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PubMed2002

Driving after epilepsy surgery: effects of visual field defects and epilepsy control.

The aim of this study was to assess the eligibility to drive in patients with mesial temporal sclerosis who undergo anterior temporal lobectomy. The two major determinants in a patient's ability to drive after such surgery are visual field defects and their seizure frequency. Thirteen patients were selected. The postoperative seizure frequency was assessed using Engel's criteria. Automated static perimetry was performed which consisted of a Humphrey Field Analyser (HFA) 30-2 Test, one for each eye and a Binocular Esterman 120 Test. Seven out of the 13 (54%) selected patients had no seizures post-operatively (Engel's 1); three (23%) patients had less than two seizures per year (Engel's 2) and three (23%) had more than 90% improvement in the frequency of seizures (Engel's 3). The seven patients with no seizures postoperatively were eligible to apply for a driving licence. Automated static perimetry performed on the same patients revealed three (23%) had normal visual field or non-specific loss, seven (54%) had partial homonymous quadrantanopia, one (8%) had complete homonymous quadrantanopia and two (15%) had bilateral concentric loss attributable to vigabatrin, which may have masked any loss occurring due to surgery. Of the 13 patients, only seven (54%) passed the standardised DVLA Esterman visual field test. Of the six (46%) who failed DVLA Esterman visual field test, one had complete homonymous quadrantanopia, three had incomplete homonymous quadrantanopia and two had concentric loss (due to vigabatrin). Although seven (54%) patients passed the visual field test and seven (54%) patients were seizure free only five of the seven seizure-free patients (i.e. 38% of the total number of patients) had visual fields that would make them eligible to drive. As driving is now stated by patients' as a major factor that improves their quality of life, it is important to stress the significance of surgically induced or other iatrogenic visual field defects that may prevent them from driving prior to the operation to avoid disappointments afterwards.

Adult↗

PubMed2005

Characteristics of visual field defects by scanning laser ophthalmoscope microperimetry after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: To evaluate visual field defects after radial optic neurotomy (RON) for the treatment of central retinal vein occlusion (CRVO) by using scanning laser ophthalmoscope microperimetry. METHODS: Thirteen eyes of 13 patients with severe vision loss (< or = 20/200) from CRVO who underwent pars plana vitrectomy and RON had postoperative Goldmann kinetic perimetry, scanning laser ophthalmoscope microperimetry, and fluorescein angiographic evaluation. RESULTS: After a mean follow-up of 8 months, 6 of the 13 patients had visual improvement by > or = 2 lines. Eight patients developed an anastomosis at the radial cut. Postoperatively, sectorial visual field loss arising from the optic head was found by Goldmann perimetry in six patients, and a thin nerve fiber bundle defect was found in three patients. Four patients had no detectable visual field defect shown by Goldmann perimetry, but microperimetry demonstrated an absolute nerve fiber bundle defect arising from the radial cut at the optic disk for three of these patients. CONCLUSION: Visual field loss after RON for the treatment of CRVO is a frequent complication. The etiology of this visual loss appears to be a combination of mechanical trauma to the nerve fiber layers and ischemia of the optic disk circulation.

Adult↗

PubMed1999

The favorable effect of topical betaxolol and timolol on glaucomatous visual fields: a 2-year follow-up study.

BACKGROUND: It has been suggested that beta-adrenergic antagonists might have mechanisms of action other than ocular hypotensive effects affecting the visual function in glaucoma patients and that betaxolol might protect the visual field better than others. A randomized, double-blind study was conducted to compare the effects of betaxolol and timolol on visual fields of glaucoma patients. METHODS: Sixty-four glaucoma patients were treated with either 0.5% betaxolol or 0.25% timolol eyedrops twice daily. The Octopus visual field performance was followed up for 2 years and analyzed to find diffuse and localized changes. We analyzed the change in the mean sensitivity (MS) and performed a cluster analysis and clinical assessment of the visual fields in both treatment groups. RESULTS: The mean sensitivity (MS) improved significantly and equally in both treatment groups. There was a tendency towards more improved clusters in the betaxolol group than in the timolol group and more worsened cluster in the timolol group than in the betaxolol group, but the difference was not statistically significant. The clinical assessment also showed no statistically significant difference between the two groups. CONCLUSION: In the present study both betaxolol and timolol had a favorable effect on the visual fields of glaucoma patients. There was no statistically significant difference between betaxolol- and timolol-treated patients either in the change in mean retinal sensitivity or in the change in localized scotomatous areas.

Administration, Topical↗

PubMed1995

Image processing of computerised visual field data.

BACKGROUND: Computerised perimetry is of fundamental importance in assessing visual function. However, visual fields are subject to patient response variability which limits the detection of true visual loss. METHODS: A method of improving the repeatability of visual field data was demonstrated by applying techniques used in image processing. An illustrative sample of nine normals and nine patients with field loss was used. Two successive Humphrey fields were selected for each subject. Repeatability was defined as the standard deviation of the pointwise differences between sensitivity values of the reference field and repeat field. The field data were then separately subjected to Gaussian and median image processing filters and the repeatability was compared with the unprocessed field results. RESULTS: Improvement in repeatability, by a factor of approximately 2, was demonstrated by both processes. CONCLUSION: These techniques may improve the reliable detection of loss of visual function using computerised perimetry.

Adult↗

PubMed1991

[A case of whole visual field visuomotor ataxia of bilateral hands associated with bilateral parietooccipital lesions in the white matter].

A 29-year-old male with visuomotor ataxia was reported. Visuomotor ataxia of bilateral upper extremities was noted in whole visual field including central visual field (optische Ataxie). Neither contraction nor depression of visual field was detected by the test using kinetic or static perimeter, respectively. Magnetic resonance imaging and computed tomography of the brain revealed bilateral parietooccipital lesions in the white matter, and pathological examination of brain biopsy specimen demonstrated demyelination. We considered that bilateral parietooccipital lesions in the white matter were responsible for visuomotor ataxia in this case.

Adult↗

PubMed2005

Early detection of glaucomatous visual field loss: why, what, where, and how.

This article provides a basis for understanding modern visual field analysis techniques. It describes some of these tests, including their advantages and disadvantages, and the settings in which different tests might be used most successfully. It also includes an examination of the value of visual field assessment from a public health standpoint with particular attention paid to morbidity, cost/benefit ratios, and quality of life correlations.

Glaucoma↗

PubMed1984

[Visual field differences in a letter classification task in unilateral and bilateral presentation conditions].

Kimura's "access model" (1966) of functional difference between the two cerebral hemispheres was examined in a letter classification task. Subjects were required to judge whether or not two Japanese Kana letters in different forms, simultaneously or successively presented, had the same phonemes. Letter stimuli were tachistoscopically projected unilaterally in either right visual field (UR) or left visual field (UL), or bilaterally one in each visual field (B). In successive condition, three interstimulus-interval (ISI) conditions were provided, and bilateral pairs were divided into BL and BR conditions according to the visual field of the first letter. RTs for UR were shorter than UL both in simultaneous and successive conditions. Bilateral pairs in simultaneous condition showed shorter RTs than UL. In successive condition, both BL and BR showed longer RTs than UR in all ISI conditions. The fact that RTs for BL did not approach to UR suggested the necessity of some additional assumptions to Kimura's access model. Reservation of the processing of first stimuli was discussed as one of the possible interpretations for the present results.

Dominance, Cerebral↗

PubMed2004

Relationship between the extent of peripheral anterior synechiae and the severity of visual field defects in primary angle-closure glaucoma.

We investigated the relationship between the circumferential extent of peripheral anterior synechiae (PAS) and the severity of visual field defects in primary angle-closure glaucoma (PACG). Correlations between visual field defects and the extent of PAS were analyzed in 73 eyes; 28 with and 45 without acute attacks. Spearman's correlation coefficient between the severity of visual field defects and the extent of PAS was 0.348 (P = 0.003) in all subjects (n = 73), 0.377 (P = 0.012) in the PACG eyes without acute attacks (n = 45), and 0.338 (P = 0.079) in the eyes with acute attacks (n = 28). Our results showed a statistically significant correlation between the extent of PAS and the severity of visual field damage in PACG overall, and especially in PACG patients without a history of acute attacks.

Aged↗

PubMed1982

Ipsilateral visual field represented in the cat's visual cortex.

Responses to visual stimulation were recorded in cells from the border region between cortical areas 17 and 18 in anaesthetized cats. There was found to be a band of ipsilateral representation, the cells of which had rather large receptive fields centered up to 8-12 degrees into the ipsilateral hemifield. The edges of the receptive fields extended 2-3 degrees still further ipsilaterally. The cortical region involved is very small, however, stretching 0.2-1.0 mm mediolaterally, and possibly restricted largely to layers II and III. Hence, in cats, as in sheep and hamsters, there is a band about 20 degrees wide of visual field along the naso-temporal division that is represented in the visual cortices of both hemispheres.

Animals↗

PubMed1988

Confidence intervals for change in automated visual fields.

Three successive fields of 136 eyes (86 patients) were extracted from our data base containing over 3000 visual fields performed on the Humphrey visual field analyser with program 30-2. Series of fields in which the second field was depressed relative to the first were selected for analysis to determine how much change between the first two fields was required to predict a downward trend as confirmed by the third field in the series. The data were stratified with respect to initial field damage. Seven regions of the visual field were analysed including the upper and lower temporal and nasal quadrants, the superior and inferior Bjerrum regions, and the whole field. Minimally damaged regions required between 4.7 and 5.6 dB change in mean sensitivity, whereas more damaged regions required between 5.5 and 7.2 dB change in mean sensitivity to have 95% confidence that the negative trend would be confirmed by the third field. The superior Bjerrum region was the most sensitive for the detection of change, and the lower temporal region was the least sensitive. We conclude from this series of data that large changes between two successive fields are required to be sure that the changes are due to disease rather than chance fluctuation. Where any doubt exists, the field should be repeated to confirm the reality of change.

Aged↗

PubMed2004

Effects of moderate smoking on the central visual field.

PURPOSE: To investigate whether moderate cigarette smoking has any effects on the central visual field. METHODS: This study included 30 healthy, moderate cigarette smokers (10-20 cigarettes per day for at least the past 5 years) and 22 healthy non-smokers. After two training test sessions, all individuals underwent computerized visual field examinations (Humphrey 30-2 Full Threshold Test) with both white-on-white (W-W) perimetry and blue-on-yellow (B-Y) perimetry. One eye of each subject with reliable visual field test results was evaluated. The foveal threshold, mean deviation (MD), pattern standard deviation (PSD), short-term fluctuation (SF), corrected pattern standard deviation (CPSD), glaucoma hemifield test (GHT) and number of significantly depressed points deviating at p < 5%, p < 2%, p < 1% and p < 0.5% on the pattern deviation probability map of the smokers were compared with those of the non-smokers. RESULTS: When the results of W-W perimetry were analysed, the smokers were found to have significantly lower foveal thresholds (p = 0.001) and mean retinal sensitivity (p = 0.02), and higher PSD (p = 0.002) and CPSD (p = 0.01) than the non-smokers. Short-term fluctuation was similar in both groups (p = 0.55). The number of significantly depressed points deviating at p < 5%, p < 2% and p < 1% on the pattern deviation probability map was similar for both groups (p > 0.05). The number of depressed points deviating at p < 0.5% on the pattern deviation probability map was higher for the smokers than for the non-smokers (p = 0.03). The results of B-Y perimetry showed the smokers to have a significantly lower foveal threshold than the non-smokers (p = 0.03). However, there were no significant differences in the global indices of the two groups (p > 0.05). The number of significantly depressed points deviating at p < 5%, p < 2%, p < 1% and p < 0.5% on the pattern deviation probability map was similar in both groups (p > 0.05). No significant difference in GHT was determined with either perimetry for the smokers compared with the non-smokers (p > 0.05). CONCLUSION: This study suggests that moderate cigarette smoking is associated with both diffuse and localized reductions in retinal sensitivity with W-W perimetry. Only reduction in the foveal threshold was observed with B-Y perimetry, with no hints of diffuse and localized reductions.

Adult↗

PubMed1990

Do visual field deficits exacerbate visuo-spatial neglect?

A significant association between visual field deficits (VFD) and visuo-spatial neglect is well established, although cases of double-dissociation between the two conditions are not uncommon. It has been argued that VFD typically exacerbates the behavioural manifestations of neglect. We examined a series of 51 patients with unilateral right-hemisphere stroke for the presence of visual field deficit and visuo-spatial neglect. Patients were assigned to the neglect group (N+) or the non-neglect group (N-) on the basis of their aggregate scores on the recently standardised Behavioural Inattention Test (BIT). The association between neglect and VFD was confirmed. Four groups of eight patients (N+, VFD+; N+, VFD-; N-, VFD+; N-, VFD-) were then selected from the initial sample so that they were matched for age, IQ, and days post onset of stroke. Within the neglect groups, the severity of neglect did not differ significantly between those patients with and without VFD; within the non-neglect groups, scores on subtests of the BIT likewise did not differ (with the sole exception of Letter Cancellation) between the VFD+ and the VFD- subgroups. It was concluded that visual field deficits do not exacerbate neglect, and that poor functional recovery in many patients with VFDs is due to the association of sensory loss with the underlying causal factor of neglect.

Aged↗

PubMed1980

Computerized visual field screening in the management of patients with ocular hypertension.

Visual field testing which the Computer fully automatic computerized perimeter (Heijl & Krakau 1975) employing a supra-liminal screening test procedure was used in a material of 1013 eyes with ocular hypertension in which earlier routine perimetry (kinetic and static) on the Goldmann perimeter had yielded a normal result. The automatic screening was repeated if positive, and manual control perimetry was used in order to confirm or reject identified field defects. This procedure revealed field defects that could be confirmed at both automatic and manual perimetry in 3.6% of the eyes. In the control group the incidence of field defects found at manual perimetry during the same time interval was calculated at 0.4%. Thus automatic screening revealed several times more field defects than manual routine perimetry. Eyes in which repeated automatic screening had indicated defects which manual control perimetry failed to confirm, showed a high percentage of field loss at later follow-up. The results are discussed, and the conclusion is drawn that automatic screening is clearly superior to manual routine perimetry used at present. The most practical solution in many eye departments would be to use a computerized perimeter for the visual field screening of glaucoma suspects.

Adult↗

PubMedDate not supplied

Effects of betaxolol and latanoprost on ocular blood flow and visual fields in patients with primary open-angle glaucoma.

PURPOSE: To evaluate the effects of betaxolol and latanoprost on ocular blood flow and visual fields in patients with primary open-angle glaucoma (POAG) by means of an observer-masked, prospective clinical study. METHODS: Thirty-two patients with newly diagnosed POAG were included in the study. The patients were randomized into two groups. The first group was treated with betaxolol 0.50% twice daily and the second group with latanoprost 0.005% once daily. Baseline and posttreatment examinations on the first and third months of treatment included intraocular pressure (IOP) measurement, automated visual field testing, and ocular blood flow assessment. For evaluation of visual fields, mean defect and pattern standard deviation indices were used. Ocular blood flow was assessed by means of color Doppler imaging of the central retinal artery (CRA) and the temporal short posterior ciliary artery (PCA). For each vessel, peak systolic (PSV) and end-diastolic (EDV) blood flow velocities were measured and resistivity index (RI) calculated. RESULTS: After exclusion of one noncompliant patient, the study was completed with 31 eyes of 31 patients. Both drugs significantly reduced IOP (p<0.05). The mean IOP lowering effect of latanoprost was significantly higher than that of betaxolol (p=0.03). Visual field indices exhibited no significant changes in either group (p>0.05). There were no significant changes in PSV or EDV measurements of CRA or PCA in either group (p>0.05). RI decreased in both CRA and PCA with both drugs. The mean changes between baseline and 3 month blood flow measurements were not significantly different between betaxolol and latanoprost (p>0.05). CONCLUSIONS: Over a treatment period of 3 months, both betaxolol and latanoprost tended to improve ocular blood flow without one of them being superior to the other. The results suggest that the direct (non IOP-dependent) influence on ocular circulation is better for betaxolol than for latanoprost. In addition, neither drug caused significant generalized improvements in visual fields during this period.

Antihypertensive Agents↗

PubMed1986

The normal visual field on the Humphrey field analyzer.

To provide a bank of normal perimetric data, we tested the central and peripheral visual fields of 102 novice normal subjects using the Humphrey automated perimeter. All eyes used for visual field testing were first carefully examined to be sure that they were, indeed, normal. We calculated population means and standard deviations of each test location and for each decade for age. Average differential light sensitivity decreased with advancing age: -0.5 dB/decade at fixation, -0.6 dB/decade in the central (30-2) field, and -06. dB/decade in the peripheral (30/60-2) field. However, neither the slope nor the shape of the hill of vision changed with aging. Short-term fluctuation was not constant throughout the visual field, but instead was greater in the periphery than the center.

Adult↗

PubMed1981

Representation of the visual field in the optic tract and optic chiasma of the cat.

The fibre arrangement in the optic chiasma (OC) and tract (OT) was investigated with anatomical and physiological methods. In silver impregnated material, principal fibre streams can be demonstrated. In the OC, fibre bundles from each eye cross in a regular basket weave pattern, but deviations of single fibres from the predominant stream are often seen. In the OT, fibres run essentially parallel, and crossings of individual fibres are mainly restricted to the periphery of the tract, or around capillaries. Fibres in the upper segment of the OT are of thin, in the lower segments of thick diameter. Individual fibres labelled by HRP injected in the lateral geniculate body (LGB) run essentially parallel over long distances. Ventromedially to the LGB, bifurcations are found with one branch entering the LGB, the other continuing. 57% of OT-fibres had a receptive field (RF) in the contralateral, 43% in the homolateral eye; 60% in the lower, 40% in the upper visual field; and 6% had a RF in the homolateral visual field, mostly near the vertical meridian. Fibres from the central area were underrepresented in our sample. Fibres from the two eyes were mixed. The RFs of consecutively recorded fibres showed a systematic progression only exceptionally. After plotting RFs of a single penetration on a transformed isodensity ganglion cell map of the visual field, the RF's were distributed along elongated paths on this map. In the OT, such paths ran parallel or slightly inclined relative to the horizontal meridian. They were restricted to either the upper or the lower quadrant or to a path along the horizontal meridian. In the OC, the RF-paths mostly crossed the horizontal meridian at an obtuse angle (average 70 degrees). Thus, the visual field representation rotates by nearly 90 degrees from the OC to the OT. In the OC, the central area is located anteriorly, in the OT dorsally, with the upper visual quadrant laterally and the lower medially. Fibres from the two eyes were mixed and, within the range of the scatter, RFs from the homo- and contralateral eye were in register. It is concluded, that the distribution of fibres in the OC and the OT show a basic retinotopic organization superimposed by scatter.

Animals↗

PubMed2002

Projected impact of travoprost versus both timolol and latanoprost on visual field deficit progression and costs among black glaucoma subjects.

PURPOSE: We compared differences associated with use of travoprost and latanoprost on both progression of perimetric loss over time and associated costs among black patients. METHODS: Patients with primary open-angle glaucome or ocular hypertension were randomly assigned to one of four arms in a 12-month, double-masked study: travoprost (0.004% or 0.0015%), latanoprost (0.005%), or timolol (0.5%). Forty-nine patients received 0.004% travoprost, 43 received latanoprost, and 40 received timolol. We applied algorithms found in published studies that link intraocular pressure (IOP) control to visual field progression and calculated the likelihood of visual field deterioration based on IOP data. This was used to estimate differences in medical care costs. RESULTS: The average IOP was lower for patients receiving travoprost than for patients receiving latanoprost or timolol (17.3 versus 18.7 versus 20.5 mm Hg respectively, P < .05). Travoprost-treated patients had a smaller predicted change in visual field defect score (VFDS) than latanoprost-treated patients and timolol-treated patients, and significantly fewer were expected to demonstrate visual field progression. Medical care costs would be higher for latanoprost-treated and timolol-treated patients. CONCLUSIONS: Recent studies have provided algorithms linking IOP control to changes in visual fields. We found that treatment with travoprost was associated with less visual field progression and potential cost savings.

Aged↗

PubMed1995

Comparing threshold visual fields between the Dicon TKS 4000 automated perimeter and the Humphrey Field Analyzer.

BACKGROUND: The automated perimeter is becoming the instrument of choice in the analysis of the visual field. There are a number of different perimeters in use and it can be difficult to compare results from different instruments. The purpose of this study was to compare visual field threshold measurements determined by the Humphrey Field Analyzer and the Dicon TKS 4000. METHODS: This study provided a statistical comparison of field test results from the Dicon TKS 4000 Automated Perimeter (program number 9) and the Humphrey Field Analyzer (30-2 threshold using FastPac). Central 30 degree, 76 point full threshold fields were performed on 20 non-dilated optometry students (age range 21 to 32 years, mean age 25.1 years) using both instruments. For the purpose of statistical analysis, the visual field was divided into 24 sectors, each measuring 10 degrees by 10 degrees. The mean threshold value of each group of points was compared between instruments. RESULTS: A difference was found between instruments (significant at P&0.0001) for 19 of 24 sectors. In addition, the Humphrey Field Analyzer threshold values were consistently higher (average difference 2.47 dB) than the Dicon values. Each subject was tested twice on each instrument; both instruments showed high test-retest correlations: 0.970 for the Humphrey and 0.971 for the Dicon. Test administration times were comparable (average 435.2 seconds for the Humphrey Field Analyzer and 430.2 seconds for the Dicon), although the Dicon averaged 41.5 fewer presentations tested per examination. Fixation losses were higher with the Dicon instrument. CONCLUSIONS: A practitioner may be reluctant to directly compare test results between the two instruments since they produce threshold values of statistically significant differences. The Dicon TKS 4000 was subjectively preferred over the Humphrey Field Analyzer by most subjects.

Adult↗