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Glaucoma: the value of a diurnal curve and Goldmann visual field.

A 35-year-old man was treated with maximum medical therapy for open-angle glaucoma. A diurnal curve revealed that the pressure was not controlled as might have been thought by a single reading. Reference is also made to the value of Goldmann visual field testing, since in this patient visual field defects were discovered with normal, healthy-appearing optic discs. A careful regimen including precise visual field testing and the plotting of the diurnal curve is most important in evaluating ocular hypertension and glaucoma.

Adult↗

[Effects of low-intensity laser irradiation on visual fields of patients with glaucoma].

Twenty-three patients (28 eyes) with open-angle glaucoma and controlled intraocular pressure were administered a course of He-Ne laser treatment. Irradiation parameters were as follows: wavelength 0.63 microns, light spot diameter 5 mm, energy 2 mWt, session duration 240 sec. A course consisted of 10 sessions. Seventeen eyes of the same patients were controls. Visual field was examined before the treatment and after it, immediately and in 3 to 3.5 months using Humphrey field analyzer and full field 120 points threshold related test. The treatment resulted in field deficit reduction by 10% and more in 21 (75%) of the 28 eyes. On an average, visual field deficit reduced by 22.4%. Three to 3.5 months after the treatment the mean value of visual field deficit was still lower than initially by 19.7%. No side effects were observed in any of the cases. In controls a trend to increase of field deficit developed within the same period, though the differences were statistically unreliable. The data indicate a positive effect of local low-energy laser exposure on visual field status of patients with primary open-angle glaucoma and controlled intraocular pressure.

Aged↗

Short wavelength automated perimetry, frequency doubling technology perimetry, and pattern electroretinography for prediction of progressive glaucomatous standard visual field defects.

PURPOSE: To evaluate the clinical use of a test battery of short wavelength automated perimetry (SWAP), frequency doubling technology perimetry (FDT), and pattern electroretinography (PERG) in predicting progressive glaucomatous visual field defects on standard automated perimetry (SAP). STUDY DESIGN: A prospective, longitudinal, observational case series. PARTICIPANTS: One hundred and fifty-two patients with primary open-angle glaucoma (POAG) with bilateral glaucomatous visual field defects on SAP were followed at 6-month intervals over a period of 30 months. MAIN OUTCOME MEASURES: Short wavelength automated perimetry, FDT, and PERG results were compared between POAG eyes with and without progressive field loss on SAP. These two groups were used to evaluate whether PERG, SWAP, and/or FDT is predictive of future progression of field loss on SAP. RESULTS: Using the criteria of progressive field loss on SAP defined by the Collaborative Normal Tension Glaucoma Study, 54 eyes (study group) of 54 POAG patients showed progressive defects, whereas 84 eyes (control group) of 84 POAG patients showed no progression. Only 11.1% (6 of 54) of the eyes with a progression of field loss on SAP showed no increase of deficits on the three functional tests before progression. Short wavelength automated perimetry detected early progressive defects on SAP in 43 of the 54 eyes (79.6%). Of these 54 POAG eyes, FDT showed progressive deficits in 40 eyes (74.1%), whereas PERG amplitude P1N2 showed progressive deficits in 35 eyes (64.8%) before progression of field loss on SAP. A test battery consisting of SWAP and PERG P1N2-amplitude was able to detect 88.9% of eyes before a prediction of field loss on SAP. When comparing the results of the two functional tests, SWAP and FDT in the 84 eyes without progression of field loss on SAP between baseline and at 30 months, SWAP and FDT showed progressive deficits in 34.5% and 35.7%, respectively. CONCLUSIONS: All three tests (SWAP, FDT, and PERG) have been successful in detecting glaucoma eyes with a future progression of standard visual field defects. A test battery of SWAP and PERG P1N2-amplitude improved the power to predict these progressive defects on SAP. It remains to be seen whether the long-term follow-up in POAG eyes will improve the false-positive rate of SWAP and FDT.

Disease Progression↗

Interpretation of visual field defects respecting the vertical meridian and not related to distinct chiasmal or postchiasmal lesions.

Hemianopia respecting the vertical meridian generally results from a disturbance in the optic chiasm or the postchiasmal visual pathway. We present five unusual patients with visual field defects respecting the vertical meridian that were not related to distinct chiasmal or postchiasmal lesions, as determined by magnetic resonance imaging (MRI). Optic neuritis, plus the influence of the testing algorithm for perimetry, was a possible cause in two cases. The symptoms of one patient with homonymous hemianopia were a functional deficit. In the two other cases, the visual field defects may have been caused by optic disc abnormalities. Although visual field defects respecting the vertical meridian, and without any evidence of distinct disease, are uncommon, neurologists and neuro-ophthalmologists should consider the differential diagnosis if MRI is negative for distinct lesions in the optic chiasm or the postchiasmal visual pathway.

Adult↗

[Relationship between corneal thickness and severity of visual field loss in primary open-angle glaucoma].

PURPOSE: To assess whether central corneal thickness is related to glaucomatous visual field loss severity among patients with office-controlled intraocular pressure in the normal range. METHODS: This transversal study included 85 eyes of 85 patients with treated primary open-angle glaucoma and documented intraocular pressure below 19 mmHg. The patients were divided into three groups according to Anderson criteria of field abnormality. The groups were composed of 30 eyes with mild defect, 28 eyes with moderate defect and 27 eyes with severe defect. Intraocular pressure and central cornea thickness were compared and evaluated between the three groups. RESULTS: Central corneal thickness was statistically thinner in the severe group (mean= 513 +/- 26 microm) compared with the mild defect group (mean= 535 +/- 35 microm) and the moderate group (mean= 533 +/- 30 microm) (p = 0.0182). There was no statistically significant difference between intraocular pressures in the three groups (p = 0.0851). The severe group showed a statistically higher age and number of medications than the other groups. CONCLUSIONS: The central corneal thickness measurement is desirable when establishing target intraocular pressure of patients with open-angle glaucoma. Central corneal thickness is a clinical factor in determining glaucoma severity. Patients with severe field loss showed lower corneal thickness compared with patients with mild and moderate visual field loss.

Aged↗

Linear vection in the central visual field facilitated by kinetic depth cues.

Illusory self-motion (vection) is thought to be determined by motion in the peripheral visual field, whereas stimulation of more central retinal areas results in object-motion perception. Recent data suggest that vection can be produced by stimulation of the central visual field provided it is configured as a more distant surface. In this study vection strength (tracking speed, onset latency, and the percentage of trials where vection was experienced) and the direction of self-motion produced by displays moving in the central visual field were investigated. Apparent depth, introduced by using kinetic occlusion information, influenced vection strength. Central displays perceived to be in the background elicited stronger vection than identical displays appearing in the foreground. Further, increasing the eccentricity of these displays from the central retina diminished vection strength. If the central and peripheral displays were moved in opposite directions, vection strength was unaffected, and the direction of vection was determined by motion of the central display on almost half of the trials when the centre was far. Near centres produced fewer centre-consistent responses. A complete understanding of linear vection requires that factors such as display size, retinal locus, and apparent depth plane are considered.

Adult↗

The rate of visual field loss in untreated primary open angle glaucoma.

The mean rate of visual field loss in untreated primary open angle glaucoma was estimated by comparing the mean age at presentation of patients with early relative visual field loss with the mean age of those who presented with absolute field loss within five degrees of fixation. Analysis of the records of 177 patients indicated that the rate of field loss was related to the level of untreated intraocular pressure. For pressures of 21 to 25 mm Hg, untreated disease is likely to progress from early field changes to end stage in an average of 14.4 years. The same interval for pressures of 25 to 30 mm Hg was 6.5 years and for pressures over 30 mm Hg, 2.9 years. For untreated disease at pressures over 25 mm Hg the interval is estimated at 3.6 years and this is much shorter than the estimated period of 10 years under imperfect treatment and 38 years under optimum treatment identified in a prospective clinical trial of early trabeculectomy in patients with similar intraocular pressures at diagnosis.

Adult↗

A screening method for chiasmal visual-field defects.

A strategy that selectively explores the vertical fixational meridian of the visual field was as sensitive as conventional quantitative Goldmann perimetry in detecting chiasmal hemianopic field defects, although it required only one quarter of the usual testing time. A trained but "masked" perimetrist, applying this abbreviated method to the examination of 28 eyes with hemianopic defects, 17 eyes with nerve-fiber defects, and 14 normal eyes, detected 100% of the hemianopias when using the Goldmann perimeter, 92% when using the conventional tangent screen, and 87% when using the projection tangent screen. False-positive diagnoses of hemianopic defects were 16%, 11%, and 14% on the respective instruments. While this strategy did not define the field defects fully, it accurately identified the features of diagnostic importance. By its efficiency, this approach may encourage greater use of visual fields as a determinant in managing the conditions of patients with unexplained visual loss.

Hemianopsia↗

Visual field influence on radial line bisection.

An attentional bias toward far peripersonal space has been proposed as the mechanism underlying inaccurate bisection of lines oriented radially in the sagittal plane. The position of stimuli in the visual scene has also been proposed as an important determinant of visual attention. This study was designed to evaluate the relative contributions of spatial and visual field factors in bisection of radial lines. The usual linkage of distant space and upper visual field was dissociated by assessing line bisection above eye level. Ten normal subjects bisected twelve 20-30-cm lines 35 cm above eye level and the identical stimuli 35 cm below the eyes. The previous findings of misbisection of radial lines distant to true center was replicated when stimuli were presented below eye level. Lines above eye level were misbisected significantly closer to the subjects. The findings suggest that visual field position influences the allocation of attention in the radial axis of space.

Adult↗

Effect of IOP on the visual field in ocuLar hypertension and glaucoma.

The traditional opinion that increased intraocular pressure is the cause of glaucoma is controversial, probably mainly because of the fact that firm evidence for the value of pressure reduction is largely lacking. The present article reviews results from short term studies of visual fields before and after pressure reduction. It also reviews published and unpublished preliminary results from studies addressing the problem of whether the long term visual field prognosis, in glaucoma and in ocular hypertension, is affected by pressure lowering therapy. There is no convincing agreement among results from modern studies using computerized perimetry indicating that acute lowering of the ocular tension results in an improvement of the glaucomatous visual field. Long-term result are equally conflicting, and often negative. We have noted from a preliminary analysis of our own masked, prospective study of patients with 'high risk' ocular hypertension, that the same results may be interpreted in quite different ways. The results of available studies certainly indicate that pressure reduction does not automatically lead to clear and positive effects on the visual field. The studies have often been small, however, and have usually not had the power of detecting small effects of treatment. Also, pressure reduction has usually not been dramatic and many treated patients have maintained 'elevated' pressure levels. Patients with very high pressures have not been included, and the effect of pressure reduction in this situation has therefore not been investigated at all. More controlled, prospective therapeutic studies are necessary and ethical. It seems particularly important to study the long-term effects of non-pharmacologically induced pressure reduction in patients with manifest field loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Glaucoma↗

Variability in patients with glaucomatous visual field damage is reduced using size V stimuli.

PURPOSE: To test the hypothesis that variability of conventional automated perimetry can be reduced using size V stimuli for patients with glaucomatous visual field damage. METHODS: Ten patients with glaucoma and five age-matched control volunteers were tested with the Humphrey Field Analyzer program 24-2 or 30-2, after which the method of constant stimuli was used to measure frequency-of-seeing curves. This was done by controlling the perimeter with a custom program run by a personal computer. At two widely separated visual field locations on the program 24-2 or 30-2 grid, stimuli were presented in 2 dB intervals to at least 10 dB on either side of the estimated program 24-2 or 30-2 threshold. This protocol was performed for each of three stimulus sizes (Goldmann sizes I, III, and V). For the patients with glaucoma, one test location was chosen in an area of normal visual field sensitivity, the other in an area of 10 to 20 dB loss. Control subjects were tested at the (3 degrees, 3 degrees) and (-21 degrees, -9 degrees) test locations. Fifteen repetitions were performed at each intensity. RESULTS: Repeated measures analysis of variance showed that variability, as measured by the standard deviation of the cumulative Gaussian function of the fitted frequency-of-seeing curves, was lowest at the abnormal sensitivity test location in the subjects with glaucoma using a size V stimulus. Differences between the results from the V to III and V to I stimuli were statistically significant (size V = 2.9 dB, III = 10.1 dB, I = 10.1 dB). The same trend in estimated standard deviations was present in tests of the area of normal sensitivity (size V = 1.1 dB, III = 1.7 dB, I = 2.0 dB) in subjects with glaucoma and for the control subjects' peripheral test locations, but not for the central location. The smaller reduction in variability between estimated standard deviations of the size I and size III stimuli was not statistically significant at any test location. CONCLUSIONS: Use of size V stimuli in conventional automated perimetry reduces variability in tests of moderately damaged and normal sensitivity test locations in subjects with glaucoma.

Analysis of Variance↗

Visual fields: simplified screening and recording procedures.

In some cases, visual field screening must be greatly simplified in order to obtain clinically useful information. This becomes possible when specific techniques are used for anomalies such as relative central scotoma, hemianopsia, and glaucomatous field defects. A working knowledge of visual pathway anatomy and function enables the optometrist to efficiently screen for these disorders by confrontation with red test objects, with pseudoisochromatic plates, and with the tangent screen. After the type of field defect has been determined by initial screening, recording its parameters with the tangent screen follows easily.

Color Perception Tests↗

Relationship of progression of visual field damage to postural changes in intraocular pressure in patients with normal-tension glaucoma.

PURPOSE: To evaluate whether postural changes of intraocular pressure (IOP) are associated with progression of visual field damage in patients with normal-tension glaucoma (NTG). DESIGN: Prospective, noncomparative, nonrandomized study. PARTICIPANTS: Sixty eyes of 33 patients with NTG. METHODS: Intraocular pressure, blood pressure (BP), and pulse rate (PR) were measured in both sitting and supine positions. Visual fields were examined using Humphrey Field Analyzer (HFA; Zeiss-Humphrey Instruments, Inc., San Leandro, CA). Changes in mean deviation (MD) per year (dB/year), that is, MD slope, were calculated by linear regression analysis of the HFA Statpac 2 program. MAIN OUTCOME MEASURES: The relationship between postural changes of IOP and MD slope was analyzed. The correlation between postural changes of IOP and cardiovascular parameters such as BP and PR also was analyzed. RESULTS: The IOP in the supine position was significantly higher than that in the sitting position (P<0.001, paired t test). There was no significant correlation between MD slope and sitting IOP (Pearson r = 0.172; P = 0.188), but a significant correlation was found between MD slope and supine IOP (r = -0.261; P = 0.043). The MD slope significantly correlated with IOP elevation caused by the postural change (r = -0.682; P<0.001). The systolic BP in the supine position correlated with postural changes of IOP (r = 0.364; P = 0.004), but other cardiovascular parameters did not correlate with IOP parameters. CONCLUSIONS: The progression of visual field damage in NTG is associated with IOP in the supine position and the magnitude of IOP elevation accompanying postural changes. These results suggest that deterioration in NTG may occur when patients are lying flat during sleep.

Aged↗

Right angular lesion and selective impairment of motion vision in left visual field.

A 45-year-old right-handed man had, for more than 20 years, a depressed fracture of the right parietal bone and selective impairment of movement vision in the left visual field; an illusory overestimation of speed of moving objects and extreme sensitivity to moving stimuli. Visuo-spatial perceptions of immobile objects, and other visual functions were normal apart from slightly decreased stereoacuity. The extent of depressed fracture corresponded approximately to the right angular gyrus. Carbamazepine or phenytoin did not alter the symptoms. After the operation, his symptoms were restricted to peripheral parts of the left visual field, with transient overestimation of speed of moving objects in the right hemifield. It was suggested that the human angular gyri may be involved in the central mechanisms of movement perception, and shift of visual attention or gaze to moving stimuli in contralateral visual field, especially in its peripheral part.

Humans↗

Radionecrosis of the inferior occipital lobes with altitudinal visual field loss after gamma knife radiosurgery.

A patient had bilateral superior altitudinal visual field defects because of radionecrosis of the inferior occipital lobes after gamma knife radiosurgery for a recurrent atypical cerebellar meningioma. Although radionecrosis of the anterior visual pathway has been well-documented, this is the first report of visual field loss associated with occipital lobe radionecrosis. The treatment dose this patient received is within the range of predicted tolerable radiosurgical dosing, although this patient was at increased risk for radionecrosis secondary to previous external beam radiotherapy. By offering an effective, noninvasive treatment, radiosurgery has changed the management of intracranial lesions. Radiosurgery targets a discrete volume of tissue and relatively spares the surrounding normal tissue. Radiation injury, or radionecrosis, is the only significant complication of radiosurgery (). We present a case of bilateral occipital lobe radionecrosis after gamma knife surgery that resulted in bilateral superior altitudinal defects.

Brain Diseases↗

Visual field constriction: accumulation of vigabatrin but not tiagabine in the retina.

BACKGROUND: The antiepileptic drug (AED) vigabatrin (VGB) causes concentric visual field constriction. Anecdotal reports involving tiagabine (TGB) have implied that this may be a class effect of all AEDs with gamma-aminobutyric acid (GABA)-related actions. We investigated the pharmacokinetic and pharmacodynamic profiles of VGB and TGB in rat brain and eye. METHODS: Adult male rats (n = 8) were administered 0.9% saline (control), VGB (500 or 1,000 mg/kg), or TGB (5, 10, or 20 mg/kg). At 1 (TGB) and 4 hours (VGB) postdosing, the animals were killed, a blood sample was obtained, their brains were dissected into five anatomic regions, and the retina and vitreous humor were isolated from each eye. Samples were analyzed for GABA concentrations and the activity of the enzyme GABA-transaminase (GABA-T). Plasma and tissue drug concentrations were also determined. RESULTS: VGB treatment produced a decrease in the activity of GABA-T and a rise in GABA concentrations in all tissues investigated. This effect was most pronounced in the retina. VGB concentrations were as much as fivefold higher in the retina than in the brain. TGB was without effect on GABA concentrations and activity of GABA-T. TGB concentrations were notably lower in the retina than in the brain. CONCLUSIONS: Accumulation of VGB in the retina, with or without an increase in GABA, may be responsible for the visual field constriction reported clinically. In contrast, TGB had no effect on GABA concentrations and did not accumulate in the retina. These results suggest that TGB is unlikely to cause visual field defects in humans.

Animals↗

The previous visual field: effects of lateralization and response accuracy on current performance.

The accuracy of performance in identifying syllables flashed to the RVF (right visual field) or LVF (left visual field) was strongly affected by the lateralization of and response accuracy for the previous stimulus, presented 10-20 sec earlier. For both the LVF and RVF, performance was better on Pre-LVF trials (previous stimulus in LVF) than on Pre-RVF trials (previous stimulus in RVF). The Pre-LVF advantage was the same in subjects with a strong RVF advantage and those with no asymmetry. Their performance was better when a previous stimulus had received adequate attention for correct encoding (Pre-Correct) than when it had not (Pre-Wrong), for both fields on Pre-LVF trials and the LVF, but not RVF, on Pre-RVF trials. Relations are discussed in terms of the capacities and properties of the RH (right hemisphere) and LH (left hemisphere) cerebral arousal systems.

Adult↗

Adaptation of the vestibulo-ocular reflex in albino rabbits by selective exposure of the anterior sector of the visual field.

Horizontal optokinetic reflexes (OKN) are inverted in an anterior (90-180 degrees) sector of the visual field in albino rabbits. We investigated whether the inverted processing of direction-selective information would affect long-term adaptation of the vestibulo-ocular reflex (VOR). Normal posterior parts of the visual fields were masked for periods up to 80 days. The inversion of OKN, with instability of the eyes and head in the light, was not corrected in this period. The amplitude of the VOR was progressively reduced, but a true inversion was not achieved. Recovery was seen after removal of the masks. These changes were larger and more consistent in Himalayan than in Polish rabbits. Normal, Dutch pigmented rabbits which served as controls showed no significant reduction of VOR gain. Phase lead of the VOR for low stimulus frequencies increased in both pigmented and albino rabbits. In short-term experiments with forced oscillation, similar but smaller changes were observed.

Animals↗