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PubMed1992

Weighting according to location in computer-assisted glaucoma visual field analysis.

In recent years several aids for automated interpretation of visual field data have been suggested. We believed that incorporation of thorough knowledge of normal visual field variability would allow improvements in the performance of such aids since more attention would be paid to field results in areas with low physiological variability. Two visual field models for classification of fields in glaucoma based on comparisons of sensitivity values in the upper and lower hemifields and on analysis of test point clusters with diminished sensitivity were compared. Both models were constructed using logistic regression analysis in 101 normal eyes and 101 eyes with glaucoma. The first, more traditional model assumed Gaussian distributions of deviations from age-corrected normal thresholds and constant variability across the field (non-weighted model). The second model took into account empirically determined variability of pointwise threshold results and of cluster volumes in various visual field regions (weighted model). The two models were subsequently tested on an independent material of 163 normal eyes and 76 eyes with glaucoma. The weighted model gave significantly better classification of the fields in both materials. Accounting for physiological threshold variability can offer significant advantages in the construction of perimetric analysis aids for detection of glaucoma.

Adult↗

PubMed2003

Hartmann-Shack technique and refraction across the horizontal visual field.

We compared refractions across the horizontal visual field, based on different analyses of wave aberration obtained with a Hartmann-Shack instrument. The wave aberrations had been determined for 6-mm-diameter pupils up to at least the sixth Zernike order in five normal subjects [J. Opt. Soc. Am. A 19, 2180 (2002)]. The polynomials were converted into refractions based on 6-mm pupils and second-order Zernike aberrations (6 mm/2nd order), 3-mm pupils and second-order aberrations (3 mm/2nd order), 1-mm pupils and second-order aberrations (1 mm/2nd order), and 6-mm pupils with both second- and fourth-order aberrations (6 mm/4th order). The 3-mm/2nd-order and 6-mm/2nd-order refractions differed by as much as 0.9 D in mean sphere on axis, but the differences reduced markedly toward the edges of the visual field. The cylindrical differences between these two analyses were small at the center of the visual field (<0.3 D) but increased into the periphery to be greater than 1.0 D for some subjects. Much smaller differences in mean sphere and cylinder were found when 3-mm/2nd-order refractions and either the 1-mm/2nd-order refractions or the 6-mm/4th-order refractions were compared. The results suggest that, for determining refractions based on wave aberration data with large pupils, similar results occur by either restricting the analysis to second-order Zernike aberrations with a smaller pupil such as 3 mm or using both second- and fourth-order Zernike aberrations. Since subjective refraction is largely independent of the pupil size under photopic conditions, objective refractions based on either of these analyses may be the most useful.

Adult↗

PubMed2000

Vigabatrin-associated visual field defects in children.

PURPOSE: Vigabatrin (Sabril), a drug that blocks GABA transaminase, has been used in the treatment of epilepsy since 1989. There have been reports of irreversible constriction of the visual field in adult patients related to vigabatrin (VGB) therapy, resulting in reduced VGB usage in adults. Although used as a second or third line agent in adults, in children it is often considered as a first line treatment for several subgroups of seizures in spite of there being no way, in the majority of cases, to monitor visual fields. Some of these children have a pre-existing visual field defect as part of their primary disorder. We aimed to identify whether visual field loss due to VGB was occurring in our hospital. METHODS: We have studied the results of ophthalmic examination in 14 children on VGB at Great Ormond Street Hospital who were able to perform Goldmann visual fields. RESULTS: Ten of the 14 patients had constriction of their visual fields attributed to VGB. In addition there were 2 patients with suspicious visual field defects thought to be due to VGB. There was pre-existing visual pathway damage in 4 cases and in 2 of these optic disc pallor increased in association with constricted visual fields. However, the optic discs were normal in 7 patients in spite of visual field constriction. Visual acuity was generally normal in spite of gross visual field constriction. CONCLUSIONS: We believe that VGB should be used with great caution where there is pre-existing visual pathway damage. In other cases the benefits should be considered in relation to the risks, which include irreversible visual field damage. At present visual fields can only be monitored by perimetry, which is often not possible in children with epilepsy.

Adolescent↗

PubMed2002

Validity of a new disk grading scale for estimating glaucomatous damage: correlation with visual field damage.

PURPOSE: To determine the correlation of a new disk grading system, the disk damage likelihood scale (DDLS), with the visual field damage in patients with glaucoma. DESIGN: Observational case series. METHODS: Charts of 75 patients (150 eyes) with primary open-angle glaucoma (POAG), 41 patients (82 eyes) with low-tension glaucoma (LTG), and 25 patients (50 eyes) with pseudoexfoliative glaucoma (PXFG) were reviewed retrospectively. DDLS stages and vertical disk sizes were recorded. A masked observer staged the Humphrey field analyzer (program 24-2) visual fields using the Hodapp-Parrish-Anderson (HPA) visual field staging system. Mean deviation (MD) and pattern standard deviation (PSD) values were obtained. The correlation of DDLS with the visual field parameters and HPA staging system were evaluated. Findings were assessed by the Pearson and Spearman correlation coefficients. RESULTS: In the 282 eyes studied, the DDLS was strongly correlated with both MD (Pearson r = - 0.695, P <.001) and PSD (Pearson r =.703, P <.001). The HPA visual field staging system was also strongly correlated with the DDLS (Spearman r =.711, P <.001). These relationships continued to be significant when the three diagnostic groups (POAG, LTG, PXFG) were evaluated separately (P <.001) and also for small (< 1.5 mm) and average size (1.5-2.0 mm) disks. Large disks (> 2.0 mm) were not evaluated, because there was an insufficient number of cases. CONCLUSION: DDLS, a new system for estimating glaucomatous disk damage, strongly correlates with the degree of glaucomatous visual field damage.

Adult↗

PubMed1983

Quantitation of glaucomatous visual field defects with the Mark II Friedmann analyzer.

To evaluate the ability of the Friedmann visual field analyzer to determine visual threshold and the depth of visual field defects, we correlated the visual threshold determined kinetically (Goldmann perimeter) with the static threshold (Friedmann analyzer) in various parts of the central field. We found the following: the Friedmann working threshold correlated linearly with the height of the hill of vision represented by the position of the kinetic isopters of the Goldmann perimeter; the static visual threshold (Friedmann) at a particular location, whether normal or abnormal, was linearly related to the kinetic visual threshold (Goldmann) at that location; and the depth of all visual field defects was essentially the same with both instruments. Thus, the Friedmann analyzer accurately quantitated the central visual field in both the normal and abnormal regions, and may be advantageous for following the progress of early glaucomatous defects. For other patients, however, its usefulness may be limited, because defects outside 25 degrees cannot be documented, the visual field examination may be lengthy and inefficient when quantitating large defects of irregular depth, and the maximal quantitation of depth with the Friedmann analyzer is 2.0 log units less than with the Goldmann perimeter near fixation (but there is progressively less difference for defects further from fixation).

Aged↗

PubMed1998

Word repetition within- and across-visual fields: an event-related potential study.

A divided visual field (DVF) procedure was used to investigate the scalp distribution of the event-related potential (ERP) repetition effect. ERPs were recorded from 27 scalp sites whilst subjects (n = 20) discriminated between words and non-words presented to either the left (LVF) or the right (RVF) visual field. A proportion of the words were repeated on the trial immediately following their first presentation. In two within-field repetition conditions the two encounters with a word occurred in the same visual field (LVF or RVF). In two across-field repetition conditions, the two encounters with a word occurred in different visual fields. For both words and non-words, task performance was better for RVF presentations than for LVF presentations. In each repetition condition there was a positive-going shift in the ERP elicited by repeated words compared to that elicited by words on their first presentation. This ERP repetition effect was equivalent in magnitude and lateralised to the right hemisphere to an equivalent degree in all four repetition conditions. It is suggested that the ERP effects largely reflect the processing of visual form thought to occur predominately in the right hemisphere.

Adolescent↗

PubMed1996

Visual field loss following vitreous surgery.

OBJECTIVE: To assess possible causes of visual field loss following vitreous surgery. DESIGN: Charts of 8 patients prospectively identified, who developed visual field loss following vitreous surgery, were reviewed to characterize this newly recognized syndrome and assess possible causes. RESULTS: Two patients had preexisting chronic open-angle glaucoma and 1 had ocular hypertension. Indications for surgery included 4 eyes with macular holes, 1 eye with epiretinal membrane, 2 eyes with rhegmatogenous retinal detachment, and 1 eye with retinal detachment and giant retinal tear. All patients received retrobulbar anesthesia. Seven of 8 patients had fluid/gas exchange with installation of long-acting bubbles. In 1 patient with a macular hole, a small hemorrhage was noted along a vessel coming off the nerve superotemporally while attempting to engage the posterior cortical vitreous intraoperatively. This patient developed an inferior visual field defect. No intraocular pressure (IOP) measurements greater than 26 mm Hg were recorded in any eye perioperatively. Visual field defects included 4 eyes with inferotemporal defects, 2 eyes with inferior altitudinal defects, 1 eye with a cecocentral scotoma, and 1 eye with a superonasal defect. Only 1 patient had worsened visual acuity. A relative afferent pupillary defect was observed in 4 eyes and disc pallor in 5 eyes. CONCLUSIONS: Central or peripheral visual field loss can now be recognized as a possible complication of vitreous surgery. In some cases, a relative afferent pupillary defect and optic disc pallor are present, suggesting that the optic nerve is the site of injury. Possible mechanisms include ischemia due to elevated IOP or fluctuations in IOP, optic nerve damage from retrobulbar injection, direct intraoperative mechanical trauma to the optic nerve, indirect injury from vigorous suction near the optic nerve leading to shearing of peripapillary axons or vessels, or a combination of these. Certain optic nerves may be more susceptible to injury because of preexisting compromise from glaucoma or vascular disease.

Adult↗

PubMed1978

A pilot study on the use of visual field expanders.

The nature and magnitude of the visual difficulties of five volunteer patients with severely contracted visual field and high visual acuities was investigated by several techniques. These comprised a questionnaire providing a quantitative score of visual impairment, a specially devised visual search task, and an arbitrary method of estimating visual efficiency. Many aspects of visual impairment resulting from contract visual fields were revealed and discussed. Performance scores on the search task indicated that the field expander would probably be useful to a small number of cases for continuous wear, usually as a binocular bioptic system. Other cases might benefit from a clip-on or hand-held device for occasional use. Methods of manufacture and dispensing and difficulty in locating suitable patients were the major limiting factors in this study. The methods of assessment, and the optical system described in this study are worthy of further investigation and development for trial on a larger number of patients.

Eyeglasses↗

PubMed1997

[Visual field examination in limited patient cooperation].

Objective methods to estimate the visual field are necessary, if a conventional subjective perimetry is impossible due to limited cooperation. Objective methods are indicated in infants, handicapped patients, patients with psychogenic visual field loss, and malingerers. An objective estimation of the visual field can be performed by means of pupillary light reflexes, voluntary and involuntary eye movements, and visual evoked potentials. Systematically false responses contain useful information regarding the proof of misrepresentations. The reproducibility of visual field defects can be checked by testing at different distances from the screen. This article reports on handy methods requiring no large-scale equipment.

Adult↗

PubMed1994

Visual field profile of optic neuritis. One-year follow-up in the Optic Neuritis Treatment Trial.

PURPOSE: The purpose of this present study was to evaluate longitudinal visual field information for 448 patients over their first year of follow-up in the Optic Neuritis Treatment Trial. METHODS: We reviewed 6536 automated static visual fields performed on a visual field analyzer (Humphrey Visual Field Analyzer) at nine visits within the 1-year period for each of the patients. RESULTS: The median values of the mean deviations for affected eyes were as follows: -22.88 dB at baseline, -1.94 dB at 6 months, and -1.62 dB at 1 year. At 6 months, 51% of affected eye visual fields were normal, and at 1 year 55.9% were normal. Approximately two thirds (68.8%) of the fellow eyes were classified as abnormal at baseline, although the defects were generally slight. One third (33.2%) were abnormal at 6 months, and approximately one third were still abnormal at 1 year. More than 87% of those abnormal at 6 months and at 1 year had been abnormal at baseline. Binocular analysis revealed that 13.2% of patients showed a chiasmal or retrochiasmal type of field defect at least once during the year (5.1% bitemporal; 8.9% homonymous). Of the patients who showed a retrochiasmal visual field defect, 75.7% had an abnormal magnetic resonance imaging scan at baseline compared with 46% of the rest of the patients in the Optic Neuritis Treatment Trial (chi 2 = 10.73, df = 1, P < .002). CONCLUSION: Over the first year of follow-up, the majority of patients with visual field defects from acute optic neuritis returned to normal, as measured by automated static perimetry. Many fields showed variation in the pattern and location of the sensitivity loss. Chiasmal and retrochiasmal defects occurred more commonly than previously reported.

Acute Disease↗

PubMed1988

Repeated visual field screening in the aged.

During 1977 and 1978 visual screening was performed in 1511 persons born 1907-1921 and taking part in a population survey. 8.4 years later the visual field screening was repeated in 2039 eyes of 1038 persons. The rates of unsuccessful tests improved or remained unchanged. The incidence of non-glaucomatous visual field defects was 0.006/year. Thus repeated visual field screening of persons in their seventies was both feasible and fruitful.

Aged↗

PubMed1994

Red square test for visual field screening. A sensitive and simple bedside test.

A reliable bedside test for screening of visual field defects is a valuable tool in the examination of patients with a putative disease affecting the sensory visual pathways. Conventional methods such as Donders' confrontation method, counting fingers in the visual field periphery, of two-hand confrontation are not sufficiently sensitive to detect minor but nevertheless serious visual field defects. More sensitive methods requiring only simple tools are also described. In this study, a test card with four red squares surrounding a fixation target, a black dot, with a total test area of about 11 x 12.5 degrees at a distance of 30 cm, was designed for testing experience of red colour saturation in four quadrants, red square test. The Goldmann visual field was used as reference. 125 consecutive patients with pituitary adenoma (159 eyes), craniopharyngeoma (9 eyes), meningeoma (21 eyes), vascular hemisphere lesion (40 eyes), hemisphere tumour (10 eyes) and hemisphere abscess (2 eyes) were examined. The Goldmann visual field and red square test were pathological in pituitary adenomas in 35%, in craniopharyngeomas in 44%, in meningeomas in 52% and in hemisphere tumours or abscess in 100% of the eyes. Among these, no false-normal or false-pathological tests were found. However, in vascular hemisphere disease the corresponding figures were Goldmann visual field 90% and red square test 85%. The 5% difference (4 eyes) was due to Goldmann visual field defects strictly peripheral to the central 15 degrees. These defects were easily diagnosed with two-hand confrontation and

Adult↗

PubMed2004

[Applicability of semi-automated kinetic perimetry (SKP) in the assessment of the visual field loss due to retinitis pigmentosa].

PURPOSE: To assess the applicability of a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in patients suffering from the visual field defects due to retinitis pigmentosa. METHODS: Thirty-five patients (19 women, 16 men: mean age 38.4 years) suffering from retinitis pigmentosa (10 with with Usher syndrome, one with Bardet-Biedl syndrome and one with Refsum syndrome) were examined using SKP software, implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). Three stimuli (1114e and 14e obligatory) were used to assess the hill of vision of each patient. The area of each isopter was measured in deg2. The test time was measured automatically in minutes. RESULTS: The visual field results were classified as complete or incomplete midperipheral "ring scotoma" (group I--13 patients) and concentric loss of the visual field (group II--22 patients). The area of 1114e isopter was 6147.5 deg2 in the group I and 1961.7 deg2 in the group II. The area of 14e isopter was 1468.4 deg2 and 781.7 deg2, respectively. The mean test time was 10 min. (range 4-20 min.): 8 min. in the group I and 13 min. in the group II. CONCLUSIONS: There is a large diversity of patterns of the visual field loss in retinitis pigmentosa. SKP, in contrary to widely used manual perimeter, gives a possibility of quantification of the visual field area. Future studies may be able to monitor the progression of the visual field loss caused by retinitis pigmentosa.

Adult↗

PubMed1991

Long-term outcome following trabeculectomy: II Visual field survival.

The long-term changes of the visual field defects of 54 glaucoma patients operated on with trabeculectomy were reviewed. Five years after operation 28% of the patients had suffered from further loss of visual field despite lowering of the intraocular pressure (IOP). All but three of these patients had their postoperative IOP regulated within statistically normal levels (11-21 mmHg). All patients with continued loss of postoperative field were generated from groups of patients with milder to moderate preoperative field defects (stages 0-III classification of Aulhorn, 1979). No patients suffered from sudden field loss after surgery. The mean of the preoperative IOP and the mean of the percent IOP reduction postoperatively were not significantly different in patients with or without continued postoperative visual field loss. This indicates that other factors than normalization of intraocular pressure play an important role in the group of patients with progression of visual field defects following surgery.

Aged↗

PubMed1975

Perception of geometrical arrays tachistoscopically exposed in right and left visual fields.

Geometrical stimuli (48 6-item arrays of familiar forms, e.g., circle), tachistoscopically presented in the right or left visual field, were more accurately perceived in the right than left visual field by 15 college students. Targets about half the length of the displays exposed here were perceived with equal facility in both visual fields (Bryden, 1960). Results suggest that length of array might affect the difference in perceptual accuracy of forms shown in the right and left visual fields. Figures in the right visual field were predominantly processed from left to right, and forms in the left visual field from right to left. Since more symbols were identified in the right than left visual field, the left to right encoding sequence may be more efficient than a right to left movement. Limited experience of most Ss in reading symbols from left to right is probably only one factor. Extensive experience reading alphabetical material from left to right might have developed the physiological mechanism underpinning this sequence more than the one serving the opposite movement.

Adolescent↗

PubMed2000

Multifocal ERG and VEP responses and visual fields: comparing disease-related changes.

Static visual perimetry and the multifocal technique both measure the local effects of diseases of the retina and optic tract. The purpose here is to relate the measures obtained from each technique and to describe this relationship in some diseases. It is important to measure both the implicit time and amplitude of the multifocal ERG (mERG) or multifocal VEP (mVEP) responses. Some diseases affect one measure of the responses but not the other. The comparison of either measure to local sensitivity changes measured with static perimetry (e.g. the Humphrey 24-2 and 30-2) presents a problem. Different stimulus displays are employed. Further, the multifocal responses are displayed with arbitrary spacing between the responses. One approach is to measure the amplitude and implicit time of the multifocal responses and display these values on the same coordinates as in the visual field plots. This allows a qualitative comparison of fields and multifocal responses on the same scale. A second approach involves modifying the Humphrey perimeter software so that the test spots are placed in the centers of the multifocal stimuli (e.g. the center of each hexagon of the mERG display). A third approach involves estimating the thresholds for the regions of the multifocal display by interpolating from values at the standard Humphrey locations. The second and third approaches produce a one-to-one mapping of the multifocal and field measures and allow a quantitative comparison between the two. The relationship between visual fields and multifocal responses, determined through one or more of these approaches, is different depending upon whether the disease primarily affects the outer retina (retinitis pigmentosa), ganglion cell (glaucoma), or optic nerve (ischemic optic neuropathy and optic neuritis).

Electroretinography↗

PubMed2007

Mean deviation fluctuation in eyes with stable Humphrey 24-2 visual fields.

AIM: To describe the expected fluctuation in the mean deviation (MD) scores on a large, long-term series of stable visual field reports for particular grades of defect in order to give clinicians an aid to the correct diagnosis of glaucomatous progression. METHOD: Visual field reports of subjects with five reliable consecutive Humphrey 24-2 visual fields, recorded over a period of at least 3 years, were scored using the Advanced Glaucoma Intervention Study (AGIS) system. The AGIS scores of the first and last visual fields were required to be identical. RESULTS: A total of 202 eyes from 202 patients were used in the study, with a total of 1010 visual fields being used in the analysis. Visual fields with no defect (AGIS score 0) had a 99% confidence interval (CI) of 0.3 dB, mild defects 0.4 dB, moderate defects 0.8 dB, severe 1 dB, and 1.3 dB for end-stage defects when considering variation of MD scores. Using a one-way ANOVA incorporating all stages showed very little fluctuation throughout the series (P=0.96). The correlation between the CI and grade of field defect showed a good positive correlation (r=0.7, P=0.0003) indicating an increase in CI as field defects worsen. CONCLUSION: When considering a series of reliable visual fields in a stable eye, one should expect only very little fluctuation in the MD, indicating that an increase in the MD beyond that of the 99% CI described may suggest progression. The reliability indices of the visual field test should be regarded as a primary consideration when assessing visual fields.

Age Factors↗

PubMed2006

[Is it possible to compensate for visual field defects?].

Is it possible for a driver to compensate for visual field defects by skill along with eye and head movements? Monocular field defects with a normal second eye are no problem, because a normal binocular visual field is adequate for all areas of traffic. A total bitemporal hemianopia creates a special situation, because the patient loses a three-dimensional space behind a vertical line through the point of fixation. He may have no binocular visual field. In this case the ability to participate in certain traffic situations may be limited with reduced risk profile. A real problem is posed by defects in the binocular visual field, e.g., due to lesions of the suprachiasmal visual pathway or due to ocular diseases causing damage to both eyes (e.g., glaucoma, diabetic retinopathy, etc.). Such defects usually cannot be compensated for, neither by skill nor by eye or head movements. Saccadic eye movement training and other procedures are only of limited help. These procedures may provide some compensation for daily use; a complete restoration of the ability to participate in traffic is not possible. Rare exceptions may be patients with damage to the visual pathway acquired peri- or postnatally or in early childhood when there is still enough plasticity in the visual system to develop mechanisms of compensation by completely changing the system of eye and head movements.

Automobile Driving↗