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At least 109 records · Page 6Linked to original sources
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↗
PubMed2003

Increased detection rate of glaucomatous visual field damage with locally condensed grids: a comparison between fundus-oriented perimetry and conventional visual field examination.

OBJECTIVE: To compare detection rates of glaucomatous visual field defects (VFDs) between the conventional 6 degrees x 6 degrees stimulus grid and locally condensed target arrangements in morphologically suspicious regions. METHODS: A total of 66 eyes of 66 patients with glaucoma or patients suspected of having glaucoma (34 females and 32 males; age range, 14-85 years) were enrolled in this study. Individual, local target condensation was realized by fundus-oriented perimetry (FOP) using a campimeter and compared with the results of conventional automated perimetry (CAP), obtained with the Humphrey Field Analyzer (30-2 grid). RESULTS: Twenty-three of the 66 patients showed normal findings with both methods; 27 had concordantly pathological results. In 15 patients we obtained normal findings with CAP, whereas FOP revealed early glaucomatous VFDs. Only one patient showed VFDs with CAP, whereas FOP results were normal. Scotoma detection rates significantly differed between the 2 methods (P<.001, sign test). Test duration with FOP was more than doubled compared with CAP. When considering only FOP points coinciding with the 6 degrees spacing of the 30-2 grid, there was no longer a significant difference between FOP and CAP (P>.25, sign test). This indicated that the target pattern, rather than the perimetric device, was most relevant for detecting glaucomatous VFDs. Follow-up throughout a series of 3 subsequent sessions at 6-month intervals revealed repeatable results in more than two thirds of all eyes for both FOP and CAP. CONCLUSIONS: Fundus-oriented perimetry that uses individually condensed test grids significantly increases the detection rate of glaucomatous VFDs in morphologically conspicuous areas compared with CAP using equidistant (6 degrees x 6 degrees) target arrangements. Repeatability is comparable between both methods.

Adolescent↗
PubMed2000

Electro-oculography, electroretinography, visual evoked potentials, and multifocal electroretinography in patients with vigabatrin-attributed visual field constriction.

PURPOSE: Symptomatic visual field constriction thought to be associated with vigabatrin has been reported. The current study investigated the visual fields and visual electrophysiology of eight patients with known vigabatrin-attributed visual field loss, three of whom were reported previously. Six of the patients were no longer receiving vigabatrin. METHODS: The central and peripheral fields were examined with the Humphrey Visual Field Analyzer. Full visual electrophysiology, including flash electroretinography (ERG), pattern electroretinography, multifocal ERG using the VERIS system, electro-oculography, and flash and pattern visual evoked potentials, was undertaken. RESULTS: Seven patients showed marked visual field constriction with some sparing of the temporal visual field. The eighth exhibited concentric constriction. Most electrophysiological responses were usually just within normal limits; two patients had subnormal Arden electro-oculography indices; and one patient showed an abnormally delayed photopic b wave. However, five patients showed delayed 30-Hz flicker b waves, and seven patients showed delayed oscillatory potentials. Multifocal ERG showed abnormalities that sometimes correlated with the visual field appearance and confirmed that the deficit occurs at the retinal level. CONCLUSION: Marked visual field constriction appears to be associated with vigabatrin therapy. The field defects and some electrophysiological abnormalities persist when vigabatrin therapy is withdrawn.

Adult↗
PubMedDate not supplied

The characteristics of static visual fields in children with psychogenic visual disturbances.

PURPOSE: It is well-known that patients with psychogenic visual disturbances (PVD) exhibit characteristic kinetic visual fields. Even when the kinetic fields are normalized, the static fields of PVD children frequently remain abnormal. To verify this finding, we performed static perimetry on those children whose kinetic fields were initially normal or which normalized during the follow-up period, and compared the results with those of children with psychosomatic disorders (PSD) and normal children. METHODS: We examined 9 PVD children (17 eyes), 16 PSD children (32 eyes), and 16 normal children (16 eyes). Program 30-2 or 24-2 of the Humphrey Field Analyzer was used in the examinations on all subjects. RESULTS: The average mean deviation (MD) of the PVD group was significantly lower than that of the other groups (P <. 01). False negative errors and short-term fluctuations were significantly higher in the PVD group than in the other groups (P <. 05). CONCLUSION: Although PVD and PSD children possess a similar underlying psychological dysfunction, their performances in visual field testing proved to be quite different. In the PVD group, even when kinetic fields were normal, functional visual field loss in the static fields was common and had characteristic response properties.

Child↗
PubMed2001

Rate of visual field loss and long-term visual outcome in primary open-angle glaucoma.

PURPOSE: To evaluate long-term visual field outcome in primary open-angle glaucoma. METHODS: In this retrospective cohort study, 40 eyes of 40 patients with primary open-angle glaucoma with elevated intraocular pressure and a minimum of 8-year longitudinal series of visual fields were plotted with Goldmann perimeter. Eyes with any other ocular disease except cataract were excluded. Manual grid templates were used to quantify the visual fields. Linear regression was performed to estimate the rate of visual field decline. Pertinent clinical factors were evaluated for statistical association with the rate of decline. Long-term clinical outcome including visual acuity, rate of legal blindness, and rate of medical and surgical interventions was also measured. RESULTS: In the 40 eyes studied, with a mean follow-up of 14 years, the visual field score decreased at the rate of -1.5% per year. Overall, 68% showed significant decrease, and the rate of decrease among these eyes was -2.1% per year. Five eyes became legally blind from glaucoma; the cumulative rate of blindness from glaucoma was 19% at 22 years. Higher intraocular pressure and greater number of antiglaucoma medications on initial presentation were associated with faster and slower deterioration of visual field (compared with the average), respectively. CONCLUSIONS: With standard glaucoma therapy, the rate of visual field loss in primary open-angle glaucoma is slow. Lower intraocular pressure and more antiglaucoma medications are associated with slower visual field decline. Legal blindness from glaucoma is 19% over a follow-up of 22 years.

Adult↗
PubMed1998

Glaucoma screening by optometrists: positive predictive value of visual field testing.

PURPOSE: Visual field testing is increasingly being performed by optometrists in order to improve glaucoma detection. The aim of this study was to assess the positive predictive value (PPV) of visual field testing as currently practised by optometrists. METHODS: A retrospective study was performed of referrals for suspected glaucoma to an ophthalmology department during a 3 month period. The PPV for glaucoma was determined according to the reason for referral. RESULTS: There were 86 referrals for suspected glaucoma. Isolated field loss accounted for 12% of these referrals but no cases of glaucoma detection. These subjects were either false positive referrals or had field defects of nonglaucomatous aetiology (tilted optic disc and porencephalic cyst). The PPV for glaucoma among referrals with isolated field loss was significantly less than that among referrals with field loss in association with corroborative abnormalities (0 vs. 60%, p = 0.005). No such difference was found for referrals with raised intraocular pressure (43% vs. 57%, p = 0.38) or suspicious discs (25% vs. 53%, p = 0.60). CONCLUSIONS: Visual field testing is currently leading to unnecessary referrals to the hospital eye service with no detectable improvement in the accuracy of glaucoma suspect referrals. It is important that optometrists perform visual field testing in accordance with validated screening methodology.

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↗