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PubMed1985

Automated differential threshold perimetry for detecting glaucomatous visual field loss.

Because early glaucomatous visual field defects occur asymmetrically across the horizontal meridian, we analyzed data from automated perimetry by comparing sums of threshold values of corresponding groups of points in the superior and inferior hemispheres of the central 30 degrees tested by the Humphrey Field Analyzer. We developed patterns and criteria from 25 early glaucomatous and 36 normal control eyes to achieve optimal balance between sensitivity (96%) and specificity (86%). Application of these criteria to an independent group of 27 glaucomatous and 105 control eyes yielded a sensitivity of 88.9% and specificity of 85.7%. Minor modification of the criteria improved sensitivity and specificity to more than 90% for both patients and controls.

Adult↗

PubMedDate not supplied

Visual field defect after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: To evaluate visual field defects after radial optic neurotomy (RON) in eyes with central retinal vein occlusion (CRVO). METHODS: Eight patients (eight eyes) underwent RON for macular edema associated with CRVO. Goldmann perimetry was performed on each patient both before and after surgery. RESULTS: Postoperative Goldmann perimetry showed a temporally located wedge-shaped visual field defect consistent with neural damage secondary to RON in seven eyes (88%). After surgery, the visual field decreased from preoperative values by 7% at 3 months (P = 0.30) and by 21% at 12 months (P = 0.0023). Although three patients (38%) were aware of the postoperative visual field defect, only one patient (13%) considered this defect to be a visual disability. CONCLUSIONS: After RON, most patients showed a postoperative defect in the temporal visual field consistent with the incision to the optic disk. However, this visual field defect appears to be well tolerated by most patients.

Adult↗

PubMed1978

Quantitative visual field and optic disc correlates early in glaucoma.

A retrospective study was made of persons with ocular hypertension and normal initial visual fields. Seventy eyes were followed, and glaucomatous visual field defects developed in 25 of these eyes. In eyes with ocular hypertensio, the area enclosed by the central visual field isopter (I2e) was significantly smaller than that previously reported for an age-corrected group of eyes with normal intraocular pressure. In the absence of glaucomatous visual field defects, isopter areas were not releated to cup-disc ratios. Coincident with visual field loss, reductions in both peripheral (I4e) and central (I2e) isopter areas correlated linearly with increases in the cup-disc ratio. Prior to visual field loss, the I4e isopter area wassignificantly smaller among those eyes destined to lose visual field.

Adult↗

PubMed1990

Optic disc and early glaucomatous visual field loss.

In the early stages of glaucoma, the disc changes prior to visual field loss, so assessment of the optic disc is very important for the evaluation of the glaucoma patient. The aim of this study is to assess the glaucomatous disc and to look for the features of the optic disc that are commonly associated with early visual field loss. Forty-three eyes of 28 patients were included in this investigation. The criteria for inclusion were a cup/disc(C/D) ratio of more than 0.4 by direct ophthalmoscopy, no visual field defect with Goldmann perimetry, and open anterior chamber angle. Each optic disc was photographed with a Canon fundus camera with Polaroid 600 Plus film. Each photographic set was then examined stereoscopically for morphologic parameters: 1) comparison of vertical versus horizontal C/D ratio; 2) presence of nasal cupping; 3) presence of overpassing vessels; 4) presence of baring of circumlinear vessels; 5) presence of peripapillary atrophy; 6) ratio of the thinnest neuroretinal rim(NRR) width in the vertical sectors of the NRR width of the temporal sector. All subject's central visual fields were examined with an automated static perimeter, Humphrey program C30-2 with STATPAC. The C/D ratio estimated by direct ophthalmoscopy consistently showed a smaller C/D ratio than that found by the stereophotographic method. The parameter with the highest probability value to differentiate between the optic disc of the early visual field loss and the optic disc of normal subjects was "Ratio of the thinnest NRR width in the vertical sectors to the NRR width of the temporal sector less than or equal to 85%". Although it has less resolving power than slide film, a stereo disc photograph with Polaroid film is a quick and simple method of recording changes, and the ratio of the thinnest NRR width in the vertical sectors to the temporal sector is a good predictive parameter for detection of early visual field loss.

Adolescent↗

PubMed2003

Measurement error of visual field tests in glaucoma.

AIM: Psychophysical strategies designed for clinical visual field testing produce rapid estimates of threshold with relatively few stimulus presentations and so represent a trade-off between test quality and efficiency. The aim of this study was to determine the measurement error of a staircase algorithm similar to full threshold with standard automated perimetry (SAP) and frequency doubling perimetry (FDP) in glaucoma patients. METHODS: Seven patients with early open angle glaucoma (OAG) were prospectively recruited. All were experienced in laboratory based psychophysics. Three matched test locations were examined with SAP (externally driven Humphrey field analyser) and FDP (CRT) in a single arbitrarily selected eye of each subject. Each location was tested twice with a 4-2-2 dB staircase strategy, similar to full threshold, and then with the method of constant stimuli (MOCS). Accuracy (threshold estimation error) was quantified by determination of differences between "true" threshold measurements made by MOCS and single staircase threshold estimates. Precision (repeatability) was quantified by the differences between repeated staircase threshold estimates. RESULTS: Precision was relatively high for both tests, although higher for FDP than SAP at depressed sensitivity levels. The staircase strategy significantly underestimated threshold sensitivity for both test types, with the mean difference (95% CI) between staircase and MOCS thresholds being 4.48 dB (2.35 to 7.32) and 1.35 dB (0.56 to 1.73) for SAP and FDP respectively. Agreement levels (weighted kappa) between MOCS and staircase thresholds were found to be 0.48 for SAP and 0.85 for FDP. Although this "bias" appeared constant for FDP across all sensitivity levels, this was not the case for SAP where accuracy decreased at lower sensitivity levels. CONCLUSION: Estimations of threshold sensitivity made using staircase strategies common to clinical visual field test instrumentation are associated with varying degrees of measurement error according to visual field test type and sensitivity. In particular, SAP significantly overestimates the "true" level of sensitivity, particularly in damaged areas of the visual field, suggesting that clinical data of this type should be interpreted with caution.

Aged↗

PubMed2003

Glaucomatous visual field defects in patients with migraine.

PURPOSE: To investigate the visual fields in patients with migraine in terms of glaucomatous visual field defects. METHOD: Patients who attended our Neurology outpatient clinic complaining of headache and were diagnosed as migraine were enrolled in the study. Each patient was questioned for the frequency, side, localisation and severeness of the pain as well as the onset and the duration of the symptoms, the existence of aura, the description of the aura - if present -, additional systemic problems, and family history of migraine and glaucoma. Detailed ophthalmological examinations and computerised visual field (VF) analysis were then performed on each patient in our Ophthalmology Clinic. The findings of 77 patients (61 female, 16 male) were evaluated and statistical comparisons were carried out between the group of patients with glaucomatous-like VF defects and the group without significant defects. RESULTS: VF tests revealed glaucomatous-like defects in 48 (62.3 %) patients. Intraocular pressure (IOP) levels were within normal limits in all cases. There were no statistically significant differences between the groups with and without VF defects in terms of sex, the localisation and severeness of pain, the existence and the description of aura, and family history of glaucoma, as well as the duration of migraine, IOP and cup/disc ratio. The glaucomatous group was significantly older, with a significantly higher age of onset for migraine. Risk of having glaucomatous-like defects was higher in patients who had migraine attacks once a month or less frequently. A tendency of pain and VF defects to develop ipsilaterally was noticed. DISCUSSION: A possible relationship between the pathophysiology of migraine, visual field defects and glaucomatous optic neuropathy is emphasized and VF screening for normal tension glaucoma is recommended in patients with migraine.

Adolescent↗

PubMed2004

Menstrual cycle dependent changes in blue-on-yellow visual field analysis of young diabetic women with severe non-proliferative diabetic retinopathy.

PURPOSE: To evaluate menstrual cycle dependent changes on blue-on-yellow visual fields of diabetic women, and to compare the results with those of healthy women. METHODS: Left eyes of 93 normally menstruating women were included in the study, comprising 45 with type-1 diabetes mellitus and severe non-proliferative diabetic retinopathy and 48 healthy controls. All subjects underwent baseline complete ocular examination and achromatic visual field analysis. Blue-on-yellow visual field tests (short-wavelength automated perimetry) were performed in both follicular (days 7-10 of the cycle) and luteal phases (days 3-6 before the bleeding) of two consecutive menstrual cycles. Visual field analyses were performed using Humphrey Field Analyser II with full threshold, central 30-2 program. Visual fields were divided into four regions: superior temporal, inferior temporal, superior nasal and inferior nasal. Visual field mean sensitivity (MS) was calculated for all regions separately. RESULTS: The mean ages of diabetic and control subjects were not significantly different (P > 0.05). Mean MS values of the diabetic group were significantly lower than that of the control group (P < 0.05). Control subjects did not demonstrate any menstrual cycle dependent changes in MS values (P > 0.05). However, diabetic women demonstrated a significant decrease in MS values in the luteal phase (P < 0.05). The decrease in MS was most marked in the nasal visual field (P < 0.05). CONCLUSION: Young diabetic women demonstrated a significant depression in visual field threshold sensitivity in the luteal phase of the menstrual cycle. Nasal visual fields are more prone to have menstrual cycle dependent threshold sensitivity depression. This should be taken into consideration in the clinical assessment of women with advanced diabetes who are at risk of glaucomatous optic neuropathy.

Adult↗

PubMedDate not supplied

Automobile driving performance of brain-injured patients with visual field defects.

The purpose of this study was to examine whether patients with visual field defects resulting from cerebral injury are handicapped in their driving ability, because visual field loss as assessed in standard perimetry is often the basis for withdrawal of a person's driving license. Driving performance was tested on a driving simulator to obtain standardized results and for safety reasons. The visual field was assessed both with standard automated perimetry and computer-based, high-resolution, qualitative perimetry. We investigated nine patients with purely cerebral field defects (mostly homonymous binocular defects) who had no further neuropsychological or ophthalmological deficits. Their performance (driving speed, reaction time, and driving error rate) was compared with that of a control group of ten subjects. We found no differences in any of the tested parameters between the visually impaired subjects and the normal participants. This suggests that individuals with visual field defects, including those who suffer from homonymous hemianopia, may perform as adequately as normal individuals in realistic driving scenarios. The perimetrically assessed visual field may, thus, be of limited value for the prediction of driving safety, and we conclude that patients who have field defects should not summarily be denied a driving license.

Adult↗

PubMed1997

Visual field constriction as a cause of blindness or visual impairment.

Reported are the results of a study of onchocerciasis in communities mesoendemic for savanna onchocerciasis in Kaduna State, northern Nigeria. The study involved 6831 individuals aged > or = 5 years who underwent an extensive screening examination for visual function including Friedmann field analysis. A total of 185 (2.7%) were bilaterally blind by acuity and an additional 28 (0.4%) were blind by visual field constriction. Also 118 (1.7%) individuals were visually impaired by acuity criteria. No criteria for visual impairment by field constriction have been established, and we therefore investigated three potential criteria. As a result, a further 60 (0.9%) individuals were identified with significant visual impairment due to field loss by the various definitions. Small islands of remaining peripheral field occurred in 50 individuals, while 40 individuals had marked reduction of binocular visual field below the horizontal meridian. Concentric visual field constriction to < 20 degrees was found in seven individuals. The WHO definition of blindness currently includes visual field damage criteria for blindness but not for visual impairment. Visual field loss is recognized as a major disability. We hope that these findings stimulate international discussion leading to the development of satisfactory definitions for visual impairment by visual field constriction.

Adolescent↗

PubMed1989

Visually perceived eye level and perceived elevation of objects: linearly additive influences from visual field pitch and from gravity.

Observing a pitched visual field (i.e. tilted around a horizontal axis in the observer's frontal plane) results in large changes in the elevation visually perceived to correspond to eye level (VPEL) and in the perceived elevation and size of stationary objects viewed against the field. With topforward pitch (top toward observer) VPEL lies above true eye level and objects appear smaller and lower; with topbackward pitch VPEL lies below true eye level and objects appear larger and higher. Oscillation of the pitched field induces synchronous perceived oscillation of elevation of a stationary target viewed against the field. Typical VPEL settings deviated from true eye level by 20 degrees with the field pitched at 40 degrees, although some individuals mislocalized by as much as 40 degrees. VPEL varied linearly with visual field pitch with individual slopes for the relation between VPEL and visual field pitch ranging from +0.42 to +0.78 (avg = +0.56). The linear correlation (r) between VPEL in darkness and against an erect visual field was +0.91. The two relations--VPEL vs visual field pitch, VPEL in darkness vs VPEL in the erect illuminated visual field (slope approximately equal to 0.5)--are both accurately predicted by the linear model: VPEL = kvV + kbB; in which V is the influence of visual field structure and B is the influence of the body-referenced mechanism which combines information regarding the orientation of the head relative to gravity, the position of the eye in the orbit, and the vertical location of the image on the retina; kv and kb are the relative weights of V and B with kv + kb = 1. In an illuminated field kv = kb approximately equal to 0.5; in the dark kv = 0, kb = 1.

Gravitation↗

PubMed2005

Lower visual field advantage for motion segmentation during high competition for selection.

A series of visual enumeration tasks were conducted investigating the role of the dorsal visual stream in motion segmentation. Cortical areas representing the lower visual field have greater connections with the parietal cortex and should therefore show an advantage for processes driven by the dorsal stream (Previc, 1990). We looked for differences in processing displays in the upper versus lower visual field when targets required segmentation from distractors in an enumeration task. In a baseline condition, random configurations of moving and static items were presented briefly (200 ms) to the upper or lower visual field. Fast and efficient enumeration took place both for moving targets and for static targets presented alone; there was no effect of visual field. In contrast, for moving targets, a lower visual field advantage was found when the inclusion of static distractors demanded segmentation by motion. This disappeared at the smaller display sizes when the targets were presented in canonical patterns. The results are consistent with segmentation of moving targets from static distractors being mediated by dorsal regions of the visual cortex, particularly under conditions of high load (non-canonical patterns). These regions show greater sensitivity to the lower visual field and to magnocellular-based input.

Attention↗

PubMed2001

[A study of Humphrey three zone screening to detect visual field of the patients with pituitary macroadenomas].

OBJECTIVE: To evaluate the clinical application of Humphrey three zone screening in detecting the visual field of the patients with pituitary macroadenomas (PMA). METHODS: There were two groups in the study. The PMA group: 128 PMA cases were selected who had symptoms of visual problem and been diagnosed with computer tomography (CT) or magnetic resonance (MR) and without apparent opacity of refractive medium. The low myopia group: thirty cases with low myopia and without other eye diseases were included. Humphrey three zone screening method was used to detect the 76-points in the central 30 degree visual fields of the patients of the two groups. RESULTS: In PMA group, 99.2% of the 128 patients and 87.1% of their eyes had visual field defect. 86.7% of the patients had the visual field defect mainly located at the temporal side and showed or tended to have a medial vertical limit. In detecting abnormality of the patients, three zone screening test had a sensitivity of 99.2% (percent of cases with true visual field defect identified by the field test). The mean test duration of each eye is (5.8 +/- 2.2) minutes. In low myopia group, two eyes of two patients had visual field defect. In testing the normal group, three zone screening test had a specificity of 93.3% (percent of cases without true visual field defect appropriately identified by the field test). CONCLUSION: Humphrey three zone screening has very high sensitivity and specificity in detecting visual field, and it is simple, fast and practical for detecting the visual field of the patients with PMA. It plays an important role in implying diagnosis and avoiding misdiagnosis of PMA.

Adenoma↗

PubMedDate not supplied

Normal isopter position in the peripheral visual field in goldmann kinetic perimetry.

PURPOSE: Often in young patients the question arises if a disease state has contracted their peripheral boundary of the visual field. Since the 'hill of vision' is steeper in the periphery, kinetic perimetry is more sensitive in detecting peripheral visual field abnormalities than static perimetry. In order to be able with kinetic perimetry to detect mild peripheral visual field constrictions, we determined the normal position of 4 isopters in the peripheral visual field. SUBJECTS AND METHODS: Intraindividual sensitivity variations of the isopters in the peripheral visual field were determined in 3 normal subjects by one perimetrist. Then, in 22 subjects (19-42 years old) the position of the isopters V4e, III4e, I4e and I3e has been determined by one perimetrist. Visual fields were registered using a Goldmann kinetic perimeter. RESULTS: The intraindividual sensitivity variations (measured as 1 standard deviation) for the isopter V4e was 0.98 degrees and for the isopter I4e 1.13 degrees. To visualize the normal isopter positions in the peripheral visual field, the average positions +/- 2 standard deviations were plotted for the isopters V4e, III4e, I4e and I3e. CONCLUSION: In this study, we determined the normal position of 4 isopters frequently used to plot the peripheral visual field. The plots have been printed in a scale of 1:4 in order to facilitate its use. Photocopying the figures on transparencies by scaling them with a factor 4 will allow to superpose the transparencies on individual Goldmann kinetic visual fields in order to easily determine whether the individual isopters are inside or outside the normal range.

Adult↗

PubMed1988

Evaluation of the t test as a method of detecting visual field changes.

Automated perimetry is used to monitor changes associated with many ocular conditions such as glaucoma, neuro-ophthalmologic disorders, and retinal diseases. Comparisons among sequential visual fields are crucial to the determination of progression or regression of ocular anomalies, and to evaluate the efficacy of various therapeutic regimens. The Delta program for the Octopus perimeter uses a t test to provide an objective comparison of visual fields. To evaluate the utility of the t test for detecting visual field changes, the authors used computer simulation to generate pairs of visual fields with known alterations, and made comparisons with the t test procedure used by the Delta program. An initial visual field based on normal data was produced and stored. A second visual field, based on the same normal data but with a scotoma of known size and depth, was also produced and stored. A t test (as used by the Delta program) was then used to compare the two visual fields for statistically significant differences. Our results indicate that the t test was very sensitive to small changes of the entire visual field, such as those produced by both pathologic and nonpathologic (day-to-day sensitivity variations, changes in pupil size, etc.) factors. However, the t test was unable to reliably detect small to moderate scotomata (less than or equal to 18 degrees in diameter), even when the sensitivity loss was greater than 35 dB. These findings suggest that the t test has limited clinical utility for objective detection of pathologic visual field loss, and that additional procedures may be necessary to provide reliable detection of visual field changes.

Adult↗

PubMed1990

Geometric optical investigation of the underwater visual field of aerial animals.

The underwater visual field distorted by refraction for aerial animals living near the water surface is investigated by means of geometric optics. The imaging of underwater objects by one and two aerial eyes is studied. The underwater binocular image field is determined for pairs of aerial eyes placed in horizontal and vertical planes. Some possible biooptical consequences of the visual detection of underwater prey and predator by aerial animals are discussed on the basis of the structure of their distorted visual field.

Animals↗

PubMed2005

Differences in visuomotor control between the upper and lower visual fields.

Danckert and Goodale [Exp Brain Res 137:303-308 (2001)] have shown that increases in movement time as target size decreased were greater when movements were performed in the lower compared with upper visual field. On this basis, they suggested that visual feedback processing was more effective in the lower visual field. However, despite the greater influence of target size on movement time for the lower compared to upper visual field, there were no differences in accuracy between visual fields for movements to the smallest targets. In the present study, we investigated whether superior performance would be observed in the lower visual field when movement times were constrained. Analysis of the variability in distance travelled at key kinematic markers (e.g. peak acceleration, peak velocity, and peak negative acceleration) revealed that limb trajectories were more consistent in the lower compared to upper visual field at the late stages of the movement. Also, squared correlation coefficients between the distance travelled at peak velocity and the distance at the end of the movement were smaller for movements performed in the lower visual field. These results imply that superior performance in the lower visual field was due to better utilization of visual feedback during movement execution.

Adolescent↗

PubMedDate not supplied

Visual field defects after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: Surgical decompression of the vein in central retinal vein occlusion (CRVO) by radial optic neurotomy (RON) was recently proposed as being surgically feasible, safe, and beneficial. The effect of RON on the visual field has not been systematically reported, although possible visual field defects are expected due to iatrogenic cutting of the optic nerve fibers. The authors report the results of visual field testing in patients who underwent RON at the Tel Aviv Medical Center. METHODS: Twelve consecutive patients (8 men, mean age of all patients 68 years) with nonperfused or indeterminate CRVO whose initial visual acuity (VA) was < or =20/400 underwent RON. Nine of these patients were able to perform visual field tests at 6 months post-RON and their visual field results are presented. RESULTS: : VA improved by > or =3 lines in 5 patients (42%). Three (25%) patients had a final VA of > or =20/200 and another had a final VA > or =20/50. Fundus and VA improvement were relatively slow. Two patients had clearing of the intraretinal blood, resolution of the venous dilation, and improved VA at the 2-month follow-up visit. Temporal visual field defects consisting of temporal ones that could be correlated to the site of the RON incision were detected in five out of the nine patients who were able to perform visual field tests. No temporal visual field defects were found in the remaining four patients, and three other patients were unable to perform visual field tests due to inability to identify the largest target size. CONCLUSION: VA improvement in 5 of 12 patients with ischemic or indeterminate CRVO following RON may be better than the natural history of CRVO. The risk of visual field defects may, however, be heightened by possibly cutting off blood supply to the optic nerve head and possible damage to nerve fibers in the optic nerve head, both inherent to the surgical procedure and both likely to produce visual loss.

Adult↗

PubMed1999

Visual field responses to a hand vibration stimulus.

Two short visual field tests were performed on 106 subjects approximately 5 minutes apart with or without a hand vibration stimulus between the field tests. There were 31 eyes in the control group (10 without glaucoma, eight glaucoma suspects, 10 with primary open-angle glaucoma, and three with secondary open-angle glaucoma). There were 75 eyes in the hand vibration group (16 without glaucoma, 20 glaucoma suspects, 25 with primary open-angle glaucoma, eight with secondary open-angle glaucoma, three with normal-tension glaucoma, and three with other forms of glaucoma). Average visual field sensitivities were significantly reduced in the arcuate zones after a hand vibration stimulus (-0.42 dB; SD, 1.26 dB) when compared with sensitivities in the arcuate zones in subjects without the hand vibration stimulus (+0.38 dB; SD, 1.53 dB; P = 0.01). Multivariate analysis demonstrated a significant reduction in this response in the arcuate zone associated with use of betaxolol (P = 0.021) and timolol (P = 0.047). Betaxolol was associated with significantly smaller reductions in visual field sensitivities in the paracentral zone (P = 0.01). Reductions in visual field sensitivities that may be related to ocular vasospasm occurred after a hand vibration stimulus. This response may be able to be modified pharmacologically with topical beta-blockers, particularly betaxolol.

Adolescent↗