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PubMed1992

A visual field quantification system for the Goldmann Perimeter.

We have developed a visual field quantification system that can accurately quantify the measurement results by the Goldmann Perimeter (GP). This system calculates the plural indexes introduced in published papers. In recent years, several isopter quantification methods have been proposed. In these methods, the isopters are digitized and the data are input into a computer, after which a computer program evaluates the changes in the isopters quantitatively. However, each program is only able to evaluate private indexes. We have developed a system that quantifies data using multiple methods. This system used five methods that have been introduced in published papers. With this system, a physician can analyze GP data with multiple methods and can diagnose diseases accurately. We have already input about 2500 GP recording papers into the computer by this system. We then calculated the plural indexes, and visualized the temporal changes in the perimetry.

Humans↗
PubMed1985

Semantic priming effects for stimuli presented to the right and left visual fields.

Studies that have addressed the possibility of hemispheric differences in semantic priming effects have yielded contradictory results. This paper reports the findings of two experiments intended to shed greater light on the issue of hemispheric differences in semantic priming. Experiment 1 used a hemiretinal paradigm and examined manual response latency and response accuracy to four types of word pairs; categorically related, syntactically related, unrelated, and pairs containing a nonword member. Experiment 2 examined the effects of unrecognized, disambiguating flank words on verbal responses to a centrally presented homograph. Experiment 1 yielded no significant visual field differences in magnitude of priming effects when response latency served as the dependent measure, although categorical relatedness facilitated response accuracy for left but not right visual field stimuli. In experiment 2, the disambiguating words had a significant effect on meaning interpretation of the homographs that was independent of visual field of presentation. Taken together, the results of these studies are interpreted as indicating that semantic aspects of linguistic input are automatically processed and can influence the content and latency of subsequent responses, whether presented to the left or right visual field.

Adolescent↗
PubMedDate not supplied

Overrepresentation of the central visual field in the superior colliculus of the pigmented and albino ferret.

We have examined the retinotopy in the superior colliculus of pigmented and albino ferrets using both anatomical and electrophysiological methods. While the distribution of contralaterally projecting retinotectal ganglion cells is characterized by the presence of an area centralis superimposed on a visual streak in both strains, the ipsilateral projection from temporal hemiretina is strongly reduced in albinos. In spite of the significantly altered retinotectal projection pattern, the collicular visual field map in the albino ferret reveals the same characteristics as in the pigmented animal with a strongly enlarged representation of the center of visual space. An areal comparison between retinotectal ganglion cell distribution and collicular areal magnification shows that the increase in areal magnification factor between the periphery and the representation of the central visual hemifield exceeds the corresponding increase in retinal ganglion cell density between peripheral retina and area centralis by a factor of three in pigmented and a factor of four in albino ferrets. The areal magnification factor of the representation of the retinal visual streak does not exceed the increase in retinotectal ganglion cell density. Thus, our results suggest that the representation of visual space in the superior colliculus of albino and pigmented ferrets does not simply follow the retinotectal ganglion cell density, but that there is an enhanced representation of the frontal central visual field. The possibility is discussed that the collicular visual field map may be determined either by both retinotectal and corticotectal projections or by the colliculus' intrinsic structure.

Albinism, Ocular↗
PubMed2005

Menstrual cycle-dependent changes in white-on-white visual field analysis of diabetic women.

AIM: To determine the effect of the menstrual cycle on white-on-white perimetry (WWP) tests of diabetic women. SUBJECTS AND METHODS: Left eyes of 129 normally menstruating women (81 type 1 diabetes mellitus (DM) with mild (n = 43) and severe (n = 38) non-proliferative diabetic retinopathy (NPDR), and 48 healthy control females) were included in the study. All subjects underwent complete ocular examination and WWP tests both in the follicular (7-10th day of the cycle) and luteal phases (days 3-7 before the bleeding) of two consecutive menstrual cycles. WWP was performed using Humphrey Field Analyzer II with SITA Standard, central 30-2 program. Mean sensitivity (MS) of points located at central 3, 9, 15, 21 and 27 degrees retinal locations (4, 12, 18, 24 and 16 points, respectively) were calculated in all menstrual phases. RESULTS: The mean age of diabetic patients with mild and severe NPDR and control subjects were 28.8 +/- 4.7, 30.1 +/- 5.9 and 29.4 +/- 5.1 years, respectively (p > 0.05). Their mean MS values were 30.7 +/- 1.0, 30.4 +/- 1.0 and 30.8 +/- 0.8 dB, respectively (p > 0.05). Diabetic patients with severe NPDR demonstrated significant decreases in mean MS values of peripheral 21 and 27 degrees visual field locations in the luteal phase (p < 0.05). However, changes in that of the locations within central 15 degrees visual field were non-significant (p > 0.05). Diabetic patients with mild NPDR and control subjects demonstrated no significant changes in mean MS values of any of the visual field locations (p > 0.05). CONCLUSION: Peripheral, rather than central, locations of central visual field of diabetic women with severe NPDR demonstrated a significant retinal sensitivity loss in the luteal phase. These findings should be taken into consideration during the clinical follow-up of diabetic women at risk of glaucoma and ocular hypertension.

Adult↗
PubMed1997

The role of visual field position in pattern-discrimination learning.

Invariance of object recognition to translation in the visual field is a fundamental property of human pattern vision. In three experiments we investigated this capability by training subjects to distinguish between random checkerboard stimuli. We show that the improvement of discrimination performance does not transfer across the visual field if learning is restricted to a particular location in the retinal image. Accuracy after retinal translation shows no sign of decay over time and remains at the same level it had at the beginning of the training. It is suggested that in two-dimensional translation invariance-as in three-dimensional rotation invariance-the human visual system is relying on memory-intensive rather than computation-intensive processes. Multiple position- and stimulus-specific learning events may be required before recognition is independent of retinal location.

Adult↗
PubMed1989

The visual field in advanced glaucoma.

For analysis of the morphology of the visual field in advanced glaucoma, we tested 62 eyes of 54 late stage glaucoma patients using program 10-2 on the Humphrey Field Analyzer. The fields, which were already reduced to a small central isle, had mostly typical, asymmetric borders with their largest extend to the temporal lower quadrant and their smallest extend to the upper nasal quadrant. An upper nasal step was very frequent. The boundaries are equivalent to the retinal nerve fiber lines. Actually, the glaucomatous isle is a 'centro-coecal isle', representing a remnant of intact maculo-papillary nerve fiber bundles. A test with a 2 degrees spacing like the Humphrey program 10-2 proved to be useful for routine perimetry in these cases.

Adolescent↗
PubMed1988

Adaptation to movement in right and left visual fields.

102 subjects reported on movement aftereffects (MAEs) produced by stimuli presented in the left or right visual field. MAEs were both faster and longer when the stimuli were presented in the right visual field. Possible reasons for the asymmetry are discussed.

Adaptation, Physiological↗
PubMedDate not supplied

Association between nocturnal blood pressure reduction and progression of visual field defect in patients with primary open-angle glaucoma or normal-tension glaucoma.

PURPOSE: To assess prospectively the relationship between nocturnal blood pressure reduction (dip) and progression of the visual field defect in patients with normal-tension glaucoma (NTG) or primary open-angle glaucoma (POAG). PATIENTS AND METHODS: The subjects studied were 38 patients with glaucoma (23 patients with NTG, 15 patients with POAG), in whom 48-h ambulatory blood pressure monitoring was conducted, who were followed for at least 4 years, and in whom reliable visual field tests were performed at least 5 times. The progression was determined by the mean deviation (MD) slope analysis system installed in the Humphrey field analyzer Statpac program. Glaucoma patients with a dip of <10% were assigned to the nondipper group, those with a dip of 10%-20% to the tipper group, and those with a dip of >20% to the extreme dipper group. The dipper group was defined as physiologic dippers, while the nondipper and the extreme dipper groups were defined as nonphysiologic dippers, to study the relationship between the disturbance of the dip and progression of the visual field defect. RESULTS: Thirteen patients showed significant progression, while 25 patients did not. There were no significant differences in the mean intraocular pressure and follow-up period between the patients with progression and those without progression. Half (7/14) of the nondippers, 20% (4/20) of the dippers, and 50% (2/4) of the extreme dippers showed progression, indicating a tendency of progression in the nondipper and the extreme dipper groups. The nonphysiologic dippers had a higher incidence of progression compared with the physiologic dippers (P = 0.05). Among the glaucoma patients in the nondipper and dipper categories only, those with progression had significantly smaller dips (P = 0.02). CONCLUSION: These results suggest that disturbance in the physiologic dip may be involved in the progression of glaucoma.

Blood Pressure↗
PubMed2002

The severity and spatial distribution of visual field defects in primary glaucoma: a comparison of primary open-angle glaucoma and primary angle-closure glaucoma.

OBJECTIVE: To compare the characteristics of visual field defects in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG). METHODS: Subjects with primary glaucoma aged 30 years and older were prospectively considered for inclusion. Automated static white-on-white perimetry was performed. A minimum of 2 reliable tests was required with a mean deviation (MD) within 2 dB on 2 tests. Subjects with previous symptomatic angle-closure, normal-tension glaucoma, visually significant cataract, or previous intraocular surgery were excluded. RESULTS: Of 234 subjects assessed, 129 had POAG, and 105 had PACG. The MDs (POAG group, -13.3 dB; PACG group, -18.0 dB) indicated more severe visual loss in subjects with PACG. In subjects with POAG, the superior hemifield was more severely affected than the inferior. This was less pronounced in subjects with PACG. Following stratification by MD, the difference between hemifields was marked in the mild (-10 dB<or=MD) and moderate (-20 dB<or=MD<-10 dB) subgroups but was not present in the severe (MD<-20 dB) subgroup. We detected differences between POAG and PACG in retinal sensitivity between the superior and inferior hemifields, independent of severity of damage. CONCLUSIONS: The pattern of visual field loss was different in the 2 diseases. This may give insight into the pattern of visual loss in predominantly pressure-dependent glaucomatous optic neuropathy.

Aged↗
PubMed1984

The representation of the visual field in parvicellular and magnocellular layers of the lateral geniculate nucleus in the macaque monkey.

Two-dimensional maps of individual layers of the dorsal lateral geniculate nucleus (LGN) in the macaque monkey were constructed and used as a basis for comparing laminar size, shape, and topographic organization. Topographical data from the electrophysiological investigation of the LGN by Malpeli and Baker ('75) were displayed on maps of all six layers. As known from previous studies, there is a significant over-representation of central vision in the LGN. Unexpectedly, though, the visual representation is anisotropic over portions of most LGN layers. That is, the linear magnification factor (millimeters along the laminar surface per degree of visual field) is not equal for all directions from a given point in the visual field. Moreover, the visual representations in the parvicellular and magnocellular divisions of the LGN differ both in their emphasis on central vision and in their anisotropies. To determine the degree of individual variability, laminar maps were prepared from the LGN of seven other hemispheres. The shapes of laminar maps varied considerably between LGNs, from nearly circular to highly elliptical, but the surface area was relatively constant for each layer. Topographical organization, determined by mapping the optic disc representation on the LGN laminae and by labeling from anterograde and retrograde tracer injections in striate cortex, showed significant individual variability. Interestingly, the visual representations in the LGN and striate cortex are topologically inverted with respect to one another. This indicates that the establishment of geniculocortical connections involves a systematic crossing-over of fibers. Information on cell densities and magnification factors in striate cortex obtained from other studies was compared to the results of the present study in order to estimate ratios of cortical neurons to LGN neurons at different eccentricities. The total number of cortical neurons per LGN neuron is about 130 on average, but it extends over approximately a tenfold range, from less than 100 in the far periphery to nearly 1,000 in the fovea. The estimated number of cells in layers 4A and 4C beta per parvicellular layer neuron is smaller and extends over a slightly narrower range, from 30 to 240, whereas the number of layer 4C alpha neurons per magnocellular neuron varies more widely, from about 45 to 7,000.

Animals↗
PubMed1982

Left visual field superiority in a letter-naming task for both left- and right-handers.

Subjects identified on the basis of sex, handedness, and handwriting posture performed a letter-naming task. Single letters were shown briefly in the left or right visual field and the subject was required to name the letter as quickly as possible. Both left- and right-handers had shorter response latencies when the stimulus was presented in the left visual field. Response latency decreased across trials, however, the decrement was largest to right visual field stimuli. In addition, males produced significantly faster reaction than did females.

Discrimination Learning↗
PubMed1980

[Reproducibility of central visual field testing using kinetic or computerized static perimetry (author's transl)].

Under controlled conditions the differences between duplicated examinations with the Goldmann kinetic perimeter and the Krakau/Heijl static computerized perimeter were evaluated. Kinetic visual fields were obtained independently by two well trained examiners and duplicate examinations were performed by computer perimetry. The differences between the two examinations were statistically evaluated using quantitative criteria. The agreement between first and second examination--based on normal and pathologic findings--was 72% for the Goldmann and 88% for the computer perimeter. The greater reproducibility of central visual field testing with the computer perimeter is most probably due to the subjectivity of the observer in the kinetic manual technique. The computer obviously represents a standardized observer using a constant strategy with a fixed time course. The computerized perimeter was easy to operate and did not require a specially trained technician. All the patients in whom kinetic visual field testing was possible were able to undergo computerized perimetry.

Adolescent↗
PubMed1993

Responses to facial and non-facial stimuli presented tachistoscopically in either or both visual fields by patients with the Capgras delusion and paranoid schizophrenics.

An experiment was carried out designed primarily to test A B Joseph's suggestion that patients with Capgras delusion may have problems integrating information between the two cortical hemispheres; and at the same time it was meant to examine J Cutting's ideas linking schizophrenia in general, and the Capgras delusion in particular, to right hemisphere dysfunction. Three patients with the Capgras delusion and three matched controls diagnosed as paranoid schizophrenics were briefly presented pairs of line-drawn object and photographs of faces randomly in the left visual field, the right visual field or bilaterally. The results with objects revealed no particular pattern of performance for either group; but, when faces were shown, the controls revealed the usual left visual field/right hemisphere advantage while for the Capgras group this was reversed. The results are not consistent with a simple prediction from Joseph's hypothesis but they are in accord with Cutting's theory-though they also pose some problems for it, which are discussed.

Adult↗
PubMed1983

Name and face matching in one or two visual fields: a test of models of hemispheric specialization.

In two experiments a name and a face (each male or female) were simultaneously flashed to either the same or opposite visual fields (left or right), for matching congruent (same sex) or incongruent (opposite sex), to test the predictions of various models of hemispheric specialization. While overall best performance occurred with a face in the left visual field (LVF) and a name in the right visual field (RVF), and worst with the opposite configuration, the general pattern of results was incompatible with either a direct access model or an activational/attentional account. The results were, however, most compatible with the predictions of a semispecialized hemispheres account, whereby cerebral asymmetries are seen as relative rather than absolute, either hemisphere being capable of processing either kind of material (verbal or visuospatial), but to different levels of efficiency. However, despite the fact that the stimulus materials had previously been shown to produce stable and consistent lateral asymmetries in the predicted directions when presented in isolation, in the composite, integrative matching task the position of the name seemed to be the major determinant of the resultant asymmetries. It would seem therefore that when such stimuli are to be cross matched, either left hemisphere (language) processes somehow dominate right hemisphere (visuospatial) processing (though not in the way that would be predicted by a simple activational/attentional account) or the left hemisphere's greater capacity predominates.

Discrimination Learning↗
PubMed2003

New insights into the subjective perception of visual field defects.

Most glaucoma patients are unaware of their visual problem until a late stage of the disease, probably because their visual field defects are being filled-in by the brain. According to new insights into how our brain works, plasticity of the visual cortex allows the brain to reorganize after damage to the retina or the visual pathways. This plasticity involves activation of existing but normally ineffective synapses, in a highly organized system of long-range horizontal connections in the visual cortex. Normal cells in the cortex surrounding the lesion thus take control of the deprived ones. As a result, glaucomatous field defects are probably concealed in the colors and patterns of the surround, up to the point where visual input has decreased to such an extent that the brain is not able anymore to compose a plausible image.

Adult↗
PubMed1984

Hemispheric differences in evoked potentials to pictures of faces in the left and right visual fields.

Fifteen right-handed women evaluated the similarity of two faces presented to them either in the left or in the right visual field. The subjects' task was to decide whether the faces were the same or different and accordingly to press a button or abstain from doing so. Errors made by the subjects and the visual evoked potentials (VEPs) from points O1 and O2 referred to point CZ were recorded. Behavioural and electrophysiological results demonstrated the superiority of the right hemisphere in the perception of faces. The subjects made fewer errors when faces were presented in the left visual field. The number of errors also decreased when the presented faces were different from each other. Analysis of the VEPs indicates the existence of hemispheric asymmetry as early as 100 msec after the first stimulus disappeared. The asymmetry is larger in response to the second stimulus. On the basis of these results we conclude that differentiation in hemispheric functions takes place in the phase of short-term memory. The smaller number of errors made when the presented faces were different we explain by the strategy applied by the subjects.

Adult↗
PubMed2026

Risk factors and management strategies for needle disengagement from the visual field in pediatric robot-assisted laparoscopic pyeloplasty.

OBJECTIVE: This study aimed to identify risk factors for suture needle disengagement from the visual field during pediatric robot-assisted laparoscopic pyeloplasty (RALP) and propose effective strategies for prevention and management. METHODS: A retrospective cohort study analyzed clinical data from 339 pediatric patients who underwent RALP for ureteropelvic junction obstruction (UPJO) at a single institution between August 2017 and December 2020. Patients were categorized based on the occurrence of needle disengagement from the visual field. Various patient demographics and surgical procedural factors were evaluated. Univariate and multivariate logistic regression, along with LASSO regression, identified independent risk and protective factors. RESULTS: Needle disengagement occurred in 38 (11.21%) of 339 cases. Multivariate logistic regression identified five independent risk factors for needle disengagement: use of a 3-mm auxiliary trocar (OR = 4.69, 95% CI: 1.98-12.53, P < 0.001), non-standard needle holder use (OR = 2.32, 95% CI: 1.04-5.18, P = 0.038), unshaped suture needles (OR = 3.16, 95% CI: 1.44-7.19, P = 0.005), simultaneous use of &#x2265;2 intra-abdominal sutures (OR = 2.46, 95% CI: 1.15-5.48, P = 0.023), and clamping the needle shank during withdrawal (OR = 3.42, 95% CI: 1.40-8.21, P = 0.006). Conversely, sufficient assistant experience (>10 cases) was identified as a protective factor (OR = 0.39, 95% CI: 0.18-0.88, P = 0.021). CONCLUSION: Suture needle disengagement from the visual field during pediatric RALP is associated with specific technical and instrumental factors. Implementing targeted strategies-such as mandating specialized needle holders, preoperative needle shaping, a single-needle workflow, prioritizing clamping the suture thread over the needle shank during withdrawal, and ensuring adequate assistant training-has the potential to significantly reduce significantly mitigate the risk of needle loss and enhance overall surgical safety in pediatric RALP.

Humans↗