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At least 1,189 records · Page 66Linked to original sources

PubMed2003

Relationship between intraocular pressure and preservation of visual field in glaucoma.

Intraocular pressure (IOP) correlates with progressive loss of visual field in patients with glaucoma. Decreasing IOP has been proven to reduce progressive loss of the visual field. This is true both for glaucoma patients with IOPs above or within the normal range. For individuals with ocular hypertension (high IOP but no evidence of glaucomatous neuropathy), lowering IOP may reduce the risk of developing glaucoma. This article reviews scientific evidence that supports the importance of lowering IOP in patients with glaucoma or ocular hypertension.

Glaucoma↗

PubMed1988

Screening for glaucomatous visual field defects: the relationship between sensitivity, specificity and the number of test locations.

The visual field results from 104 eyes with early glaucomatous loss and 1860 normal eyes have been used to derive the relationship between sensitivity, specificity and the number of test locations in a visual field screening test. A logarithmic relationship was found between sensitivity and the number of test locations and a linear relationship between specificity and the number of test locations. The results indicate that large numbers of test locations are not required to reach high levels of sensitivity and that clinically it might be better to screen all patients with a few stimuli quickly than to examine carefully those patients who meet a precondition such as raised intraocular pressure or abnormal disc appearance.

Computers↗

PubMed1999

Parapapillary atrophy in patients with focal visual field loss.

PURPOSE: To examine parapapillary atrophy in normal subjects and patients with primary open-angle glaucoma with focal visual field loss. METHODS: Twenty-nine patients with repeatable early focal visual field loss according to standard automated perimetry (Humphrey program 24-2) and 29 matched (age and disk area) normal subjects were included. Parapapillary atrophy area and optic disk topography were evaluated with a confocal scanning laser ophthalmoscope. The difference in parapapillary atrophy area between normal subjects and patients with glaucoma was examined. Optic disk topography was evaluated by means of the rim-disk area ratio in 36 10-degree sectors and classified into diffuse and focal patterns of neuroretinal rim thinning. In patients with a focal pattern, the locations of rim thinning and parapapillary beta zone atrophy were compared. RESULTS: Beta zone atrophy was detected more frequently in patients with glaucoma (45% [13/29]) than in normal subjects (7% [2/29]), and it was located both superiorly and inferiorly in 92% (12/13) of the glaucoma patients. Alpha zone atrophy was significantly larger in patients with glaucoma than normal subjects (P = .009) but not more frequent (97% [28/29] in both groups). Sixty-one percent (8/13) of glaucoma patients with beta atrophy had diffuse thinning and 31% (4/13) had focal thinning. Eight percent (1/13) did not have neuroretinal rim thinning. In the four patients with both focal rim thinning and beta zone atrophy, the location of rim thinning corresponded to the location of the beta zone atrophy (100% [4/4]). CONCLUSIONS: In patients with early focal glaucomatous visual field loss, the presence and location of parapapillary beta zone atrophy and neuroretinal rim thinning are in good correspondence. Observation of localized parapapillary beta zone atrophy in clinical practice should direct one to more closely examine the optic disk in this region, as it may reveal localized rim thinning in a disk previously considered to be normal. Moreover, diffuse structural change in an eye with only focal functional change, as determined by standard automated perimetry, is consistent with the possibility that structural damage may be more widespread than functional damage in these patients.

Adult↗

PubMed1991

Visual field asymmetries for pattern processing are present in infancy. A comment on T. Hatta's study on children's performances.

From a study on 4 to 6 year-old children, Hatta (Hatta, Neuropyschologia 28, 1053-1062, 1990) concludes that (a) a left visual-field advantage develops at age 4 to 5 years in visuo-spatial stimulus recognition, and (b) since both the right visual-field advantage for verbal and the left visual-field advantage for visuo-spatial material develop at the same age, there is no support for the claim that the left and right hemispheres develop differentially. We contest these conclusions on the basis of our own infant studies which have shown a right visual-field advantage in 4 to 9 month-old infants for individual face recognition and more recently, for some aspects of visual patterns.

Child, Preschool↗

PubMed1992

[Sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment; a case report].

A case of sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment is reported. A 73-year-old woman visited our hospital with the complaint of head heaviness on the 27th of March, 1989. Although results of neurological examinations were normal, craniogram revealed the destruction of the clivus, and CT scan and MRI showed a mass lesion, which was thought to be a mucocele in the sphenoid sinus. On the 1st of September, she developed right abducens nerve palsy and visual field impairment. MRI performed on the same day showed an enlargement of the mass lesion in the sphenoid sinus. In order to decompress the involved cranial nerves, her sphenoid sinus was explored on the 22nd of September. The sphenoid sinus was filled with purulent fluid and yellowish mass. Histopathological examination revealed colonies of aspergillus fumigatus. Fluconazole, a new antifungal drug, was given for 34 days postoperatively. The right abducens nerve palsy and the visual field impairment gradually improved along with a reduction of the mass lesion in her sphenoid sinus. Sphenoid sinus aspergillosis is a rare disease. Its diagnosis is difficult. However, MRI can show a specific low signal intensity in T2-weighted image. Also in our case, MRI on the first admission showed a definite low signal intensity in some parts of the lesion, which exhibited a high intensity later on during the second administration, probably due to a qualitative change. To our knowledge, only 33 such cases have been previously reported. Intracranial involvement occasionally occurs in this disease. In its early stage, cranial nerve palsies are caused by nerve compression or invasion by this disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Abducens Nerve↗

PubMedDate not supplied

Imageability and word recognition in the left and right visual fields: a signal detection analysis.

Identifying the information processing constraints that determine whether or not imagery moderates visual field asymmetries is essential for constructing a dynamic model of hemispheric interaction during language processing. In this investigation, we manipulated the global experimental context in which imageable and nonimageable words were presented by contrasting mixed and blocked word lists using a lateralized lexical decision task. Signal detection analyses were employed to assess whether global stimulus context and imageability differentially affect word discriminability (d prime) and response bias (log beta) across visual fields. Both discriminability and response bias varied with imageability and stimulus context, but to a comparable extent across visual fields. This suggests that both hemispheres are sensitive to the global context in which words are presented, and can adjust processing based not only on semantic characteristics of the words themselves, but also on the variability of items in the stimulus environment.

Cognition↗

PubMed1995

Correlation of pattern discrimination perimetry to the optic disc and visual field in ocular hypertensive and chronic open-angle glaucoma patients.

We evaluated 19 ocular hypertensive and 32 chronic open-angle glaucoma patients to determine the correlation of pattern discrimination field loss to known markers of glaucomatous damage on the visual field and the optic nerve head. This study found no statistical association of the findings on the pattern discrimination perimeter to the areas of the optic disc, peripapillary halo, peripapillary atrophy, neural rim, or cup/pallor discrepancy (P > 0.05). In addition, no statistical relationship was observed to the diameters of the largest vein or artery in the inferior- or superior-temporal quadrant adjacent to the optic disc (P > 0.05). Between pattern discrimination and automated perimetry no agreement was observed in any visual field cluster (Glaucoma Hemifield Test) greater than that expected by chance alone (P > 0.05). When both visual function tests disagreed, the proportion of abnormal diagnoses in any cluster did not differ statistically between tests in chronic open-angle glaucoma patients (P > 0.05). However, in ocular hypertensive patients a greater proportion of abnormal diagnoses was observed with pattern discrimination perimetry (P < 0.03). This study suggests that pattern discrimination perimetry appears to measure a different physiologic property of the retina than does automated perimetry.

Adult↗

PubMed2001

Senescent changes of the normal visual field: an age-old problem.

PURPOSE: To examine the effect of normal aging on visual field sensitivity and identify the best-fitting function for normal populations. METHODS: Full Threshold standard automated perimetry data (program 24-2, Humphrey Field Analyzer) was collated retrospectively from clinically normal subjects who had previously been recruited for studies of normal visual function. One eye of each subject was randomly selected for analysis. Linear, bilinear, and simple nonlinear candidate functions of mean sensitivity vs. age (independent variable) were applied to these cross-sectional population data. Differences in the aging effect by eccentricity and hemifield were also considered. RESULTS: Data from 562 normal eyes were available for analysis. A significant negative relationship existed between age and mean visual field sensitivity within the cross-sectional population data. Coefficients of determination for the linear, bilinear, and nonlinear functions were 0.21, 0.20, and 0.26, respectively, indicating that the nonlinear function provided best characterization of the effect of age on mean sensitivity. A small but significant increase in the aging effect was present both peripherally (p < 0.001) and superiorly (p < 0.001). DISCUSSION: The nonlinear function that provided the best fit to cross-sectional population data indicates that age exerts an increasing effect on perimetric sensitivity with age, which has implications for clinical devices that use linear age coefficients to correct for normal aging effects. A linear age correction will overestimate aging changes for younger subjects and, therefore, may miss early pathologic changes in visual sensitivity. Conversely, linear age correction will also underestimate aging changes for older subjects and, thus, may overcall pathological sensitivity loss in this group. The effect of age within subjects requires further investigation to provide reliable estimates of the effect of age on sensitivity.

Adolescent↗

PubMed2001

A double masked placebo controlled study on the effect of nifedipine on optic nerve blood flow and visual field function in patients with open angle glaucoma.

AIMS: To investigate whether nifedipine affects ocular perfusion or visual fields in open angle glaucoma patients. METHODS: In a parallel group study nifedipine or placebo was administered for 3 months (n = 30). Ocular fundus pulsation amplitude (FPA), cup blood flow (Flowcup) and visual field mean deviation (MD) were measured. RESULTS: Five patients receiving nifedipine discontinued due to adverse events. Nifedipine did not affect FPA [difference: 0.3 microm (95% CI -0.3,0.9); P = 0.70], Flowcup: [difference: -9 rel.units (95% CI -133,114); P = 0.99], or MD [difference: 0.2dB (95% CI -2.2,2.7); P = 0.51] vs placebo. CONCLUSIONS: Systemic nifedipine is not well tolerated in glaucoma patients and exerts no effect on visual fields or ocular perfusion.

Administration, Oral↗

PubMed2000

Visual field plasticity in a female with right occipital cortical dysplasia.

Brain plasticity refers to its ability to recover after damage. Visual field plasticity is not well recognized. We report a 12-year-old female who first presented with recurrent seizures and was subsequently found to have a large, right occipital cortical dysplasia on magnetic resonance imaging. Her visual field by Goldmann perimetry was totally normal. Visual-evoked potential studies revealed the left hemifield P100 response was detected maximally at the right temporal and parietal regions. A weak but reproducible right hemifield P100 response was located at the right medial skull base. Functional magnetic resonance imaging with flashlight stimulation revealed cerebral activity mainly at the right posterior temporal and parietal lobes and left occipital lobe. These studies suggested that the left hemifield function was located at the right posterior temporal and parietal lobes. The left occipital lobe may also have been reorganized, with a P100 vector pointing out from its inferiomedial base. We reviewed other related reported cases. We believe that visual-evoked potential studies and visual functional magnetic resonance imaging should be performed more liberally for recognition of visual field plasticity.

Brain Mapping↗

PubMed1993

Computer-assisted interpretation of resolution visual fields from patients with chiasmal and retrochiasmal lesions.

Computer-assisted interpretation of resolution visual fields was performed in 147 normal subjects and 174 consecutive patients with known chiasmal or retrochiasmal lesion. The program identified 99% of normal subjects, and provided support for the correct diagnosis in 64% of patients with chiasmal and 83% of patients with retrochiasmal lesions. In conclusion, computer-assisted interpretation of resolution visual fields can provide considerable support to the final diagnostic decision in patients with lesions of the visual pathways.

Adolescent↗

PubMed1991

Quadrantic visual field defects. A hallmark of lesions in extrastriate (V2/V3) cortex.

We report 2 patients with homonymous quadrantic visual field defects. The first patient experienced scintillations in the left lower quadrant, leading to the discovery of an astrocytoma in the cuneus of the right occipital lobe. Postoperatively she had a left lower quadrantanopia that precisely respected the horizontal meridian. The second patient presented with a left lower quadrantanopia, sparing the central 10 degrees of vision that also respected the horizontal meridian. An astrocytoma was resected from the right upper peristriate cortex. We must explain how a lesion in extrastriate cortex produced a homonymous field defect with a sharp horizontal edge in these 2 patients. Areas V2 and V3 are each divided along the horizontal meridian into separate halves flanking striate cortex. Consequently, the upper and lower quadrants in extrastriate cortex are physically isolated on opposite sides of striate cortex. We propose that a lesion involving V2/V3 may be sufficient to create a visual field defect. Although the lesion may have irregular margins, if it crosses the representation of the horizontal meridian in extrastriate cortex, it will produce a quadrantic visual field defect with a sharp horizontal border because of the split layout of the upper and lower quadrants in V2/V3.

Adult↗

PubMed1993

Intraocular pressure and visual field decay in chronic glaucoma.

A total of 41 eyes of 28 patients with primary open-angle glaucoma and low-tension glaucoma (group 1) were followed for 12-72 months with tonometry and automated perimetry. A second group consisting of 13 eyes (9 patients) with secondary glaucoma (pigment dispersion, goniodysgenesis, ciliolenticular block and chronic angle closure) was followed for 13-60 months. None of the eyes had undergone filtering surgery during the follow-up period. The visual field decay was calculated by means of regression analysis of the mean defect. There was a significant correlation between visual field decay and both mean intraocular pressure (IOP, P > 95%) and maximal IOP (P > 98%) in the secondary glaucomas, which was not found in group 1. IOP oscillation expressed by the standard deviation of IOP was significantly correlated with progressive visual field loss in both groups. The slope of visual field decay was independent of the functional damage at the initial examination. Even if the influence of IOP level on the course of primary chronic glaucoma may have been masked by other factors that have a great interindividual variation, the oscillation of IOP seems to be at least as important as the level of IOP.

Adult↗

PubMed2003

Association between lower optic nerve laser Doppler blood volume measurements and glaucomatous visual field progression.

AIM: To perform a preliminary assessment of the relation between optic nerve circulatory parameters and glaucomatous visual field progression. METHODS: This study included 29 eyes of 23 patients with open angle glaucoma that had typical glaucomatous nerve fibre bundle visual field defects and increased cup to disc ratios. Laser Doppler flowmetry (Oculix) was used to measure relative optic nerve blood volume (Vol), velocity (Vel) and flow in the superior temporal (ST) and inferior temporal (IT) neuroretinal rim of the optic nerve. After blood flow measurements patients were followed for 6-62 months (mean 33 (SD 17) months) and 2-11 Humphrey visual fields (4.7 (2.6) fields) were obtained. Progression of glaucoma was assessed by the slope of the corrected pattern standard deviation (CPSD) values versus time, which was calculated manually for each eye using regression analysis. RESULTS: A significant negative correlation was observed between Vol in the IT rim and the CPSD slope (r=-0.56, p=0.002); patients with lower Vol tended to show faster progression of glaucomatous field damage than those with higher Vol. When the eyes were arbitrarily divided into two groups according to lower Vol (0.32 (0.06) arbitrary units, AU, n=15) or higher Vol (0.49 (0.06) AU, n=14), those with lower Vol had significantly worse mean CPSD slopes (0.50 (0.48) dB/year) than those with higher Vol (-0.67 (1.38) dB/year; Student's t test, p=0.009). CONCLUSIONS: In the IT rim, the area most prone to develop glaucomatous field damage, lower Vol is associated with subsequently faster CPSD progression. These measurements suggest that circulatory abnormalities may have a role in the development of glaucoma.

Adult↗

PubMed2003

Measuring visual field progression in the Early Manifest Glaucoma Trial.

AIMS: The Early Manifest Glaucoma Trial (EMGT) (316 eligible eyes) has used a new set of criteria to define visual field progression in glaucoma. This paper provides estimates of the amount of visual field worsening required to reach the EMGT definition of definite perimetric progression. METHODS: In the 148 eyes that reached definite progression, we first determined changes between baseline and the time of definite EMGT progression, both for mean deviation (MD) and for number of highly (p < 0.5%) significantly depressed test points in pattern deviation probability maps. Second, we studied whether such changes depended on baseline MD, intraocular pressure (IOP), age and time to progression, all of which are factors that affect the rate of field progression. RESULTS: In eyes reaching progression, the mean change in MD from baseline was -1.93 dB (SE +/- 0.20) and the mean change in number of significant points was +4.85 (SE +/- 0.35). These changes did not show linear dependency on baseline MD, IOP or time to progression. CONCLUSIONS: The average amount of field deterioration needed to reach EMGT visual field progression has been measured and expressed in more conventional units (i.e. a loss of about - 2dB in MD and an increase in about five highly significant points). These estimates will facilitate the clinical interpretation of the results of EMGT.

Aged↗

PubMed2005

Comparison of retinal nerve fibre layer thickness and visual field loss between different glaucoma groups.

BACKGROUND/AIMS: Scanning laser polarimetry (SLP) uses a confocal scanning laser ophthalmoscope with an integrated polarimeter to evaluate the thickness of the retinal nerve fibre layer (RNFL). The aim of this study was to verify the ability of the SLP to detect differences in RNFL thickness between normal and glaucomatous eyes and between glaucomatous eyes subdivided in groups by the severity of visual field damage. METHODS: This was a cross sectional retrospective study. The charts of 40 healthy subjects and 68 glaucoma patients who underwent complete ophthalmological examination, optic disc stereophotography, peripapillary, and macular SLP imaging were reviewed. The right eye of subjects eligible for the study was enrolled. Only eyes with SLP examinations indicating a minimised effect of anterior segment birefringence based on macular image were included. The ability of retardation parameters to discriminate between healthy and glaucomatous eyes was evaluated. Based on visual field loss, glaucoma patients were subdivided in three subgroups (early, moderate, and severe). RNFL thickness between healthy control group and glaucoma subgroups was compared. RNFL thickness and visual field loss correlation was evaluated. RESULTS: There was a significant difference in superior and inferior maximum RNFL thickness between normal and glaucomatous eyes (p<0.001). With these two parameters, the area under receiver operator characteristic curve was 0.75 and 0.74, respectively. Superior and inferior RNFL thickness was significantly different between healthy control group and all glaucoma subgroups (p<0.001) and between glaucoma subgroups (p<0.05), except for early and moderate glaucoma subgroups (p>0.05). Linear regression showed a weak correlation between RNFL thickness and visual field loss. CONCLUSION: These results suggest that once visual field loss is established, smaller reductions in the RNFL thickness detected by SLP are necessary for a given reduction of mean defect value.

Adult↗

PubMed1989

The relation between head and apparent visual field motion in the pigeon (Columba livia).

In order to study the relationship between the apparent motion of the visual field as a function of head motion, we have developed an equation that describes the apparent displacement of objects in the visual field produced by a general movement of the head consisting of a rotation plus a translation. We then used this equation to simulate the apparent motion of the visual field of a pigeon produced by rotation of the head about axes parallel to those of its anterior semicircular canals.

Animals↗

PubMed1990

Detection of early visual field change in ocular hypertension using STATPAC.

Perimetric tests were performed on 32 ocular hypertensive eyes (17 patients) with the C-30-2 threshold program of the Humphrey Visual Field Analyzer. The global indices of 32 ocular hypertensive eyes were compared with those of 34 normal eyes (17 controls). None of the 34 normal eyes had visual field sensitivity loss. However, three out of 32 ocular hypertensive eyes, which is 0.4%, had visual field sensitivity loss. Of these three eyes, two eyes showed generalized depression (MD, P less than 5%) and one eye showed paracentral scotoma.

Adolescent↗