evaluated, and corneal pachymetry and achromatic perimetry were performed. Main outcome measures were optic nerve head parameters, the development or progression of visual field defects and iris colour. RESULTS: In most of the study groups, size of the optic disc, neuroretinal rim, alpha zone and beta zone of parapapillary atrophy, retinal vessel diameter and central corneal thickness did not differ significantly between eyes with blue, green, brown and mixed iris colour. In the normal-pressure glaucoma group, neuroretinal rim area was smallest in the population with mixed-coloured eyes and largest in the group of eyes with brown irides (P = 0.001 after correction for inter-eye dependency and multiple testing). For the ocular hypertensive subjects and glaucoma patients with follow-up examinations, the rate of development or progression of glaucomatous visual field loss was not significantly associated with iris colour (P = 0.060). CONCLUSIONS: In Caucasian subjects, iris colour does not have a major association with the size of the optic nerve head structures, central corneal thickness and retinal arterial diameter. In Caucasian patients with ocular hypertension or chronic open-angle glaucoma, an influence of iris colour on the risk for development or progression of glaucomatous visual field defects could not be confirmed.     

Prognostic significance of the pattern visual evoked potential in ocular hypertension.

This paper reports a prospective study on 49 ocular hypertensive patients to evaluate the prognostic significance of transient abnormalities in the pattern visual evoked potential (VEP) in the development of glaucoma. Seven of 24 patients with VEP abnormalities at diagnosis of ocular hypertension developed glaucomatous field defects in the follow-up period as compared with none of 25 patients with normal VEPs at diagnosis. We conclude that appropriately designed pattern VEP testing is a valuable complement to careful (preferably computerised, static) perimetry. In addition, our findings support the contention that, in glaucomatous disease of the optic nerve, rudimentary pattern processing mechanisms--that is 'Y'-type units of the magnocellular pathways--may be affected earlier than luminance processing mechanisms.     

视觉诱发电位在挫伤眼视神经损伤的应用

目的探讨视觉诱发电位（VEP）对挫伤眼的视神经损伤诊断和鉴定的意义。方法对单侧眼挫伤59例（59眼）进行视力检查及VEP检查，以自体健侧眼为对照。按视力与VEP结果是否相符分为两组，相符者为A组，40例，占67．80％；不相符者为B组，19例，占32．20％。分析两组间VEPP100波幅值及P100峰潜时值。结果A组中伤眼VEPP100波幅明显降低，P100峰潜时明显延长，差异有统计学意义。B组有16例证实为伪盲，另3例伤眼眼睑、球结膜肿胀减退后视力好转。结论VEP对挫伤眼的视神经损伤的诊断和鉴定有重要价值。     

Concordance of parapapillary chorioretinal atrophy in ocular hypertension with visual field defects that accompany glaucoma development

OBJECTIVE: To determine whether the extent and location of progressive parapapillary chorioretinal atrophy noted in some patients with ocular hypertension are correlated with the extent and location of visual field defects that occur with progression to glaucoma. STUDY DESIGN: Retrospective cohort study. PARTICIPANTS: Thirty patients with ocular hypertension who had progressive changes of parapapillary atrophy develop before clinically detectable optic disc or visual field damage. Main Outcome Measures: Assessment of changes in the parapapillary atrophy and visual field parameters. METHODS: Baseline and follow-up optic disc photographs and visual field test results were retrospectively analyzed. The relationship between the extent of parapapillary atrophy observed during the ocular hypertension period and initial visual field abnormalities detected after glaucoma development, as well as their spatial relationship, was statistically analyzed. RESULTS: The extent of progressive changes of the parapapillary atrophy detected during the ocular hypertension period was correlated with the extent of changes in the visual field parameters, including corrected pattern standard deviation and mean deviation measured after glaucoma development (Mantel-Haenszel chi-square test, P = 0.026, P = 0.037, respectively). In addition, the visual field abnormalities occurred in the corresponding quadrants of the progressive parapapillary atrophy. Analysis of the spatial relationship revealed that the location of progressive changes of the parapapillary atrophy was concordant with the location of visual field abnormalities in 78% of the quadrants (94 of 120 quadrants) (chi-square test, P = 0.001). CONCLUSIONS: The extent and location of visual field abnormalities that develop in ocular hypertensive eyes with progression to glaucoma exhibit a concordance with the extent and location of progressive parapapillary atrophy noted in the ocular hypertension period. This suggests the importance of detailed examination of the parapapillary area in ocular hypertensive eyes.     

Contrast sensitivity and pattern visual evoked potential in patients with glaucoma

Contrast sensitivity and pattern visual evoked potential (VEP) were measured in cases of ocular hypertension and primary open-angle glaucoma at various stages. The visual field of each eye was examined quantitatively and the retinal nerve fiber layer and optic disc were precisely assessed with magnified stereoscope fundus photography.This study revealed that contrast sensitivity of the eyes with glaucoma was within the normal range in the very early stage of the disease. As optic nerve damage advanced, high-or low-frequency loss developed. Further optic nerve damage produced a level type of loss.Pattern VEPs also showed increasing abnormalities as glaucomatous optic nerve damage progressed. Measurements of contrast sensitivity and pattern VEP were found not to be as sensitive as quantified precise visual field measurment or color stereosopic fundus photography for detection of minor optic nerve damage in cases of early glaucoma. These methods may be useful, however, as an objective and subjective monitor of progression of optic nerve damage in glaucoma.     

A comparison between multifocal and conventional VEP latency changes secondary to glaucomatous damage

PURPOSE: To compare latencies of conventional visual evoked potentials (cVEPs) and multifocal VEPs (mfVEPs) in the same patients. Previous reports of prolonged cVEP latency suggest a vehicle for detecting abnormal ganglion cells and for monitoring neuroprotection. METHODS: Seventy-five glaucomatous eyes (47 patients), 75 eyes with suspected glaucoma (46 patients), and 41 control eyes (22 subjects) underwent achromatic automated perimetry and mfVEP and cVEP testing. The mfVEP stimulus was a scaled dart board with 60 sectors; each sector was a pattern-reversing checkerboard. The cVEP stimulus was a reversing checkerboard with checks of either 15 minutes or 60 minutes in width. RESULTS: Relatively few glaucomatous eyes had latencies that fell outside the range of control eyes, and there was little difference between the cVEP and mfVEP results. In the glaucoma group, 12.3% (15 minutes cVEP), 8% (60 minutes cVEP), and 17.3% (mfVEP) of the eyes and 5.3% (15 minutes cVEP), 6.7% (60 minutes cVEP), and 5.3% (mfVEP) of the suspect eyes exceeded the normal range. The glaucomatous eyes had, on average, relatively small increases in latency, compared with the control or suspect groups. Further, the latency of both the mfVEP and cVEP bore no obvious relationship to the mean deviation of the visual field. CONCLUSIONS: Contrary to previous reports, prolonged VEP delays were present in a minority of patients with glaucoma. Either a delayed VEP is not a good indicator of damaged, as opposed to dead, retinal ganglion cells, or there are relatively few patients who exhibit evidence of damaged ganglion cells.     

Nerve fiber layer and optic disc fluorescein defects in glaucoma and ocular hypertension

Photographs of the optic discs and fluorescein angiograms of 31 patients with open-angle glaucoma and 43 patients with ocular hypertension were evaluated for nerve fiber layer (NFL) defects and absolute fluorescein filling defects. All of the glaucomatous eyes showed both defects. Of the 43 ocular hypertensive eyes, in which both NFL and absolute fluorescein filling defects were evaluated, 9% had only NFL defects, 19% had only fluorescein filling defects, 14% had both defects, and 58% had neither defect. The percent area of fluorescein defect in the optic disc increased with severity of NFL defect in glaucoma and ocular hypertension. This study confirms the relationship of fluorescein filling defects and NFL defects to glaucomatous abnormalities and thus the association between vascular damage to the optic nerve and axon loss in glaucoma. The earliest objective evidence of glaucomatous damage can be detected with a combination of NFL evaluation and optic disc fluorescein angiography.     

Relationship between central visual field and pattern VECP in optic neuritis

We compared the visual field within 10 degrees with the latency and amplitude of the P100 component of pattern visually evoked cortical potentials (PVECPs) in optic neuritis. Twenty five eyes of 17 cases with optic neuritis suffered from multiple sclerosis (MS) and in 21 eyes of 17 cases optic neuritis was caused by unknown etiology. The visual field was tested by program 31 of the automated perimeter Octopus. PVECPs were recorded with a television system. The visual field was considered to be abnormal for when at least one abnormal point was found within a 10-degree field. P100 peak latency of PVECPs with above normal mean latency plus 2SD was defined as abnormally prolonged. The abnormalities found by 10-degree visual field and PVECPs latency correlated significantly both in cases of MS and unknown cause. The eyes with mean loss of over 4dB within a 10-degree visual field invariably had a delayed latency. Those with an abnormal central point or abnormal points in the lower part within 10-degree visual field had a delayed latency. The latency was estimated in relation to causes, age, visual acuity and visual field. The cases with worse vision or worse field showed a tendency to have a prolonged latency. In unilateral cases the ratio of PVECPs amplitude between affected eyes and healthy fellow eyes was studied. The eyes which had abnormal visual field within 10 degrees and a delayed latency showed reduced amplitude of at most 61% compared with that of the healthy fellow eyes(ABSTRACT TRUNCATED AT 250 WORDS)     

视觉诱发电位在颌面外伤致视神经挫伤诊断及预后中的应用

目的:应用视觉诱发电位检查颌面外伤致视神经挫伤程度,确定视功能损伤程度及预后估计。方法:对颌面外伤引起的单侧挫伤眼65例65眼进行治疗前、治疗后视觉诱发电位(visual evoked potontial,VEP)检查,以自体的健眼作为对照。结果:损伤眼视力及VEP的P100潜伏期及波幅异常,视力损害越重,VEP改变越明显,且预后越差。结论:VEP是视神经挫伤早期诊断,判断预后的客观检查方法。     

Visual evoked potentials under luminance contrast and color contrast stimulation in glaucoma diagnosis

PURPOSE: To evaluate the diagnostic value of visual evoked potential (VEP) assessment with luminance-contrast and color-contrast stimulation in the detection of glaucoma. PATIENTS AND METHODS: The study included 59 patients (96 eyes) with glaucomatous changes of the optic disc and visual field defects and 58 control eyes of 29 healthy patients. Four types of pattern VEP stimulation (0.9 cycle/degree) were performed in all patients: achromatic, alternating sine-wave stripe pattern: 6 reversals per second, contrast of 10% (activation of predominantly the magnocellular pathway); isoluminant, red-green stripe pattern: 83.3 milliseconds onset, 83.3 milliseconds offset, contrast of 30% and 80% (activation of predominantly the parvocellular pathway); and blue grating with yellow background adaptation: 200 milliseconds onset, 500 milliseconds offset (activation of the blue-sensitive pathway). RESULTS: The glaucoma group and the control group differed significantly (P < 0.01) in the peak times of all chromatic VEP responses and to a lesser degree in the achromatic VEP. Considering the amplitudes, only the low-contrast red-green stimulus showed a statistically significant reduction in glaucoma. At a predefined specificity of 90%, in separating patients with glaucoma from healthy control subjects, the peak time of the blue-yellow VEP had a high sensitivity (90%), whereas the sensitivity of the achromatic VEP was low (31%). The red-green VEP showed a sensitivity of 73% using low contrast and 71% using high contrast. In a paired correlation analysis with visual field defects, all stimulations showed significant (P < 0.05) results. Correlation coefficients were highest (R = 0.79, P < 0.01) for the peak time of the blue-yellow VEP. CONCLUSIONS: VEP measurements with presumable stimulation of single neuronal pathways can detect glaucomatous optic nerve damage in a considerable fraction of patients with visual field loss. Occipital responses to chromatic stimulation seem to be more sensitive to glaucoma damages than do responses to achromatic pattern reversal stimulation.     

Use of sequential Heidelberg retina tomograph images to identify changes at the optic disc in ocular hypertensive patients at risk of developing glaucoma

AIM: To determine if global and segmental changes in optic disc parameters of sequential Heidelberg retina tomograph (HRT) images develop in individual ocular hypertensive (OHT) patients without white on white visual field defects. METHODS: Patients and normal controls were recruited from a prospective ocular hypertension treatment trial. The subject groups consisted of 21 OHT patients who had converted to early glaucoma on the basis of visual field criteria (24-2 program on the Humphrey perimeter), 164 OHT subjects with normal visual fields, and 21 normal controls. Sequential HRT images 16-21 months apart were obtained for each subject and segmental optic disc parameters were measured to determine if any change had occurred. From the analysis of sequential HRT images of the 21 normal eyes we established normal limits of interimage variation. Individual discs in each group showing changes above the 95% limit of normal variability were then sought. RESULTS: Several segmental and global optic disc parameters were found to show significant change in the converter group before confirmed visual field change, confirming our previously published results. Individual optic disc analysis using the 95% limit of normal variability data demonstrated glaucomatous change in 13 out of 21 converter eyes. 47 of the 164 OHT eyes with normal visual fields showed change in global and segmental parameters in a "glaucomatous" direction above the level expected for normal variability. The parameters which changed most frequently in the OHT eyes were: global cup volume (6.7% of discs), inferonasal cup volume (11%), inferotemporal cup volume (8.5%), and superotemporal cup area (7.3%). CONCLUSIONS: We have identified change in a subset of ocular hypertensive patients which could predate the development of glaucomatous visual field loss. The HRT could be of value in the sequential follow up of those suspected of having glaucoma by identifying eyes at risk of developing glaucoma. However, further refinement of the technique is required to eliminate some of the inherent variability of the analysis method described, and to increase the ability to detect at risk individuals.     

Fluorescein angiography of the optic disc in ocular hypertension and glaucoma (author's transl)]

A fluorescein angiography of the optic disc has been performed on 62 eyes in 41 patients suffering from ocular hypertension or glaucoma. The angiogram was abnormal in 32 eyes. 11 eyes showed an absolute hypofluorescence involving the whole optic disc. 15 eyes showed an absolute hypofluorescence limited to a part of the cup and the rim. 6 eyes showed a late hyperfluorescence of the fundus of the cup. Total hypofluorescence throughout all phases of fluorescein angiogram corresponds to filling defects. Absolute hypofluorescence involving the whole optic disc is associated with visual field loss in all cases. Absolute hypofluorescence involving only an area of the optic disc is associated with a normal visual field in a few cases. It is postulated that the limited filling defects without visual fields defects may be an indication of impending loss of the visual field. Therefore fluorescein angiography could be helpful in clinical assessment of visual prognosis of chronic ocular hypertension and glaucoma. Nevertheless wider experience and followup are necessary to confirm the value of the method.     

Timolol treatment of chronic open-angle glaucoma and ocular hypertension

Maintenance effect of topical timolol was investigated or 2 years in a group of 125 glaucomatous and ocular hypertensive patients (231 eyes) who had been successfully treated with timolol alone during a 6-month period preceding this trial. Intraocular pressure (IOP) was controlled with timolol alone in 135 of 183 eyes (74%) that completed the study. At the end of the trial 142 eyes (78%) showed an IOP of less than 22 mmHg. Other glaucoma medication had to be added to timolol treatment in 18% of ocular hypertensive and 35% of glaucomatous eyes because of IOP elevation. Elevation of IOP seemed to be due to worsening of glaucoma rather than to decreased efficacy of timolol. None of the ocular hypertensive patients developed visual field defects but in ten glaucomatous patients progression of existing visual field defects was observed in association with elevated IOP. Transient adverse effects were observed in 13% of cases, but timolol treatment had to be stopped in only five cases (4%) because of side effects.     

Keratometry, optic disc dimensions, and degree and progression of glaucomatous optic nerve damage

PURPOSE: To evaluate whether keratometric readings as a measure of corneal shape are associated with optic disc dimensions and with the degree and rate of perimetric progression of chronic open-angle glaucoma or ocular hypertension. METHODS: The hospital-based observational study included 1826 eyes of 936 patients with ocular hypertension, patients with chronic open-angle glaucoma, or normal individuals. For 733 ocular hypertensive or glaucomatous eyes, follow-up examinations were performed with a mean follow-up time of 58.0+/-34.7 months. Observation procedures were keratometry, morphometric optic disc analysis, tonometry, and perimetry. RESULTS: In the normal study group, area of the neuroretinal rim, alpha zone and beta zone of parapapillary atrophy, and retinal vessel diameter were not significantly associated with keratometric readings. In the entire study population, the optic disc area was significantly (P<0.001; r=-0.27) correlated with low keratometric readings as expressed in diopters. Keratometric readings were significantly (P<0.001 adjusted for age, intraocular pressure, baseline damage, and corneal asphericity) smaller in the normal-pressure glaucoma group than in the normal study group and in the groups with ocular hypertension or primary and secondary open-angle glaucoma. Rate of perimetric progression was not significantly associated with low keratometric readings, either in simple or in multiple Cox regression analysis, controlling for baseline damage, ocular hypertension, age, corneal asphericity, and intraocular pressure. CONCLUSIONS: Large optic disc area is statistically significantly, but clinically weakly, correlated with low keratometric readings (diopters). In Caucasian individuals with ocular hypertension and patients with chronic open-angle glaucoma, the rate of development or progression of glaucomatous visual field defects is not significantly associated with keratometric readings.     

Central corneal thickness correlated with glaucoma damage and rate of progression

PURPOSE: To evaluate whether the amount of glaucomatous optic nerve damage at presentation of the patient and the rate of progression of glaucoma during follow-up are related to central corneal thickness. METHODS: The prospective observational clinical study included 861 eyes of 454 white subjects (239 normal eyes of 121 subjects, 250 ocular hypertensive eyes of 118 patients, 372 eyes of 215 patients with chronic open-angle glaucoma). For 567 eyes (304 patients) with ocular hypertension or chronic open-angle glaucoma, follow-up examinations were performed, with a mean follow-up time of 62.7 +/- 33.2 months (median, 60.8; range, 6.2-124.9). All patients underwent qualitative and morphometric evaluation of color stereo optic disc photographs and white-on-white visual field examination. Central corneal thickness was measured by corneal pachymetry. RESULTS: Central corneal thickness correlated significantly (P < 0.001) and positively with the area of the neuroretinal rim and negatively with the loss of visual field. Development or progression of glaucomatous visual field defects detected in 119 (21.0%) eyes was statistically independent of central corneal thickness, in univariate (P = 0.99) and multivariate Cox regression analyses (P = 0.19). CONCLUSIONS: At the time of patient referral, the amount of glaucomatous optic nerve damage correlated significantly with a thin central cornea. Progression of glaucomatous optic nerve neuropathy was independent of central corneal thickness, suggesting that central corneal thickness may not play a major role in the pathogenesis of progressive glaucomatous optic nerve damage.     

Detecting early functional damage in glaucoma suspect and ocular hypertensive patients with the multifocal VEP technique

PURPOSE: To determine whether the multifocal visual evoked potential (mfVEP) technique can detect early functional damage in ocular hypertensive (OHT) and glaucoma suspect (GS) patients with normal standard achromatic automated perimetry (SAP) results. PATIENTS AND METHODS: Twenty-five GS patients (25 eyes), 25 patients with OHT (25 eyes), and 50 normal controls (50 eyes) were enrolled in this study. All GS, OHT and normal control eyes had normal SAP as defined by a pattern standard deviation and mean deviation within the 95% confidence interval and a glaucoma hemifield test within normal limits on the Humphrey visual field 24-2 program. Eyes with GS had optic disc changes consistent with glaucoma with or without raised intraocular pressure (IOP), and eyes with OHT showed no evidence of glaucomatous optic neuropathy and IOPs >or=22 mm Hg. Monocular mfVEPs were obtained from both eyes of each subject using a pattern-reversal dartboard array with 60 sectors. The entire display had a radius of 22.3 degrees. The mfVEPs, for each eye, were defined as abnormal when either the monocular or interocular probability plot had a cluster of 3 or more contiguous points with P<0.05 and at least 2 of these points with P<0.01. RESULTS: The mfVEP results were abnormal in 4% of the eyes from normal subjects. Abnormal mfVEPs were detected in 20% of the eyes of GS patients and 16% of the eyes of OHT patients. Significantly more mfVEP abnormalities were detected in GS patients than in normal controls. However, there was no significant difference in mfVEP results between OHT patients and normal controls. CONCLUSIONS: The mfVEP technique can detect visual field deficits in a minority of eyes with glaucomatous optic disks and normal SAP results.     

Suprathreshold static perimetry in glaucoma and other optic nerve disease.

Comparisons between automated suprathreshold static perimetry and manual kinetic perimetry were performed for 226 eyes with glaucoma or ocular hypertension, and 147 eyes with other optic nerve disease. Both techniques produced similar high detection rates for glaucomatous visual field defects, whereas suprathreshold static perimetry performed significantly better than kinetic testing in optic nerve disease other than glaucoma. It is concluded that automated suprathreshold static perimetry is an excellent quantitative screening technique for detecting visual field defects.