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PubMed2005

Visual field defects and the risk of motor vehicle collisions among patients with glaucoma.

PURPOSE: To evaluate the association between visual field defects in the central 24 degrees field and the risk of motor vehicle collisions (MVCs) among patients with glaucoma. METHODS: A nested case-control study was conducted in patients with glaucoma aged 55 or more. Cases were patients who were involved in a police-reported motor vehicle collision (MVC) between January 1994 and June 2000; controls were those who had not experienced an MVC at the time of their selection. For each patient, an Advanced Glaucoma Intervention Study (AGIS) score was calculated on automated visual fields collected with the 24-2 or 3-2 programs. RESULTS: With respect to the better-eye AGIS score, compared with patients with no visual field defect, those with severe defects (scores 12-20) had an increased risk of an MVC (odds ratio [OR] 3.2, 95% CI 0.9-10.4), although the association was not statistically significant. Moderate (6-11) or minor field defects (1-5) in the better eye were not associated with the risk of involvement in a crash. In the worse eye, patients with moderate or severe field defects were at significantly increased risk of an MVC (OR 3.6, 95% CI 1.4-9.4 and OR 4.4, 95% CI 1.6-12.4, respectively) compared with those with no defects. Minor field defects in the worse eye did not increase risk of MVC (OR 1.3, 95% CI 0.5-3.4). CONCLUSIONS: Patients with glaucoma who have moderate or severe visual field impairment in the central 24 degrees radius field in the worse-functioning eye are at increased risk of involvement in a vehicle crash.

Accidents, Traffic↗
PubMed1985

Visual field rehabilitation in the cortically blind?

Investigators have recently reported that specific practice facilitates the restitution of visual fields in partially blinded humans with lesions to the striate cortex. In order to further evaluate this work, attempts were made to retrain twelve homonymous hemianopic or quadrantanopic patients with similar methods, but under conditions in which possible contaminating experimental variables were controlled, including: reliance on gross subjective impressions, large visual stimuli response variability, changes in detection strategies with practice and compensatory eccentric fixation. The results indicate that visual field increases are not trainable. It is concluded that previous studies should be regarded with caution and the restitution of visual fields after damage to the striate cortex in humans is probably not possible with existing methods.

Aged↗
PubMed2005

Increase in reaction time for the peripheral visual field during exercise above the ventilatory threshold.

The purpose of the present study was to determine whether reaction time (RT) for the peripheral visual field increases at exercise intensity above the ventilatory threshold (VT) during incremental exercise and to examine the relationship between aerobic capacity and the extent of increase in the RT. Nine healthy subjects performed a simple manual RT task for the peripheral visual field at rest, during exercise on a cycle ergometer, and immediately after exercise. After warm-up exercise, the subjects cycled at 40 W for 3 min, increasing by 40 W every 3 min until 240 W in a step-wise manner. During incremental exercise, RT measurements were performed 1 min and 30 s after the start of every increase in workload. The RT for the peripheral visual field significantly increased at exercise intensity above VT, as compared with at rest. The increase in the RT, which was calculated by subtracting the RT at rest from the RT at 240 W, negatively correlated with maximal oxygen uptake VO(2max) for each subject (r = -0.73, P < 0.05). It is likely that high aerobic capacity attenuates the increase in the RT for the peripheral visual field during exhaustive exercise.

Adult↗
PubMed2006

Visual field defects in epidemic dropsy.

UNLABELLED: Epidemic dropsy is a multi-system disease involving the cardiovascular, hepatic, renal, ocular and other systems. It is a toxic disease caused by the unintentional ingestion of Argemone mexicana (prickly yellow poppy) seeds as an adulterant of wheat flour or more commonly of cooking oil such as mustard oil. PURPOSE: To investigate the occurrence of visual field defects in patients suffering from epidemic dropsy glaucoma. METHODS: Visual field analysis was performed to ascertain the field defects, in patients suffering from epidemic dropsy. Group I consisted of 35 patients (69 eyes) whose intraocular pressure (IOP) was > or = 22 mmHg. Ten dropsy patients (20 eyes) with normal IOP (<22 mm Hg) formed Group II. Ten healthy unexposed volunteers (20 eyes) constituted Group III. All the patients were tested using the Armaly full field glaucoma screening test on the Humphrey field analyzer. RESULTS: Forty seven of the 69 eyes (68%) suffering from epidemic dropsy glaucoma, and 18 out of 20 (90%) eyes in dropsy patients with normal IOP, showed field defects. In the control group, 15% eyes had only nasal field defects. The difference between Group I and II was not significant (p = 0.054), though the field defects were significantly more frequent in dropsy patients as compared to the controls (p < 0.01 in either case). The results suggest that visual field defects in epidemic dropsy occur independently of the rise in intraocular pressure. Field defects were detected more frequently in patients who underwent visual field analysis early in the course of disease, as compared to those who underwent screening later on in the disease course. CONCLUSIONS: In epidemic dropsy, acute visual field defects occur independent of rise of intraocular pressure and more frequently in the early stage of the disease.

Adolescent↗
PubMed2000

[Study on the progression of visual field defect and clinical factors in normal-tension glaucoma].

PURPOSE: We investigated the relationship between the progression of visual field defect and clinical factors in patients with normal-tension glaucoma (NTG). SUBJECTS AND METHODS: Forty-eight eyes of 48 NTG patients undergoing more than 5-year follow-up were enrolled in this study. Their visual field defects ranged between Aulhorn's classification stage 2 and 4, and mean deviation (MD) more than -10 dB measured by Humphrey Field Analyzer (HFA). End points of this follow-up study were defined as follows: in HFA STATPAC 2 glaucoma change probability analysis, more than 5 points which significantly deteriorated at p < 0.05 were found at 2 consecutive examinations (Criterion 1) or a significant decrease in MD value at p < 0.025 was encountered at one examination or in MD value at p < 0.05 at consecutive examinations (Criterion 2). RESULTS: During the follow-up period, 18 eyes of 48 patients satisfied Criterion 1 and 21 eyes Criterion 2. There were no significant differences in clinical factors between patients with progression and without progression. By multiple logistic regression analysis, minimum flow velocity of central retinal artery (CRA) showed significant relation (odds ratio for a 1 cm/sec rise = 0.2215; 95% confidence interval: 0.0530-0.9253) to progression of visual field defect in Criterion 1, and minimum flow velocity of CRA (odds ratio for a 1 cm/sec rise = 0.2099; 95% confidence interval: 0.0506-0.8712) and cholesterol (odds ratio for a 1 cm/dl rise = 1.0332; 95% confidence interval: 0.4096-2.6064) showed significant relation in Criterion 2. CONCLUSION: These results suggests that vascular risk factors of ocular blood flow may play a role in the progression of visual field defects in NTG patients.

Adult↗
PubMed1990

Influence of lens opacities on visual field indices.

This report presents the results of a study designed to verify the influence of lens opacities on the visual field indices. Four age-matched groups of subjects were considered: healthy volunteers, glaucomatous patients without lens opacities, cataractous patients without glaucoma and glaucomatous patients with lens opacities. The quantification of lens opacities was performed with the Lens Opacity Meter 701 instrument. The visual field indices were obtained automatically from the G1 program of the Octopus system. The statistical analysis of the results (coefficient of correlation) has shown that only the visual field indices that correspond to uniform and diffuse loss of light sensitivity were influenced by the presence of cataract. On the contrary, the visual field indices that indicate local irregularities of the threshold were not significantly influenced by the presence of lens opacities.

Aged↗
PubMed1983

JO and STATJO: programs for investigating the visual field with the Octopus automatic perimeter.

In evaluating the effectiveness of glaucoma therapy the visual field is the most important consideration. Comparison of visual fields is difficult, however, and only large changes are detectable with the methods of manual perimetry currently used. Two programs created for use with the Octopus automatic perimeter are described in this paper. One of the programs, called JO, is sensitive to small changes in threshold; the other, called STATJO, calculates means and converts the results to a form suitable for statistical evaluation.

Computers↗
PubMed1992

Visual field differences in an object decision task.

Two experiments are reported which investigate hemispheric processing in an object decision task. Experiment 1 used 40 pictures of objects, and 40 pictures of nonobjects, and subjects decided manually whether each lateralized stimulus represented an object. Results indicated an interaction between visual field and response (yes versus no). There was a right visual field advantage for positive responses, but no difference between visual field for negative responses. Positive responses were faster than negative responses, and this effect was more marked for right visual field presentations. These results were replicated in a second experiment. The results are interpreted as reflecting a left hemisphere superiority at accessing stored structural descriptions of known objects. The possibility that left and right hemispheres use different methods of carrying out the task is also discussed.

Adult↗
PubMed1997

Early detection of visual field progression in glaucoma: a comparison of PROGRESSOR and STATPAC 2.

AIM: To compare the performance of PROGRESSOR (pointwise linear regression) and STATPAC 2 (comparison with baseline values) in detecting early deterioration in the visual fields of glaucoma patients. METHODS: Visual field series from 19 untreated normal tension glaucoma eyes which were deteriorating on clinical grounds were analysed by PROGRESSOR and STATPAC 2. Progression criteria for PROGRESSOR were (1) inner points: slope < -1 dB/year, p < 0.05 and (2) edge points: slope < -2 dB/year, p < 0.05. Criteria for STATPAC 2 were p < 0.05 change probability for any point on three consecutive fields. Detection time was defined as the time interval between the initial field and the first field in which at least one progressing point was identified. Detection times produced by the two techniques were compared. RESULTS: PROGRESSOR and STATPAC 2 agreed on progression in all 19 eyes. Mean detection time for PROGRESSOR was 1.077 (SD 0.985) years and for STATPAC 2 was 2.161 (1.357) years. PROGRESSOR detected progression sooner than STATPAC 2 in 18 eyes (p < 0.01), Wilcoxon matched pairs signed rank test). PROGRESSOR detected progression earlier by a mean of 1.085 (0.936) years. CONCLUSIONS: PROGRESSOR consistently detected progression earlier than STATPAC 2. The PROGRESSOR software is a useful tool for the early detection of visual field deterioration in glaucoma.

Algorithms↗
PubMed2004

Timing of interactions across the visual field in the human cortex.

While it is generally believed that interactions across long distances in the visual field occur only in the higher-order cortical areas, other results suggest that such interactions are processed very early. In the preceding paper, we identified the latencies within a subset of cortical areas in the human visual system. In the present study, we test in which areas and at which latencies the responses to two visual patterns start interacting. We used functional magnetic resonance imaging directly combined with visual-evoked potential source analysis. Interactions appeared first anterolaterally to the retinotopic areas, at 80 ms for two stimuli presented in the left lower visual quadrant and at 100 ms for symmetrical stimulation of both lower quadrants. In the lateral occipital-V5 region (LOV5), two patterns presented simultaneously in one quadrant elicited a response with shorter latency and infra-linear addition of the amplitudes compared with the patterns presented separately. For bilateral stimulation, the timing of the LOV5 response coincided with the response to contralateral stimulation alone. Other visual areas showed interactions appearing later than within LOV5: starting at 150 ms in V1, at 120 ms in V3-V3a for the left visual hemifield stimulation and at 160 ms for both visual hemifields stimulation. Our data show that distinct patterns in the visual field interact first in LOV5, suggesting that this region must be the first to pool spatial information across the whole visual field.

Adult↗
PubMed1978

Primary empty sella syndrome with panhypopituitarism, diabetes insipidus, and visual field defects.

A 58 year old woman with a history of hypothyroidism was evaluated for marked visual impairment and found to have the primary empty sella syndrome with multiple endocrine abnormalities. Visual field determination revealed preservation of vision only in the left inferior quadrants bilaterally. Failure of growth hormone (hGH), cortisol and prolactin to respond to insulin induced hypoglycaemia (0.1 U/kg), of luteinizing hormone (LH) and follicle stimulating hormone (FSH) to respond to gonadotrophin releasing hormone (GnRH, 100 microgram) and of thyrotrophin (TSH) and prolactin to increase after thyrotrophin releasing hormone (TRH, 500 microgram), confirmed the diagnosis of panhypopituitarism. Following water deprivation with a 9% loss in body weight, her urine osmolality remained at 204 mOsm./kg H2O), indicating that she had posterior pituitary deficiency as well. During surgical exploration, which was performed in an effort to improve her markedly impaired vision, a compromised vascular supply to the left optic nerve and chronic arachnoiditis was demonstrated. This case represents one extreme of functional impairment in a syndrome which is generally considered benign and which rarely requires therapeutic intervention. Our patient is compared to 29 reported cases of the primary empty sella syndrome with visual field defects. The operative findings in eight of these cases are reviewed. The need for a multidisciplinary approach and close follow-up of patients with an empty sella and functional deficits is emphasized. Surgical intervention including lysis of adhesions and chiasmapexy has been effective in selected cases in reversing or stabilizing visual field abnormalities.

Adolescent↗
PubMed1991

Instruction effects on gender differences in visual field advantages during lexical decision tasks.

Two experiments explored the effects of speed, accuracy, on speed and accuracy instructions on visual field advantages to lexical decisions in males and females. In Experiment 1, right visual field advantages in reaction time appeared in the groups of males in the accuracy condition and in the speed and accuracy condition. In Experiment 2, feedback consistent with the instructions was given to subjects. Females and males in the accuracy condition showed a right visual field advantage in the second block of trials. These findings suggest that cognitive variables mediate right visual field advantages to lexical decisions in males and females.

Adult↗
PubMed1993

The effect of simulated cataract on the glaucomatous visual field.

PURPOSE: The current study is designed to determine the effect of light scattering (simulated cataract) on glaucomatous visual fields. METHODS: Twelve patients with relative scotomas caused by glaucoma underwent the 30-2 threshold test with the Humphrey Visual Field Analyzer twice: once with and once without having a light-diffusing piece of ground glass in front of the eye, which, in previous experiments, has been shown to decrease perimetric threshold by 4.4 decibels (dB) in normal eyes. As controls, 12 patients underwent the same examination with and without a piece of clear glass in front of the eye. In each pair of fields, five points were analyzed within the relative scotoma and compared with five points in a normal area of the opposite hemifield. RESULTS: The diffusing ground glass produced a mean decrease of perimetric threshold of 5.7 dB (standard deviation [SD] = 3.3 dB) within the area of relative scotoma compared with 6.1 dB (SD = 2.4 dB) within the normal area and 4.4 dB (SD = 2.25 dB) at the fovea. The differences between means were not statistically significant. In addition, the diffusing glass did not affect the corrected pattern SD (CPSD) index (6.5 dB with the diffuser and 6.5 dB without). CONCLUSION: Light scattering depresses the glaucomatous visual field diffusely. Relative glaucomatous scotomas and normal areas are depressed equally, expressed as change in decibel of sensitivity. Therefore, in following patients with cataracts and glaucoma, depression of threshold sensitivity in glaucomatous areas out of proportion to normal areas should not be attributed to the light-scattering effect of the cataract, but rather to possible worsening of glaucomatous damage.

Aged↗
PubMed1995

The Glaucoma Laser Trial (GLT): 6. Treatment group differences in visual field changes. Glaucoma Laser Trial Research Group.

PURPOSE: To determine the differences in visual fields during 42 months (3 1/2 years) of follow-up between eyes treated with argon laser trabeculoplasty first and eyes treated with topical medication first in patients with newly diagnosed primary open-angle glaucoma. METHODS: Visual field examinations were obtained at enrollment, three and six months, and at six-month intervals thereafter during follow-up of 271 patients enrolled in the Glaucoma Laser Trial. Numeric analyses of the examination results, including global indices and patterns of localized changes, as well as masked subjective clinical impression, were used to compare the two treatment groups. RESULTS: The mean threshold for eyes treated with laser trabeculoplasty first was 0.3 dB better than that for eyes treated with topical medication first averaged over follow-up (95% confidence interval, [-0.1, 0.7]; P = .17). More eyes treated with topical medication first (82 [31%] of 261 eyes) than eyes treated with laser trabeculoplasty first (61 [23%] of 261 eyes) had confirmed localized deterioration at least once during follow-up (P = .02). Improvement was nearly twice as common as deterioration on masked subjective impression in both groups through 30 months (2 1/2 years). Eyes treated with laser trabeculoplasty first were judged to have slightly more improvement and slightly less deterioration than eyes treated with topical medication first. CONCLUSION: During follow-up, measures of visual field status for eyes treated with laser trabeculoplasty first were slightly better than those for eyes treated with topical medication first. Statistical significance was attained for only some of the differences, and the clinical implications of such small differences are not known.

Adult↗
PubMed2000

Association of presbyopic correction with changes in visual fields.

The purpose of this study was to investigate the effect of presbyopic correction on changes in visual fields caused by an alteration in outflow of aqueous humour Visual fields were compared before and after introduction of presbyopic correction in participants of the Melbourne Visual Impairment Project. Height and slope of the 'Hill of Vision' were assessed by calculating median thresholds in the four sets of three eccentric points. Analysis of 101 eyes in the study group and 101 eyes in the control group shows higher decrease of the 'Hill of Vision' height in the group of participants who started wearing presbyopic correction, than in the group without presbyopic correction (P = 0.02). Intraocular pressure measured irrespectively of participant's accommodative activity was not significantly different between the two groups at both time points. These data suggest that the use of presbyopic correction is associated with changes in the visual field.

Accommodation, Ocular↗
PubMed1998

Lateral dynamic balance reactions to circular translation of the visual field.

Lateral sway of subjects in spontaneous dynamic balance conditions on a seesaw platform was measured during a visual stimulation monocularly produced by a rotating glass covered with a prism membrane. Prism rotation induced the perception of a circular translation of the whole visual field and an ocular pursuit movement. Therefore, the retinal slip that occurs in normal pursuit was cancelled. Strong stereotyped postural reactions were observed in a direction that depended upon both the vertical visual field deviation and the eye stimulated: upper position of the right visual field induced a leftward sway resulting from an extension of the right hemibody; symmetrical reactions occurred for the left stimulation. The results suggest that the postural reactions recorded depend on the isolated oculomotor activity and, in addition, on retinal afferences corresponding to the temporal crescent of the stimulated side, which orientates the postural reaction on the homolateral lower limb muscles.

Eye Movements↗
PubMedDate not supplied

Pituitary atrophy in Korean (epidemic) hemorrhagic fever: CT correlation with pituitary function and visual field.

Eleven patients with Korean (epidemic) hemorrhagic fever were each studied three times with high-resolution CT in order to demonstrate necrosis of the pituitary gland and to correlate the CT findings with the patients' pituitary function and visual fields. Seven of the 11 patients showed varying degrees of progressive decrease in the height of the pituitary gland: one severe, two moderate, and four mild. The visual fields of all the patients were checked at the time of the third (last) follow-up CT. Six of the 11 patients had bitemporal superior quadrantanopsia. In five patients, the decreased height (atrophic change) of the pituitary gland and the visual-field defect were coincidental. The visual-field defects in those patients were not improved on follow-up examination 5 weeks later. Two patients in whom a 1-year follow-up examination was performed showed no interval changes in the defects. Pituitary function tests were performed in nine of the 11 patients (six with atrophic pituitary glands and three without atrophic changes) at the time of the third CT. Five of the six patients with atrophy showed decreased pituitary reserve function for follicle-stimulating hormone, cortisol, or human growth hormone, while only one patient showed decreased reserve function for cortisol among the three patients without atrophic change. The pituitary atrophic changes observed on follow-up sellar CT are thought to be the result of the ischemic necrosis of the gland. The high probability (five of seven) of visual-field defects in those patients with atrophic glands suggests optochiasmatic and pituitary ischemia as the basic pathogenesis.

Adult↗