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PubMed1992

Visual field loss in primary gaze and reading gaze due to acquired blepharoptosis and visual field improvement following ptosis surgery.

Acquired blepharoptosis has been associated with loss of the superior visual field (SVF) in primary gaze. Because many patients with acquired blepharoptosis complained of difficulty reading or performing other visual functions in reading gaze, a prospective study was undertaken to determine if acquired blepharoptosis was the cause of these visual dysfunctions. Preoperative and postoperative SVFs were tested in primary gaze and reading gaze in 19 patients with unilateral or bilateral acquired blepharoptosis totaling 30 eyes. Preoperative testing revealed a marked loss of the SVF in both primary gaze and reading gaze. All patients underwent levator aponeurosis defect repair. Postoperative results showed a significant improvement in both primary and reading gaze SVFs. Therefore, patients with good visual acuity complaining of difficulty reading or carrying out other visual functions in reading gaze should be examined for the presence of acquired blepharoptosis. Blepharoptosis repair can be expected to improve the SVF in both primary gaze and reading gaze.

Adult↗
PubMed1997

Visual impairment in Australia: distance visual acuity, near vision, and visual field findings of the Melbourne Visual Impairment Project.

PURPOSE: To describe the age-specific and gender-specific rates of blindness and visual impairment in urban adults aged 40 years and older. METHODS: A population-based sample of residents was recruited. Presenting and best-corrected distance visual acuities were assessed. Functional near vision was measured at each participant's preferred distance. Visual field examination was performed with a Humphrey Field Analyzer (HFA); those unable to perform the field analyzer test attempted a Bjerrum screen or confrontation field. RESULTS: The study population comprised 3,271 residents (83% of eligible) from ages 40 to 98 years; 54% were women. Overall, 56% of the study population wore distance correction; this was significantly lower in men but higher in the older age groups. Age-adjusted rates of blindness were 0.066% in men and 0.170% in women. Vision with current correction improved after refraction by gender and age. Direct age-standardized rates of functional near vision did not vary significantly by gender. Forty-six people had significant visual field loss in their better eye. The proportion of participants with constriction of the visual field to within 20 degrees of fixation was similar for men and women when controlled for age (odds ratio, 0.81; 95% confidence interval, 0.44 to 1.49) but increased significantly with age controlled for gender. Visual field abnormalities were detected in 548 right eyes (17%) and 533 left eyes (16%). CONCLUSIONS: Although overall rates of blindness because of visual acuity loss were relatively low, nearly three times more people had visual impairment because of visual field loss than visual acuity loss. These results highlight the need to target blindness prevention programs to the aging population, with a special emphasis on women.

Adult↗
PubMed1976

Visually evoked cortical potentials in the evaluation of homonymous and bitemporal visual field defects.

Visually evoked cortical potentials were studied in six patients with a homonymous and six with a bitemporal hemianopia by presenting a pattern-reversal stimulus separately to a temporal or nasal retinal area and by recording the responses from leads over the hemispheres. Homonymous visual field defects are characterized by a reduction of VECPs from the affected hemisphere. The disturbance of VECPs in bitemporal hemianopia is more serious, since the fibres from both retinal halves may be damaged by a chiasm tumour.

Evoked Potentials↗
PubMed1980

Giant aneurysms of the carotid system presenting as visual field defect.

Visual field loss was the presenting symptom in 19 patients with large intracranial aneurysms of the carotid system. Location of the aneurysm was cavernous, carotid-ophthalmic (two), supraclinoid (nine), anterior communicating (six). Other features were pain and a long history of fluctuating visual loss. Cavernous or carotid-ophthalmic aneurysms mostly caused purely uniocular field loss consistent with optic nerve compression. Supraclinoid aneurysms most often caused a lateral chiasmal syndrome. Anterior communicating aneurysms caused asymmetric compression of one or both optic nerves, the eye contralateral to the feeding artery being more often affected. Carotid ligation appeared to arrest visual deterioration in some patients in the supraclinoid group.

Adult↗
PubMed1997

Inter-observer and intra-observer agreement in the interpretation of visual fields in glaucoma.

Visual field changes are one of the main parameters used to monitor progression of glaucoma. This study assesses the degree of intra-observer and inter-observer agreement among nine observers in grading visual fields in glaucoma patients using a visual field system previously described by Jay. The results show a median inter-observer agreement of 61% (median kappa = 0.52) and a median intra-observer agreement of 72% (median kappa = 0.65). This system for grading fields in glaucoma has a high degree of intra-observer agreement, suggesting it is a useful system for longitudinal follow-up of patients by a single observer. The higher degree of disagreement between observers points to the need for careful pretraining of observers in clinical management and research where the results from visual field examinations are to be graded by more than one clinician.

Cohort Studies↗
PubMed1993

[Effect of systolic blood pressure on the location of visual field defects in upper and lower visual half-fields in patients with chronic simple glaucoma].

In earlier studies we found that visual field defects occur more frequently in the lower half of the visual field and that low systolic blood pressure occurs more frequently in low-tension glaucoma (stage II) compared to primary open-angle glaucoma (POAG) (stage II). We wanted to find out whether visual field defects in the lower half of the visual field point to insufficient perfusion of the optic nerve head due to low blood pressure. We therefore examined the visual fields of 153 eyes of 153 patients with POAG and regulated IOP with program 31 or 33 of the Octopus perimeter 201. With program Delta the loss per test point in the upper and lower hemifield was calculated. The mean systolic blood pressure was calculated for each patient from the blood pressure recordings during the observation time and over a long-term follow-up period (3-19 visual field examinations during a period of 1-8 years). With the Delta program we decided case by case whether the visual field showed a tendency to deteriorate or not. An asymmetry in the mean loss per test point between the two visual hemifields in a relation of 2:1 or more was found in 71 eyes out of 153. In the upper hemifield 50 out of 71 patients had two times greater loss per test point than in the lower hemifield. These patients showed a mean systolic blood pressure of 158 +/- 37 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The glaucoma suspect: differentiation of the future glaucoma eye from the non-glaucomatous suspect eye. 2. Visual field decay.

Visual-field areas to a I2e stimulus were measured planimetrically using an X-Y digitizer and a computer program. Sampling of normal subjects and patients suspected of having glaucoma was done at two points in time. Calculations of eye-wall stress were done using ultrasonic data and intra-ocular pressure (IOP) measurements from patient records. For those suspected of having glaucoma who developed chronic open-angle glaucoma (COAG), the time of transition was the second point in time. The visual field area was regressed against patient age at the two points in time. No difference in the regression slopes was found for the normal subjects and unchanged patients. The patients who did develop glaucoma were significantly different. The mean annual rate of visual-field change (rate of decay) was calculated and found to be 28.5 mm2/year for the normals, 153.5 mm2/year for the suspects, and 376.4 mm2/year for those patients who developed glaucoma. The rate of visual-field decay only correlated with patient age (P = 0.03) and eye-wall stress (P less than 0.01) in the patients who developed glaucoma.

Age Factors↗
PubMed1987

Functional properties of parietal visual neurons: radial organization of directionalities within the visual field.

Parietal visual neurons (PVNs) were studied in waking monkeys as they executed a simple fixation-detection task. Test visual stimuli of varied direction, speed, and extent were presented during the fixation period; these stimuli did not control behavior. Most PVNs subtend large, bilateral receptive fields and are exquisitely sensitive to stimulus motion and direction but insensitive to stimulus speed. The directional preferences of PVNs along meridians are opponently organized, with the preferred directions pointing either inward toward or outward away from the fixation point. Evidence presented in the preceding paper (Motter et al., 1987) indicates that opponent directionality along a single meridian is produced by a feed-forward inhibition of 20 degrees-30 degrees spatial extent. The observations fit a double-Gaussian model of superimposed but unequal excitatory and inhibitory receptive fields: When the former is larger, inward directionality results; when smaller, outward directionality results. We examine here the distribution of the meridional directional preferences in the visual field. Tests showed that opponent organization is not produced by differences in local directional properties in different parts of the receptive field. The distribution of response intensities from one meridian to another is adequately described by a sine wave function. These data indicate a best radial direction for each neuron with a broad distribution of response intensities over successive meridians. Thus, any single PVN, with rare exceptions, cannot signal radial stimulus direction precisely. We then determined how accurately the population response predicted radial stimulus direction by the application of a linear vector summation model. The resulting population vector varied from stimulus direction by an average of 9 degrees. Whether or not the perception of the direction of motion depends upon a population vector remains uncertain. PVNs are especially sensitive to object movement in the visual surround, particularly in the periphery of the visual field. This, combined with their large receptive fields and their wide but flat sensitivity to stimulus speed, makes them especially sensitive to optic flow. This is discussed in relation to the role of the parietal visual system in the visual guidance of projected movements of the arm and hand, in the guidance of locomotion, and in evoking the illusion of vection.

Action Potentials↗
PubMed1991

Visual field examination during transient migrainous visual loss.

A transient episode of bilateral amaurosis fugax, or transient visual loss, occurred in a patient with ophthalmic migraine associated with mitral valve prolapse while computerized visual field testing was performed. This fortunate finding illustrated characteristic defects which are compared with the patient's visual field tested 24 hours later. Statistical analysis of both examinations is stressed here.

Adult↗
PubMed1983

Pseudopapilloedema with and without verified optic disc drusen. A clinical analysis II: visual fields.

An analysis of visual field findings in the material of 200 patients with pseudopapilloedema with and without verified optic disc drusen was performed. Goldmann and/or Friedmann visual fields were examined in 383 eyes. Visual field defects were found in 38.9% of the pseudopapilloedema eyes without verified drusen, but in 73.4% of the drusen eyes. The strongest field defects were found only in the eyes with drusen seen by oblique illumination or with superficial drusen. The eyes with superficial drusen showed visual field defects in 85.8%. Only 7 patients complained of visual field defects. A progression of visual field defects could be documented in 22% of 118 patients with visual field examinations 2 or more times.

Adult↗
PubMed1986

The effect of protective sports eyewear on peripheral visual field and a peripheral visual performance task.

Seven different types of protective sports eyewear were tested to determine whether peripheral awareness as measured with a visual performance task were affected. Goldmann perimetry and the Wayne Saccadic Fixator with Stik-Up attachments were utilized in a repeated measures research design. The sports glasses did restrict visual field, but no one pair of glasses were least restrictive. The restrictions did not translate into significant differences on the performance task. Peripheral visual factors should be taken into account when prescribing protective sports eyewear. The importance of proper eye protection in sports is also discussed.

Adult↗
PubMed1993

Localization of objects in the peripheral visual field.

We investigated visual localization by asking humans to point at visual objects without vision of their hand. The objects were luminous discs, presented stereoscopically at different distances, eccentricities and meridians with respect to the subjects' straight-ahead. Final pointing position was recorded by an electromagnetic search-coil technique. We found that the eccentricity of pointing responses towards peripheral targets was larger when subjects fixated straight-ahead rather than looked at the targets. This outcome confirmed our previous finding that target eccentricity in the peripheral visual field is overestimated. We further found that overestimation increased less than proportionally with target eccentricity, which suggests that the local magnification factor gradually declines in the visual periphery. A quantitative analysis indicated that the magnification factor is about 1.5 at the fovea, and approaches 1.0 at 10 degrees visual angle. Thus, our data support the hypothesis of a peri-foveal magnification effect which gradually subsides with increasing eccentricity. The observed magnification was similar for the horizontal and the vertical meridian. We found that the egocentric distance of pointing responses depends not only on the distance of the object pointed at, but also on the distance of a second object in the visual field. This outcome was in quantitative agreement with the predictions of Foley's model of interactive distance evaluation. Response depth, i.e. the difference in the response distances towards the two objects, was larger if both objects appeared near the center of the visual field rather than if one object appeared in the visual periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Relationship cataract density and visual field damage.

In interpreting visual field results, two questions arise: a) what type of visual field damage is produced by cataract, and b) can the influence on the visual field somehow be predicted? To answer these questions, cataract density was quantified with the Opacity Lens Meter (OLM) 701, and visual field tests were done before and after IOL-implantation surgery with Octopus Program G1 in 58 eyes of 58 patients (mean age 71 +/- 8 years) with cataract but with no other detectable ocular diseases. The average improvement of mean damage (MD) after surgery was 5.4 dB, and that of D (20) (defect 20 on the Bebie Curve) was 5.7 dB. The improvement of the visual fields was, as expected, statistically highly significant (p < 0.0001). The corrected loss variance (CLV), however, increased on the average only by 2.5 dB2, which was not significant. The predictive value of the OLM reading for opacity-induced MD depends on the type of cataract. It is good for cortical and nuclear cataracts but poor for posterior subcapsular opacifications. The overall predictive value (R = 0.66) is, nevertheless, better than for preoperative visual acuity (R = -0.54). If OLM and visual acuity (VA) are considered together, the predictive value is slightly higher (R = 0.72). Thus, optical density influences on visual field performance can be subtracted from general visual field results.

Adult↗