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PubMed1990

Do deviations from radiance-invariance of metameric matches contradict the three pigment theory of foveal trichromacy?

According to the pigment theory of matching, metameric matches result from the equation of the rates of photoisomerizations for each of the three classes of cone pigments excited by the two matched fields. If true, matches are radiance-invariant and additive. Tests of the theory in this paper show small but ubiquitous failures in radiance-invariance due to systematic rather than random errors in matching. A choice between two possible explanations for these systematic errors favors the view that in subjects who deliberately or intuitively search for the middle of the matching range, the errors are due to an asymmetry in the Weber fraction for color (Trezona) at low (but not high) levels of retinal illuminance.

Analysis of Variance↗

PubMed1992

Foveal densitometry in adult-onset diffuse drusen.

We compared the results of foveal densitometry with results of other retinal function tests in five asymptomatic subjects with adult-onset diffuse drusen. All results of routine retinal function tests, including visual acuity, Rayleigh equation color matches, multiple static perimetry, electroretinography, and electro-oculography, were normal. All five subjects had decreased foveal cone photopigment density with densitometry, indicating an early dysfunction at the level of the foveal cone photoreceptors. Several functional defects may be responsible for the densitometric results in adult-onset diffuse drusen, including retinal pigment epithelium dysfunction, foveal cone photoreceptor misalignment, and a reduction of the in situ foveal cone photopigment.

Adult↗

PubMed1981

An ergo-ophthalmological battery of tests to classify truck drivers.

16 healthy and ophthalmologically normal truck drivers are tested with a battery of tests according to the routine described in the following paper. This includes isopter perimetry, colour discrimination, recovery of sensitivity during dark adaptation and refraction at both far and near points, in order to record night myopia as well as night presbyopia. The ranges of individual variability are reported. As far as refraction is concerned, it seems of interest to stress the individual differences in a sort of "transient anisometropia" under incoming twilight.

Accidents, Traffic↗

PubMed1998

Colour vision in normal subjects tested by the colour arrangement test 'Roth 28-hue desaturated'.

The aim of the study was to obtain normal values for the colour-arrangement test, Roth 28-hue desaturated. In 146 healthy non-smokers colour vision was tested monocularly. The subjects were divided into four age groups: 0-19, 20-39, 40-59, and 60-79 years. The overall error score for all groups was 54 +/- 24 (median +/- mean absolute deviation). The values for the 20-39 year group were significantly lower than those for the other groups (Kruskal-Wallis: P < 0.0001 with subsequent multiple Mann-Whitney test). An increasing predominance of errors along the blue-yellow-axis was observed with increasing age. The error scores of normal subjects tested by the Roth 28-hue desaturated were comparable with those on the well-known Farnsworth-Munsell 100-hue (FM-100). Because the Roth 28-hue desaturated is shorter and simpler to administer, it is an alternative to the FM-100 in situations that need to assess colour discrimination and error axis quantitatively and quickly.

Adolescent↗

PubMed1982

Colour association and "colour amnesia" in aphasia.

"Colour association" performance of 50 aphasic patients was investigated by means of a test in which they identified the characteristic colours of objects shown in line drawings. All aphasics with defects in colour association were impaired in reading comprehension. However, some (33%) retained normal aural comprehension. Approximately half the aphasics with receptive language impairment performed normally in colour association. The findings suggest that "colour amnesia" may be the result of a specific cognitive disturbance which is also responsible for a subtype of aphasic alexia.

Adult↗

PubMed1977

Instrumentation for the Farnsworth-Munsell 100-hue test.

Standard Farnsworth-Munsell (F-M) disks and caps are numerically encoded in a two-digit, base-five, system using resistors and zener diodes connected to miniature jack plugs. When the subject orders the disks in the usual way, he connects the plugs to sockets that are in turn connected to an electronic processor. The various error scores are computed, and the error-versus-position graph plotted by a pen recorder, in a total time of between 0.5 and 2.5 min.

Color Perception Tests↗

PubMed1988

Functional anatomy of macaque striate cortex. III. Color.

Using spatially diffuse stimuli (or sinusoidal gratings of very low spatial frequency), levels of 14C-2-deoxy-d-glucose (DG) uptake produced by color-varying stimuli are much greater than those produced by luminance-varying stimuli in macaque striate cortex. Such a difference in DG results is consistent with previous psychophysical and electrophysiological results from man and monkey. In DG experiments with color-varying gratings of low and middle spatial frequencies, or with spatially diffuse color variations, DG uptake was highest in the cytochrome oxidase blobs, as was also seen with low-spatial-frequency luminance gratings. High-spatial-frequency, color-varying uptake patterns were shifted to cover both blob and interblob regions in a manner similar to that of the patterns obtained with middle-spatial-frequency luminance stimuli. However, in no instance did chromatic gratings produce uptake restricted to the interblob regions, as with the pattern seen with the highest-spatial-frequency luminance gratings. Thus, DG uptake is relatively higher in the interblob regions when comparing luminance with color-varying gratings that are otherwise similar. It was also possible to show DG evidence for receptive-field double-opponency in the upper-layer blobs, but color sensitivity in layer 4Cb appears single-opponent. The DG results suggest that color sensitivity is also high in the lower-layer (layers 5 + 6) blobs, and that many layer 5 receptive fields are double-opponent. Striate layers 4Ca and 4B-appeared color-insensitive in a wide variety of DG tests; this supports the idea of a color-insensitive stream running from the magnocellular LGN layers through striate layers 4Ca and 4B to extrastriate areas MT and V3. There was also a major effect due to wavelength: long and short wavelengths produced much more uptake than did middle wavelengths, even when all colors were equated for luminance and saturation. No variation with eccentricity was seen in cortical color sensitivity, at least between 0 degrees and 10 degrees.

Animals↗

PubMed1999

Interindividual variation in human visual performance.

The responses of 20 young adult emmetropes with normal color vision were measured on a battery of visual performance tasks. Using previously documented tests of known reliability, we evaluated orientation discrimination, contrast sensitivity, wavelength sensitivity, vernier acuity, direction-of-motion detection, velocity discrimination, and complex form identification. Performance varied markedly between individuals, both on a given test and when the scores from all tests were combined to give an overall indication of visual performance. Moreover, individual performances on tests of contrast sensitivity, orientation discrimination, wavelength discrimination, and vernier acuity covaried, such that proficiency on one test predicted proficiency on the others. These results indicate a wide range of visual abilities among normal subjects and provide the basis for an overall index of visual proficiency that can be used to determine whether the surprisingly large and coordinated size differences of the components of the human visual system (Andrews, Halpern, & Purves, 1997) are reflected in corresponding variations in visual performance.

Adult↗

PubMed1987

A psychophysical technique for measuring cone photopigment bleaching.

A new, clinically applicable test has been developed to measure the bleaching of the foveal cone photopigments. This noninvasive test is called steady-state color matching. Steady-state color matching is based on the dependence of a color match on the optical density of the cone photopigments. By measuring the color match as a function of retinal illuminance, it is possible to compute the optical density of the cone photopigments at each illuminance. Thus, abnormalities of photopigment bleaching can be detected. This study demonstrates that the technique is readily performed by a clinical population. Patients with central serous retinopathy and retinitis pigmentosa are shown to have low effective optical densities.

Adolescent↗

PubMed1985

Color measurement and discrimination.

Theories of color-difference measurement provide a quantitative means for predicting whether two lights will be discriminable to an average observer. Consider the following color-measurement hypothesis. Suppose that two lights evoke responses from the color channels that we write as vectors, U and U'. The vector difference dU = U - U' is itself a set of channel responses that will result from the presentation of some light. I test the hypothesis that U and U' will be discriminable only if the light that gives rise to their differential, dU, is detectable. In the absence of a luminance component in the difference stimulus, dU, the vector-difference hypothesis holds well. In the presence of a luminance component, the theory is clearly false. When a luminance component is present, discrimination judgements depend largely on whether the lights U and U' are in separate, categorical regions of color space.

Biofeedback, Psychology↗

PubMed1982

Leber's optic neuropathy I. Clinical studies.

A detailed ophthalmological study on 72 individuals at risk to develop Leber's Optic Neuropathy (L.O.N) has revealed that early signs may be present. These included usually non-specific signs such as tortuosity of the peripapillary capillaries as best seen on fluorescein angiography; hyperaemia and a hazy boundary of the disc; relative paracentral and central scotomata; abnormal VERs; and increases in the error score with the Farnsworth 100-Hue test. The only possibly specific sign may be tortuosity of the capillaries. This conclusion was reached by comparing the findings in individuals at risk with the results of examination of five patients seen during the acute phase of L.O.N. One of the persons at risk, who had many early signs, developed L.O.N. 6 months after being studied. In 7 of 13 carriers abnormalities were observed that resembled those seen in certain individuals at risk.

Adolescent↗

PubMed1992

Visual dysfunction without retinitis in patients with acquired immunodeficiency syndrome.

Patients with human immunodeficiency virus infection may have noninfectious and infectious retinopathies, as well as clinical symptoms consistent with optic nerve dysfunction. Noninfectious acquired immunodeficiency syndrome-related retinopathy is seen in most patients with AIDS. Morphologic studies have shown that the number of retrobulbar optic nerve fibers in patients with AIDS is decreased compared to the number of optic nerve fibers in normal control eyes. To determine whether these patients had a visual dysfunction consistent with damage to the macula and optic nerve, 78 subjects (156 eyes) were studied using color-vision and contrast-sensitivity testing. The Farnsworth-Munsell 100-Hue color-vision test was performed on all subjects and age-corrected color-vision scores for all groups were compared. A significant decrease in color discrimination was found in the patients with AIDS (P less than .001). Contrast-sensitivity testing disclosed a deficit of contrast threshold in patients with AIDS at four of five spatial frequencies and in patients with AIDS-related complex at three of the five spatial frequencies examined. This study demonstrated a functional visual deficit in eyes without retinitis consistent with dysfunction of the macula or optic nerve in patients with AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Application of a LaserJet printer to plot the Farnsworth-Munsell 100-hue color test.

This paper presents a quick method of computing Farnsworth-Munsell (FM-100) scores and displaying these values on the polar coordinate scale usually associated with this test. The displayed results also present the clinician with a graph of the extended normalized score against cap number and a D-15 panel plot. The output is printed at high resolution on a Hewlett-Packard (HP) LaserJet or a similar printer compatible with or able to emulate the HP. The program is written and compiled in Microsoft-C 5.0. The code can be easily modified either to be customized, or to be moved across compilers.

Color Perception Tests↗

PubMed1990

Effects of psychological and physical covariates on plasma catecholamines in borderline hypertensives and offspring of hypertensive parents.

The interpretation of plasma catecholamine measurements may be influenced by psychological and physical factors. Therefore, catecholamine concentrations were adjusted for between-subject differences by the following possible confounding factors, i.e. body-mass index, individual maximal physical work capacity, urinary sodium excretion rates and anxiety score. Subjects were 24 borderline essential hypertensives, aged 18-24 years, 50 age-matched normotensive offspring of hypertensive parents and 49 controls with no family history of hypertension studied at rest and during mental stressors (Stroop colour-word conflict test, mental arithmetic). Borderline hypertensives had consistently higher adjusted venous noradrenaline concentrations than control subjects (p less than 0.05). Adjusted plasma adrenaline concentrations were higher in borderline hypertensive subjects than in offspring of hypertensive parents during supine rest. Despite its limitations, venous plasma noradrenaline concentrations when adjusted for work capacity, body-mass, sodium excretion and anxiety suggest enhanced sympatho-neural activity in young borderline essential hypertensives.

Adolescent↗

PubMed1999

[Changes in the mixed salivary indices during orthodontic treatment].

The function of the blood-salivary barrier at different stages of orthodontic treatment of secondary partial adentia depends on the psychoemotional status of a patient. Such a conclusion was made after investigation of mixed human salivary pools. Total sialometry was carried out for objective evaluation of the level of salivary secretion. Salivary secretion was measured and the psychoemotional status of a patient was assessed using M. Luscher's 8-color test. During dental preparation the psychological status was assessed as 21.2 +/- 1.7 scores, versus normal 11.3 +/- 0.03 score. Salivation rate during dental preparation was 1.41 +/- 0.02 ml/min versus normal rate of 0.527 +/- 0.03 ml/min. The results indicate a relationship between psychological reactions of a patient and the manipulations in the oral cavity. These data may be used for assessing the status of a patient in general and, specifically, the stress index.

Adult↗

PubMed1989

Color vision defects in adrenomyeloneuropathy.

The relationship between abnormal color vision and adrenomyeloneuropathy (AMN) was investigated in 27 AMN patients and 31 age-matched controls by using the Farnsworth-Munsell 100 Hue test. Twelve (44%) of 27 patients showed test scores significantly above normal. The axes of bipolarity determined by the testing differed widely between the patients with abnormal scores, compatible with the notion that different alterations in visual pigment genes occur in different AMN kindreds. These observations confirm our earlier impression that the frequency of abnormal color vision is increased in these kindreds, and it supports our contentions that (1) AMN (and its companion, adrenoleukodystrophy) are very closely linked to the visual pigment loci at Xq28 and (2) this proximity might provide the opportunity to observe contiguous gene defects.

Adrenal Gland Diseases↗

PubMed2003

West African crystalline maculopathy.

OBJECTIVE: To describe the findings of a new crystalline maculopathy exclusively affecting elderly members of the Igbo tribe of southeast Nigeria. DESIGN: Retrospective, observational noncomparative case series. METHODS: Six patients referred over a 2-year period to the medical retina consultation service of the King/Drew Medical Center (Los Angeles, Calif) were identified as having a characteristic crystalline maculopathy. Each underwent detailed historical questioning and comprehensive ocular evaluation, including formal retinal examination. Color vision testing, fluorescein angiography, Humphrey visual field analysis, and electrophysiologic assessment were also performed. RESULTS: Each of the 6 patients was an elderly member of the Igbo tribe of southeast Nigeria and demonstrated a unique crystalline maculopathy. A central, superficial cluster of green or yellow, refractile, foveal crystals that were bilateral and asymmetric in distribution was noted in each case. The crystals were benign and unassociated with visual deficit. Retinal sequelae were notably absent and fluorescein angiography results were unremarkable. Additional ancillary testing was generally normal, although 1 patient demonstrated unexplained mild to moderate depression of the scotopic and photopic responses on electrophysiologic analysis. CONCLUSIONS: Elderly members of the Igbo tribe of southeast Nigeria may harbor characteristic bilateral but asymmetric foveal crystals, comprising a novel syndrome of crystalline maculopathy unassociated with obvious visual deficits or retinal sequelae. The etiology of this crystalline maculopathy remains unclear, although genetic, degenerative, and toxic causes are postulated.

Aged↗

PubMed2001

[Change of cone's motion perception in patients with primary open angle glaucoma].

OBJECTIVE: To assess the change of cone's motion perception in primary open angle glaucoma (POAG). METHODS: Equi-luminance random dots moving test was used to determine the change of motion perception of blue, green and red cones in 51 eyes with POAG. To isolate the three kinds of cones, the blue, green and red visual targets were displayed on the yellow, purple and blue-green background respectively. RESULTS: The direction discrimination thresholds of motion perception from blue, green and red cones were all damaged in POAG compared to that of the normal group, and among them the blue cone was the most obviously damaged. CONCLUSIONS: These findings indicate that cone's motion perception, especially the blue cone's, may reveal pre-clinical visual nerve damage in POAG.

Adolescent↗