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At least 73 records · Page 4Linked to original sources
PubMed1994

A comparison of automated static dark stimuli with the Humphrey STATPAC program in glaucomatous visual field loss.

Visual field examination is conventionally performed with bright stimuli on a dark background. Dark stimuli on a bright background, however, may provide different information as light increases and decreases are subject to parallel processing in the visual pathway. Twenty five eyes with primary open angle glaucoma and visual field loss were examined with the Humphrey visual field analyser thresholding program 30-2 and the computer assisted moving eye campimeter (CAMEC) using static dark stimuli at four different Weber contrast levels of -10 (n = 9), -22 (n = 25), -37 (n = 14), and -76% (n = 25) on a cathode ray tube with a background luminance of 10 cd/m2. The cumulative results obtained with STATPAC 'pattern deviation' empirical probability maps and the results from each contrast of the dark stimulus at identical test locations were compared at eccentricity annuli bands of 4-9, 10-20, and 21-28 degrees. Dark stimuli of lower contrast provided higher abnormal point detection rates. Furthermore, visual field defects to the low contrast dark stimuli were more extensive than those to the luminous stimuli. In conclusion, dark stimuli allowed the delineation between glaucomatous field defects and the normal regions in the central visual field.

Adult↗
PubMed1994

Dependence of visual stabilization of postural sway on the cortical magnification factor of restricted visual fields.

Monocular visual stabilization of fore-aft and lateral body sway was tested posturographically in normal subjects (wearing visual field blinds) as a function of visual field size and location of the visual field on the central or peripheral retina. Body sway applied to a force- measuring platform is less with central (foveal) vision when central and peripheral visual fields have the same area. If, however, the peripheral field size is corrected by the cortical magnification factor of the retina in the primary cortex, body sway is stabilized by the peripheral retina to the same extent. Thus, there is no functional specialization of central and peripheral retina with respect to balance control. Visual stabilization of upright stance is a function of field size and cortical representation of the retina. The central and the peripheral retina have different thresholds to detect motion; this was surprisingly not reflected in measurements of normal fore-aft and lateral body sway.

Adult↗
PubMed1989

Legal aspects of visual field assessment.

Visual field testing can fail to satisfy the standard of care if the optometrist does not test the patient's visual field when it is necessary, and if, even when testing is performed, it is of insufficient sensitivity. In general, the duty to test the visual field arises when examining symptomatic patients and when a suspicious finding is encountered, but "routine" eye health assessments should include a screening visual field test. In some cases the doctrine of informed consent will require the optometrist to inform the patient that testing of the visual field at threshold should be performed. Documentation of both test results and patient communications should be retained in the record.

Documentation↗
PubMed1990

The use of visual field indices in detecting changes in the visual field in glaucoma.

We present results from 64 glaucoma patients and glaucoma suspects followed up for a median period of 7.4 yr who had a median of seven examinations using Program 31 on the Octopus perimeter. The patients also had manual visual fields recorded on either the Tübinger or Goldmann perimeter during the same period. By examining all manual fields over the follow-up, we classified 37 patients as deteriorating and 27 as nondeteriorating by using predetermined field criteria which we believed to be clinically significant. In a masked fashion, the indices mean defect (MD) and corrected loss variance (CLV), in addition to the three cluster analysis indices SIZ, CLUS, and PCLUS were computed for each patient and regressed on time. When a significant positive index/time slope (P less than 0.05) was defined as indication of deterioration, all indices had remarkably poor sensitivities because their slopes did not reach statistical significance in the great majority of patients. When, regardless of statistical significance, positive slopes were defined as indication of deterioration and negative slopes as nondeterioration, the most sensitive index, PCLUS, still had a sensitivity of less than 65%. The indices were better in detecting the presence or absence of visual field deterioration in fields that were initially normal than in those that were initially abnormal. Since the testing modalities of manual and automated perimetry are different, our study was not designed to compare the sensitivity of one technique over the other. Our study does, however, demonstrate that the indices used currently may not be clinically reliable in the assessment of changes in the visual field.

Analysis of Variance↗
PubMed1994

Normal visual fields measured with Octopus-Program G1. II. Global visual field indices.

To complement results from individual test locations, clinicians also evaluate indices, as they give a succinct overview of the visual field. This, however, requires exact knowledge of their variability. The present study was designed to determine normal interindividual variability of global visual field indices and incorporates a data base of a multicenter study performed with Octopus 201 perimeters using Program G1. The 824 fields thus obtained included 139 fields of 139 healthy volunteers who had undergone two previous visual fields and completed all three phases of program G1. The index mean sensitivity showed a significant and linear decrease with increasing age, 0.064 dB/year of life. The indices loss variance, corrected loss variance, and short-term fluctuation did not correlate significantly with age. Percentiles are given for these visual field indices. While within the limits of normal values provided by the manufacturer for these indices, these results suggest that visual fields with "borderline" values require further clinical investigation in reliable, experienced subjects. The results may help clinicians to better evaluate global visual field indices and, therefore, to detect loss of visual function earlier.

Adult↗
PubMed2000

Epilepsy surgery, visual fields, and driving: a study of the visual field criteria for driving in patients after temporal lobe epilepsy surgery with a comparison of Goldmann and Esterman perimetry.

Twenty four patients who had undergone temporal lobe surgery for epilepsy were assessed to determine (a) whether or not they had developed a visual field defect and (b) if a field defect was present, were the visual field criteria, as required by the DVLA, fulfilled using the monocular Goldmann perimeter test and the automated binocular Esterman method performed on a Humphrey perimeter. A field deficit was found in 13 of 24 (54%) using the Goldmann perimeter and 11 of 24 (46%) by the Esterman method. The second was a more lenient assessment with six of 24 (25%) failing the driving criteria compared with 10 of 24 (42%) by the monocular Goldmann method. Three patients were seizure free but failed the driving criteria. This complication of surgery for temporal lobe epilepsy needs to be discussed with patients before surgery.

Adult↗
PubMedDate not supplied

Representation of the visual field in the striate cortex: comparison of MR findings with visual field deficits in organic mercury poisoning (Minamata disease).

PURPOSE: To compare MR imaging findings of the striate cortex with visual field deficits in patients with Minamata disease and to reestimate the classical Holmes retinotopic map by using the data obtained from comparing visual field abnormalities with degree of visual cortex atrophy. METHODS: MR imaging was performed in eight patients with Minamata disease who had been given a full neuroophthalmic examination, including Goldmann dynamic perimetry. The atrophic portions of the calcarine area were measured in the sagittal plane next to the midsagittal image and represented as a percentage of atrophy of the total length of the calcarine fissure. MR findings were compared with results of a visual field test. RESULTS: The visual field test revealed moderate to severe concentric constriction of the visual fields, with central vision ranging from 7 degrees to 42 degrees (mean, 19 degrees). The ventral portion of the calcarine sulcus was significantly dilated on MR images in all patients. A logarithmic correlation was found between the visual field defect and the extent of dilatation of the calcarine fissure. The central 10 degrees and 30 degrees of vision seemed to fill about 20% and 50% of the total surface area of the calcarine cortex, respectively. CONCLUSION: Visual field deficits in patients with Minamata disease correlated well with MR findings of the striate cortex. Our data were consistent with the classical Holmes retinotopic map.

Atrophy↗
PubMed1993

Nerve fiber layer defects with normal visual fields. Do normal optic disc and normal visual field indicate absence of glaucomatous abnormality?

PURPOSE: When the optic disc has normal appearance with no abnormalities in routine automated perimetry, the subject is not considered to have glaucoma. The purpose of this study is to show how such patients may have localized retinal nerve fiber layer defects with corresponding functional abnormality. METHODS: The authors selected eight eyes of eight patients who had a localized retinal nerve fiber layer defect extending within a few degrees from fovea but in whom the optic disc appearance and Humphrey 30-2 visual fields were normal. Of the eight patients, three had positive family history of glaucoma, two had suspected retinal nerve fiber layer abnormality in routine eye examination, two had increased intraocular pressure (IOP), and one had advanced low-tension glaucoma in one eye with a normal fellow eye. The authors examined the central 10 degrees visual field with 1 degree resolution using Humphrey perimeter and the Ring and Centring programs of the high-pass resolution perimeter. RESULTS: A central field defect corresponding to retinal nerve fiber layer defect was found in six of eight patients: in both 10 degrees Humphrey field and Centring programs (2 eyes), in Humphrey only (2 eyes), and in Centring only (2 eyes). CONCLUSION: The results indicate that retinal nerve fiber layer photographs are helpful in diagnosing glaucoma because early glaucomatous abnormalities cannot be excluded without nerve fiber layer photography. Currently available routine perimetric examination programs do not always detect very early functional damage.

Aged↗
PubMed1978

Normalization of visual fields following bromocriptine treatment in hyperprolactinemic patients with visual field constriction.

Two patients with galactorrhea-amenorrhea and bilateral visual field defects were studied. Routine radiologic examination of each patient revealed a normal sella turcica and no demineralization of the posterior clinoid process. Serum prolactin levels were elevated (patient V. G., 80 ng/ml; patient S. R., 204 ng/ml). Within 2 months of bromocriptine therapy, the serum prolactin levels were normal (patient V. G., 12.21 ng/ml; patient S. R., 8.25 ng/ml) and the bilateral visual field defects were corrected. Bromocriptine has been shown to control prolactin secretion in patients with prolactin-secreting pituitary tumors. Normalization of restricted visual fields following bromocriptine therapy indicates the possibility of an anatomical regression of pituitary hyperplasia or an underlying prolactin-producing microadenoma. It is speculated that the modality of functional galactorrhea reflects hyperplasia of the lactotrophs preceding a nodular and ultimately an adenomatous change. The continuous and prolonged administration of bromocriptine may prevent such a progressive sequence. Further experience is required to validate this possibility.

Adult↗
PubMed2004

A historical review of the representation of the visual field in primary visual cortex with special reference to the neural mechanisms underlying macular sparing.

This article comprises a historical review of the literature pertaining to the representation of the visual field in human primary visual cortex. A brief survey of the anatomy of the visual system is followed by a critical evaluation of the key studies that have informed both the issue of the disproportionate representation of central vision within primary visual cortex, and the anatomical basis underlying the phenomena of macular sparing and macular splitting hemianopia.

Hemianopsia↗
PubMed1978

Optokinetic eye movements in albino rabbits: inversion in anterior visual field.

When visual contrasts are restricted to the anterior sector (90 degrees to 180 degrees) of the albino rabbit's visual field, eye position is dramatically unstable, and when such contrasts are moved, horizontal optokinetic eye movements are inverted: the direction of pursuit is opposite to that of the stimulus. In the posterior visual field stability and optokinetic reactions are normal, as in all parts of the pigmented rabbit's visual field. This phenomenon may be one more of the complex of visual system defects linked to albinism.

Albinism↗
PubMed2006

Topography of the frequency doubling perimetry visual field compared with that of short wavelength and achromatic automated perimetry visual fields.

BACKGROUND: Traquair described the topography of visual field sensitivity as a "hill" or "island" of vision. Achromatic automated perimetry (AAP) demonstrates this shape of the visual field in photopic conditions. Techniques claimed to target the magnocellular pathway (frequency doubling perimetry, FDP) and those using a stimulus targeting the koniocellular pathway (short wavelength (or blue on yellow) automated perimetry, SWAP), might produce one that is different. The authors compared the visual field topography from FDP with those of SWAP and AAP, to investigate whether there were significant differences in their shape. METHOD: A sample of 51 patients with previously confirmed normal perimetry were recruited; either low risk glaucoma suspects or normal controls. AAP, SWAP, and FDP perimetry was performed in random order on the same day. The topography of each field was analysed to determine its average shape and to compare results in the same individuals. RESULTS: The topography of the visual field produced by each perimeter differed significantly. While all three had maximal sensitivity centrally, over the 24 degrees from the centre to the periphery, mean sensitivities decreased by 4.9 decibels (dB) for AAP and 7.3 dB for SWAP, while FDP sensitivities by just 1.8 dB over 20 degrees (the extent of the FDP field). FDP mean sensitivities decreased by approximately 0.3 dB with every 10 year increase in age, compared with 1 dB for AAP and 2 dB for SWAP. CONCLUSION: While the topography of the SWAP (koniocellular) field is steeper than corresponding AAP fields, that of the FDP (magnocellular) visual field was considerably flatter. The difference in this shape may reflect retinotopic or cortical mechanisms, which are specific to the magnocellular pathways.

Adult↗
PubMed2005

Progression of visual field defects and visual loss in trabeculectomized eyes.

PURPOSE: To evaluate progression of visual field (VF) defects and development of visual impairment (low vision and blindness) after trabeculectomy. METHODS: We evaluated retrospectively 138 eyes of 138 consecutive patients over 40 years of age with primary open-angle glaucoma (POAG) or exfoliation glaucoma (EG) operated on by trabeculectomy without antimetabolites. The mean follow-up period was 3.5 years (range 2-5). In 83 eyes, pre- and postoperative VF measured by the same technique were compared to detect progression. Visual acuities (VA) were recorded as Snellen decimal notations. VA of <0.3 to 0.05 was defined as low vision and VA of <0.05 or VF constricted to less than 20 degrees in diameter as blindness. RESULTS: In 34 (41%) of 83 eyes with comparable fields, VF defects progressed because of glaucoma. In logistic regression analysis, severity of preoperative VF loss (P=0.0047) and use of preoperative oral anti-glaucomatous medication (P=0.047) correlated significantly with VF progression. In univariate analysis, also initial intraocular pressure (IOP) reduction after surgery (P=0.023) and IOP reduction from preoperative to last postoperative examination (P=0.036) were significantly smaller in eyes with VF progression. Defect progression did not, however, correlate significantly with the last IOP (P=0.58). Six eyes (4.3%) were blind due to glaucoma preoperatively and 14 eyes (10.1%) at the last follow-up. Visual impairment correlated with the severity of initial VF loss (P=0.008). CONCLUSIONS: Progression of VF defects and development of visual impairment due to glaucoma was fairly common despite trabeculectomy. Both were associated with severity of initial VF defect. In this series, no significant correlation appeared between defect progression and the last IOP, but association between stability of VF and the amount of IOP reduction after surgery indicate that a lower target IOP level particularly in eyes with initially severe VF defect would, however, be needed.

Adult↗
PubMed1981

Average responses evoked by moving grating pattern in the upper, central and lower visual field.

Detectable visual evoked potentials were obtained in man by stimulation in the peripheral visual field with a 0.4 cycle/deg vertical grating pattern of 5 degrees arc subtense which moved twice per second horizontally at 415 degrees/sec through an amplitude of 8 degrees arc. These moving grating stimuli were presented to 10 normal subjects, centered 15 degrees above, or centered around, or centered 15 degrees below a fixation mark. The mean latencies (+/- S.D.) of the positive component of the potential evoked by stimuli to the central and 15 degrees eccentricity lower visual field were 114 +/- 17 msec and 104 +/- 20 msec, respectively, while latencies for 15 degrees eccentricity upper visual field stimuli were significantly (p less than 0.001) later with 148 +/- 20 msec.

Adult↗
PubMed1988

Cartographic deformations in a parabolic visual field map.

Visual fields are traditionally represented in the polar azimuthal equidistant projection. In this map, field areas are increasingly exaggerated with increasing visual angle. To facilitate description of central field defects, enlargement of the central visual field by a parabolic, non-linear projection has been proposed. The cartographic deformations associated with this projection were studied by using mathematical isopter models. A change from equidistant to parabolic projection not only altered relative isopter sizes but also their shapes. Also, the normal nasal-temporal asymmetry was obscured. Thus, the parabolic projection may conceal some types of visual field defects, e.g. loss of the temporal cresent. Neither projection represented surface areas correctly. It is argued that the area-true Lambert's projection would be ideal for visual field representation.

Humans↗
PubMed1990

Oculokinetic perimetry for the assessment of visual fields.

The visual fields of 13 children aged 7 to 16 (mean 10.7 years) were assessed by oculokinetic perimetry (OKP), a technique where the field of vision is tested at reading distance using a simple chart, and the results compared with conventional Goldmann perimetry. Cooperation with testing was greater for OKP than Goldmann perimetry and in some cases OKP was better correlated with clinical findings. The advantages of visual field assessment by OKP for children are the close proximity of observer and child, the absence of the requirement for prolonged fixation, and the inexpensiveness and portability of the testing equipment. The disadvantages are movements of the head, with variability in the distance from the target, and the limitation to the central 25 degrees of the visual field.

Adolescent↗