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At least 1,621 records · Page 90Linked to original sources
PubMed2001

Distant cancer effects on standardised testing of peripheral vision.

BACKGROUND: Profound central-retinal visual losses have been a major presenting factor reported in cancer and melanoma associated retinopathies (CAR, MAR). However, it is well established that standardised tests of peripheral retinal function are often the most sensitive detectors of early eye disease. This is a preliminary investigation of the responsiveness of the peripheral retina to "distant" (non-eye or CNS) cancers using easily obtained standardised tests. METHODS: The design is a single blind study where test results are compared with published norms and a small age matched control group. Of 120 ambulatory cancer outpatients who were interviewed at routine follow up examinations, 111 volunteered and admitted a range of mild visual changes. 25 cancer patients completed all tests of peripheral vision function and a clinical screening. There were seven control subjects of the same age range. RESULTS: 98% (49 of 50) of eyes from the patient cohort were judged clinically normal following examinations which emphasised the central retina, fundus appearance, and static fields. On testing which emphasised the visual periphery, 46 (92%) eyes showed one or more quantitative abnormalities >2 SD from the age adjusted norm means. These abnormalities clustered mainly about dark adaptation (rod cell) sensitivity (31, 62% of measured sites), the blue sensitive retinal cells (17, 34% of measured eyes), and the oscillatory component (OP) of the electroretinogram (23, 46% of measured eyes). One control eye (7%) showed a significant dark adaptation abnormality and ERG reduction. There was no identifiable interaction between chemotherapy mode and the cancer associated retinal deficits (CARD). Antiretinal antibodies were found in sera from most patients and controls. CONCLUSION: CARD is common in the retinal periphery of many cancer patients, and is distinct from rare CAR, MAR central-retinal responses. CARD has numerous potential clinical uses which justify expanded research with more defined large samples.

Adaptation, Ocular↗
PubMed1989

Contrast sensitivity testing: a more complete assessment of vision.

Contrast sensitivity testing is a powerful tool for determining the capability of the visual system to process spatial and temporal information about the everyday objects we see. The current gold standard in the assessment of vision, visual acuity, provides only a limited amount of information, obtained under artificial conditions. Contrast sensitivity testing measures a range of visual performance under real-life conditions. It measures the least amount of contrast needed to detect a visual stimulus and gives us a more complete quantitization of patients' visual capabilities. Many instances in which losses in contrast sensitivity were detected when visual acuity (one point on the contrast sensitivity function) was normal have been reported. These include amblyopia, neuro-ophthalmology, retina, anterior segment disease, and glaucoma. Therefore, contrast sensitivity testing enables the clinician to diagnose selective deficits in visual processing at an earlier stage than is possible with conventional testing methods.

Amblyopia↗
PubMed1993

A rapid test of rodents' vision using a modified open field apparatus.

Rats' responses to visual change in the environment were recorded in open field arenas in which a part or all of the visual environment could be altered without changing nonvisual features. Rats responded to a change in the appearance of one quadrant of a field by selectively reexploring the changed quadrant, and to a change in the whole environment by generally increasing their locomotor activity. The latter effect was equally large whether the change was from a patterned to a blank environment, or vice-versa. The present paradigms provide a rapid means of testing animals' vision.

Animals↗
PubMed1975

[A railway accident a hundred years ago as reason for systematic testing of colour vision (author's transl)].

Holmgren's supposition that colour blindness was one of the causes for the train-disaster which happened on 15th November 1875 near Lagerlunda had been passed on as an established fact. The course of the accident is outlined on the basis of the court records. It shows that not colour blindness, but the fact that the engine-driver and the station-master were acting contrary to regulations resulted in the head-on collision with the opposite train. After this event systematic testing of colour vision in railway-men was instituted and the methods of examination were considerably improved.

Accidents, Traffic↗
PubMed2002

Reading speed test for potential central vision measurement.

This study examines the validity and reliability of a reading speed test as a measure of potential central vision. Reading speed was calculated in words per minute (wpm) from the time taken to read 30 words of 1.20 logMAR size text. Scores were obtained from subjects with cataract (n = 48), macular disease(n = 35), peripheral vision loss(n = 14) and normal eyes (n = 10). Subjects with macular disease (27.0 +/- 13.2 wpm) read much slower than subjects with cataract (91.9 +/- 13.6 wpm). Little difference was found between subjects with cataract, peripheral vision loss (91.5 +/- 14.7 wpm)and normal eyes (103.8 +/- 15.5 wpm). Repeat testing gave values within +/- 16% of reading speed. These results suggest that a reading speed test using large text could be useful as a potential central vision test in cataract patients.

Aged↗
PubMed1998

Stereoscopic transparency: a test for binocular vision's disambiguating power.

It has been suggested that to resolve ambiguities implicit in binocular perception of complex visual scenes, the brain adopts a continuity constraint assuming that disparities change smoothly with eccentricity. Stereoscopic transparency is characterized by abrupt changes of binocular disparity across retinal locations. The focus of the present study is how the brain uses the continuity constraint in the perception of stereoscopic transparency despite the presence of abrupt disparity changes. Observers viewed random-dot stereograms of overlapping transparent plane and cylindrical surfaces and had to distinguish between two orientations of the cylindrical surface under conditions of strictly controlled depth fixation. Surprisingly, maximal dot density of the transparent plane at which perception is still veridical dramatically decreases as depth separation between the surfaces grows. Persistence of this relationship, when binocular matching processes at each surface are separated to on and off brightness channels, suggests at least two stages in the underlying computation binocular matching and inter-surface interactions. We show that these phenomena cannot be accounted for by either higher severity of matching with high dot densities or the ability of the denser surface to pull vergence to its depth. We also measure contrast sensitivity and near-far symmetry of the underlying mechanism and propose a model of competitive interactions between dissimilar disparities.

Computer Graphics↗
PubMedDate not supplied

Chronic methylmercury exposure in the monkey (Macaca mulatta). Behavioral test of peripheral vision, signs of neurotoxicity, and blood concentration in relation to dose and time.

Small daily doses of methylmercury hydroxide were administered to rhesus monkeys for periods of up to 17 months. Behavioral tests of peripheral vision and of the accuracy and rapidity of hand movements did not disclose any early subtle deficits preceding the onset of obvious signs of neurotoxicity. These signs appeared suddenly and involved reduced food intake (anorexia), clumsiness of jumping, loss of fine control of the digits, and uncoordinated mastication. With a constant daily dose of 0.1 mg/kg or less, blood concentration of mercury reached a peak after about 2 months, and then decreased to about half the peak value. Subsequently, increasing the daily dose level above 0.1 mg/kg (range of 0.12-0.21 mg/kg) produced an increase of blood concentration which tended to stabilize in the range of 2.0-2.5 ppm. After several months at these elevated concentrations all animals exhibited signs of neurotoxicity.

Animals↗
PubMed2004

Is colour vision impairment associated with cognitive impairment in solvent exposed workers?

AIMS: To determine whether acquired colour vision deficits in solvent exposed individuals are associated with cognitive impairment. METHODS: A sample of 82 painters and 38 other subjects were studied. Alcohol, drug, and smoking histories were obtained. Colour vision was tested using the Lanthony D-15-d colour vision test. Cognitive impairment was measured using the Benton visual retention test, Trail making A, and Trail making B tests. Pre-morbid IQ was estimated using the National Adult Reading Test. Solvent exposure in all subjects was estimated using a previously validated, structured subjective assessment methodology. RESULTS: After exclusion of subjects with competing causes of colour vision impairment the final group of men numbered 78. There was a significant association on multiple linear regression between the mean colour confusion index (CCI) and three measures of cognitive impairment, the Benton visual retention test, Trail making A, and Trail making B tests after adjusting for the effects of age (or IQ as appropriate), alcohol, and smoking. CONCLUSION: Acquired colour vision loss is associated with cognitive impairment in solvent exposed workers. However, given the prevalence of acquired colour vision losses in the adult population, colour vision testing is unlikely to be of value as a screening test.

Adult↗
PubMed2000

Impairment of colour vision in workers exposed to organic solvents.

OBJECTIVES: To investigate loss of colour vision related to exposure to solvents and the role of three enzyme polymorphisms in modifying the risk in exposed workers. METHODS: A sample was studied of 68 male dockyard workers and 42 male community controls with and without neuropsychological symptoms from a previous cross sectional study. Indices of cumulative and intensity based exposure to solvents were calculated for all subjects. Alcohol, drug, and smoking histories were obtained. Colour vision was tested by Lanthony D15d colour vision test. Genotype of glutathione S-transferase M1 and T1 and N-acetyltransferase 2 polymorphisms were determined. RESULTS: The relation between impairment of colour vision and exposure to solvents was investigated with multiple regression techniques. Increasing annual exposure to solvents was significantly associated with reduced colour vision (p=0.029). Impairment of colour vision was not associated with neuropsychological symptoms as measured by the Q16 solvent symptom questionnaire. No significant association was found between acquired impairment of colour vision and genetic polymorphisms when GSTM1, GSTT1 or NAT2 phenotypes were included in the analyses. CONCLUSIONS: Exposure to mixed solvents is associated with impairment in colour vision, the risk increases with increasing exposure. The risk of impairment of colour vision was not altered in this study by the presence of different GSTM1, GSTT1 or NAT2 polymorphisms.

Arylamine N-Acetyltransferase↗
PubMedDate not supplied

The influence of vision on computerized neurobehavioral test scores: a proposal for improving test protocols.

Computerized tests of neurobehavioral function are frequently administered in neurotoxicological studies with little attention given to the optical properties of test stimuli or to the vision of subjects. Yet many test stimuli are small or briefly presented, and test endpoints often involve short reaction times. Stimulus detection and reaction time are known to be strongly dependent upon stimulus luminance, contrast, and size, as well as on the subject's visual abilities. The current study assessed the influence of visual contrast sensitivity on Neurobehavioral Evaluation System 2 (NES2) test results in three data sets. Analyses indicated that vision was associated with up to 24% of the variance (Hand Eye Coordination test) in NES2 scores, even when visual acuity was normal, and that vision often influenced the significance of group differences. It is suggested that researchers measure the luminance, contrast, and size of test stimuli, the distance from the subject's eyes to the monitor, and the subject's visual contrast sensitivity. The measurement and control of stimulus parameters and the inclusion of visual function scores in analysis models could reduce the variability among computerized test scores both within and between studies. Models that assess the influence of vision on computerized test results may help to identify the CNS domains and specialized functions adversely affected by neurotoxicant exposures.

Adolescent↗
PubMedDate not supplied

Urine glucose tests for diabetic patients with impaired vision.

A colorimetric test procedure called Mega-Diastix is described for detection and measurement of glucose in urine. The test is designed for use by diabetic patients with imparied vision. Data establishing the performance capabilities of this rapid, convenient test are presented. As an internal standard, the recommended procedure utilizes effervescent control tablets for preparation of simulated urine. Also described is a touch fermentation test for detection of urinary glucose by totally blind patients. Data are given that demonstrate the accuracy and ease of performance of this test, which entails a rapid yeast fermentation. An internal standard is also incorporated into the procedure for this test.

Blindness↗
PubMed1981

[Trial and evaluation of a new test to examine color vision (author's transl)].

With the new Rodenstock color test disk it is possible to distinguish with 99% accuracy between deuteranopia and protanopia. In addition, the diagnosis is quantitatively correct (anomaly or anopia) in 92% of deuteranopia and 98% of protanopia cases. A special scheme for evaluation is presented. Special emphasis was placed on describing exactly the function of this new method of examining inherited color vision deficiencies. Only persons who were already known to have defective color vision were tested. Therefore, no conclusions can be drawn regarding the efficiency of detection of color vision deficiencies.

Color Perception Tests↗