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PubMed2005

Tooth whitening: tooth color changes following treatment by peroxide and light.

OBJECTIVE: This study examined the use of color measurement to determine tooth color in a study of bleaching with peroxide and light used separately and in combination. Two measurement protocols were evaluated for their ability to reveal differences between treatments and confirm tooth shade evaluations. METHODOLOGY: Before and after treatment, 43 subjects were evaluated for tooth color using a shade guide and a chromameter. Two measurement procedures were used: one measured a single location on each tooth using a fabricated plastic stent, and the other measured nine locations across the buccal surface. Values from the two procedures were compared to each other, and to shade guide measurements. RESULTS: Tooth color, as measured by both procedures, significantly correlated with shade evaluation. Statistically significant differences between treatment groups were found more often with data from the multiple-site procedure than from the single-site procedure. Incisal-gingival color gradation on tooth surfaces was diminished as a result of whitening treatments. Chromameter measurement data showed that tooth whitening procedures reduced tooth yellowness (b) more reproducibly than they increased whiteness (L). CONCLUSION: When more sites per surface were measured, tooth color measurement by the chromameter more closely matched shade with less variability and greater statistical power. Chromameter-derived values can be used to estimate shade values to a reasonable level of accuracy. Decreasing yellowness, particularly at the gingival margin, was an important component of the tooth whitening effect. Following tooth whitening, teeth were more uniform in their color, and this may contribute substantially to the subjective patient recognition of whiter teeth.

Adolescent↗

PubMed2006

[The effect of methyl-containing supplements during pregnancy on the phenotypic modification of offspring hair color in rats].

The effect of methyl supplements to the diet of pregnant homozygous (AAHH) female rats with agouti coat color mated with homozygous (aahh) males on the phenotypic modification of the coat color of their heterozygous offspring (AaHh) has been studied. Comparative morphological analysis of the main parameters of hair that determine coat color, including the total length of hairs of different types and the length of the upper black (eumelanin) and light (pheomelanin) parts of awn hairs has been performed. The pattern of pigment granule distribution among hair layers has been analyzed. The melanin content of the hair has been determined using electron spin resonance (ESR). Although all offspring have a typical agouti coat color (alternating black and light portions of hair), 39% of them have a darker coat color than control and other experimental rats have. The main differences between the offspring with darkened and standard coat colors are accounted for by the ratio between the eumelanin and pheomelanin portions of awn hairs. In darkened offspring, this ratio is significantly higher than in control rats. The possible mechanisms of the phenotypic modification of agouti coat color in experimental animals are discussed.

Agouti Signaling Protein↗

PubMed1991

[Color vision defects of macular diseases].

Patients with macular diseases such as x-linked juvenile retinoschisis, cone dystrophy, and age-related macular degeneration were studied regarding color vision defects. In 9 of 15 eyes of patients with x-linked juvenile retinoschisis, blue-yellow defects were demonstrated. In the older patients with this dystrophy, color vision defects were more severe than in younger ones. Fluorescein angiography revealed retinal pigment epithelium (RPE) atrophy at the macular area in these older patients. Therefore, it was suggested that the color vision defects were due to dysfunction of the outer sensory retina, occurring secondarily to the inner sensory retina. In patients with cone dystrophy, all the examined eyes showed severe color vision defects. It was proved that the size of the atrophic lesion which when ophthalmoscopically evaluated was found to have some relationship with the degree of color vision defects. In patients with age-related macular degeneration, most of the examined eyes showed color vision defects. Moreover eyes with soft drusen formation and/or RPE detachment usually showed more severe color vision defects than the eyes with hard drusen formation and/or RPE atrophy.

Adolescent↗

PubMed1988

A quantitative scoring technique for panel tests of color vision.

Panel tests of color vision (eg FM100-Hue test) lack a common quantitative method for the scoring of cap arrangements. We describe a scoring method applicable to all panel tests that makes use of a novel technique to analyze test cap data, namely the calculation of a moment of inertia from the Color Difference Vectors (CDVs) of any arrangement pattern. Using the Farnsworth D-15 panel, as an example, we specify how to determine CDVs and demonstrate the benefits of calculating a moment of inertia for the analysis of these vectors. Moment of inertia analysis yields three factors which quantify cap arrangements: the first is the confusion angle which identifies the type of color defect; the second is the Confusion index (C-index) which quantifies the degree of color loss relative to a perfect arrangement of caps; and the third is the Selectivity index (S-index) which quantifies the amount of polarity or lack of randomness in a cap arrangement. A retrospective study on the result of 53 normal and 66 congenitally color defective observers is reported and provides normative data. We show that the technique differentiates between different types of color defect and provides useful clinical information regarding a loss of color vision. Likewise, a similar observation is made on a smaller sample of FM100-Hue results. A BASIC computer program is provided for anyone wishing to use the technique.

Adolescent↗

PubMed1986

Acquired color vision defects and self monitoring of blood sugar in diabetics.

Color vision defects are common in diabetic patients and may precede visible retinal changes. More severe retinopathy is generally associated with more severe color vision defects. Many diabetics err when making color comparisons using self monitoring techniques. Optometrists can play an important role in diabetes patient management by monitoring color vision defects and making patients aware of problems or potential problems in self monitoring. Care must be taken in color vision evaluation as the most frequent acquired color vision defect in diabetics is a blue-yellow axis defect. Most commonly employed color vision tests are not sensitive in detecting this defect.

Aged↗

PubMed1986

The detection of various color combinations under different chromatic ambient illuminations.

Our purpose was to reveal the effects of ambient illumination color and various foreground/background color pairings on a choice reaction time task performed on a color CRT. Six men and two women with normal color vision served as observers in a four-alternative forced choice procedure. A small (18' visual angle) colored circle appeared in the center of one of the unmarked quadrants of the screen. The observer's task was to respond as quickly as possible to this target by pressing one of four buttons corresponding to its location. We found that target colors that were opponent to the background colors were most quickly detected. Detection was enhanced by maximizing both brightness and chromatic contrast, but brightness contrast was much more effective. Chromatic ambient lighting which was a log unit dimmer than the target luminance had no effect on performance.

Choice Behavior↗

PubMed1986

The use of color in the environment of the elderly to enhance function.

Empirical evidence suggests that the functional level of the institutionalized elderly is favorably affected by enriching the environment with the specific use of color and light. Evidence of the validity of this supposition would form a worthwhile contribution to geriatric rehabilitation by promoting the independence of the elderly in the area of activities of daily living. The quality of literature on the appropriate use of environmental color for an institutionalized geriatric population is limited, being primarily descriptive in nature. In general, visual enhancement by the selective use of color is advocated to minimize the adverse effects of sensory deprivation and to enhance mood, whereas color coding and cueing are directed toward improving function. Faced with a variable literature base and a scarcity of studies that scientifically approach the question of what effect visual enhancement might have on function in the elderly, the authors of this paper are conducting a pilot study with the following objectives: To demonstrate that color cueing (in the form of color contrast applied to key objects in the environment) and increased lighting can enhance the performance of activities of daily living in an institutionalized elderly population. To study the concept that improvement in activities of daily living corresponds with improvement in the patient's mood and feelings of self-worth. To evaluate the effect of color and lighting changes in the environment on various aspects of behavior. It is hypothesized that improvement in behavior will accompany increased functional independence. Thus, we would expect to see a relationship between aspects of behavior and those aspects of mood and activities of daily living currently under investigation.

Aged↗

PubMed1982

Improved color vision testing.

Pseudoisochromatic color vision testing plates have traditionally provided the clinician with screening-type information regarding the color with screening-type information regarding the color vision of patients. The introduction of a variable-color filter, through which the patient views these plates during testing, produces quantifiable results while exploiting the clinical advantages of the color plates. Thus, this approach allows the quick classification and quantification of color vision defects in a clinical setting. The results of this study on 153 subjects show that a variable-color filter combined with a series of traditional pseudoisochromatic plates can be successfully used on patients in a typical ophthalmology clinic to identify normal persons, protanopes, and deuteranopes. The results of the new test correlated well with those of standard tests.

Adult↗

PubMed1996

[Color vision test for detection and evaluation of dyschromatopsia].

METHODS: The color vision test for diagnosis and evaluation of the dyschromatopsias consists of a set of 92 colored test charts of the pseudochromatic type, a lamp and a test report giving a graphic image of the sensitivity to color deficiency. RESULTS: The test makes it possible to identify each neutral zone of all types of dyschromatopsia, places the neutral zone within the color spectrum and establishes its extent according to 6 axes (Protan, Deutan, Tritan, Tetartan, Scotopic and Monochromatic) and 10 levels. The visual sensitivity to color is measured on a 10 point scale, just as visual acuity is. Between a normal sensitivity to color, which is marked 1, and an anopia (i.e complete lack of visual sensitivity to color along one axis), marked 0, there are 9 intermediary levels marked 0.9; 0.8: 0.7; 0.6: 0.5; 0.4; 0.3; 0.2 and 0.1. CONCLUSION: Testing is important for all kinds of eye diseases or common diseases which affect eyesight making possible not only early diagnosis of a disease but also treatment follow-up.

Color Perception Tests↗

PubMed1998

Validity of clinical color vision tests for air traffic control.

BACKGROUND: An experiment on the relationship between aeromedical color vision screening test performance and performance on color-dependent tasks of Air Traffic Control Specialists (ATCS) was replicated to expand the database supporting the job-related validity of 13 FAA-accepted screening tests. METHODS: The original experiment (10) (n = 108), and the replication (n = 136) involved a total of 121 normal trichromats, 31 simple and 44 extreme anomalous trichromats, and 48 dichromats; both protans and deutans were included. The simulations of ATCS color tasks which served as validation criteria were flight progress strips (en route centers), aircraft lights and the Aviation Signal Light indicator (ATC terminal operations), and color weather radar (flight service station and en route center facilities). RESULTS: The validities (Kappa) of aeromedical screening tests ranged from 0.44 to 0.91 for prediction of error-free performance on all color-dependent tasks. CONCLUSIONS: The aeromedical screening tests were generally acceptable in terms of selecting individuals who did not make errors on ATCS color tests, but several tests had high false alarm rates. High job-related validity, in the vicinity of 0.90, was confirmed for several aeromedical color vision tests used for ATCS screening.

Adult↗

PubMed1998

In vivo color stability of resin composite veneers and acrylic resin teeth in removable partial dentures.

OBJECTIVE: The color stability of laboratory-made composite veneers was compared to that of artificial resin teeth under in vivo conditions. METHOD AND MATERIALS: Veneers and resin teeth of removable partial dentures were measured colorimetrically with reflection spectrophotometry; the color changes were characterized in the Commission Internationale d'Eclairage L*a*b* color space. The color was first determined 24 hours after manufacture and again after 6, 12, and 18 months at incisal, cervical, and centrofacial tooth positions. The denture teeth and veneers were measured, cleaned to eliminate the influence of surface discoloration, and measured again at every recall. The food consumption and tooth cleaning habits of the patients were taken into account. RESULTS: In all groups the maximum color changes from the baseline measurement were delta L* = 2.1, delta a* = 0.4, and delta b* = 1.8. The changes in the delta E* values were between 1.0 and 2.5 units. Despite polishing, the delta E* values increased by approximately 0.2 to 0.3 units in relation to the previous measurement with increased wearing time. External discolorations were eliminated by polishing, depending on the type of material; the maximum color change because of polishing was between 0.8 and 2.0 units for delta E*. The resin teeth showed no significant changes in the delta E* values. CONCLUSION: After a wearing period of 18 months, the discolorations of the tested materials were clinically acceptable. The artificial resin teeth showed statistically smaller color changes than did the veneering materials.

Color↗

PubMedDate not supplied

Color-specific enhancement of digital photographs for identification of the extent of cutaneous malignancy.

OBJECTIVES: To introduce the concept of active digital imaging to the literature and to support further investigation by showing the utility of photochromatography in the identification of cutaneous cancer margins METHODS: Digital color images of 10 cutaneous basal cell carcinomas were digitally enhanced to highlight color change in and around each lesion. After the most intense area of tumor coloration was located and sampled, the color was digitally changed to a sharply contrasting color across the entire region, thereby highlighting abnormal areas not readily seen by the unaided eye. The enhanced areas of predicted tumor extent were compared with digital images of the resulting defect after treatment with Mohs micrographic surgery. RESULTS: The extent of tumor was predicted with good accuracy in 5 cases and with fair accuracy in 2 cases and was not determinable in the remaining 2 cases. In no case did photochromatography overestimate the extent of the lesion. CONCLUSIONS: Digital highlighting of color change not readily seen by the unaided eye (photochromatography) can improve identification and localization of cutaneous tumor. Our findings justify further investigation into algorithms for photographic color detection and enhancement in the evaluation of tissue change.

Basal Cell Carcinoma↗

PubMed1996

Melanocytes and iris color. Light microscopic findings.

OBJECTIVE: To systematically evaluate morphologic differences in iris stroma that contribute to clinically perceptible differences in iris color, using immunohistochemical identification of stromal melanocytes and fluorescence microscopy. METHODS: Paraffin-embedded sections from 51 human irides were stained with S100a and fluorescein isothiocyanate. Cells were counted and scored as melanocytes or other. Melanocyte number, proportion, and density were determined for light-colored (blue), medium-colored (hazel) and dark-colored (brown) irides and compared. RESULTS: No statistically significant difference was observed for mean total cellularity or mean melanocyte number among the three color groups. Mean total stromal cell count was 1177 +/- 259 (mean +/- SEM), and mean melanocyte number was 778 +/- 196 per 5-micrometer section. In human irides, 65.9% of the iris stroma is composed of melanocytes. Melanocyte density (number of cells per square millimeter) is not related to iris color. CONCLUSION: The number of melanocytes, the proportion of melanocytes, and iris stromal cellularity are not major contributors to iris color.

Aged↗

PubMed1995

Penetrating injuries of the neck in patients in stable condition. Physical examination, angiography, or color flow Doppler imaging.

BACKGROUND: The initial assessment of penetrating injuries of the neck is controversial, with angiography remaining the gold standard for identifying vascular injuries. Recent reports suggest that physical examination might be an accurate way to evaluate these injuries. Color flow Doppler imaging has been used with promising results to assess extremity injuries, but the role of color flow Doppler imaging in neck injuries has not been studied. OBJECTIVE: To evaluate and compare the roles of physical examination, color flow Doppler imaging, and angiography in the identification and management of penetrating neck injuries. STUDY DESIGN: A prospective study of patients in stable condition with penetrating injuries of the neck. All study patients were examined according to a written clinical protocol and subsequently underwent angiography and color flow Doppler imaging. The sensitivity and specificity of physical examination and color flow Doppler imaging were compared with those of angiography. RESULTS: Eighty-two patients fulfilled the criteria for inclusion in the study. Angiography demonstrated vascular lesions in 11 patients (13.4%), but only two (2.4%) of them required treatment. Serious injuries were detected or suspected during physical examination, but six lesions not requiring treatment were missed. When injuries not requiring treatment were excluded, the sensitivity was 100% and the specificity was 91%. With color flow Doppler imaging, 10 of the 11 injuries were identified, for a sensitivity of 91% and a specificity of 98.6%. The sensitivity and specificity were 100% for clinically important lesions. CONCLUSION: The combination of a careful physical examination and color flow Doppler imaging provides a reliable way to assess penetrating neck trauma and may be a safe alternative to routine contrast angiography.

Adolescent↗

PubMed2005

Demonstration of a genotype-phenotype correlation in the polymorphic color vision of a non-callitrichine New World monkey, capuchin (Cebus apella).

Color-vision polymorphism in New World monkeys occurs because of an allelic polymorphism of the single-copy red-green middle-to-long-wavelength-sensitive (M/LWS) opsin gene on the X chromosome. Because color-vision types can readily be estimated from allelic types of the M/LWS opsin gene, this polymorphic system offers researchers an excellent opportunity to study the association between vision and behavior. As a prerequisite for such studies, genetically determined color-vision types must be concordant with phenotypes determined directly by behavioral criteria (e.g., by a color discrimination test). However, such correlations between genotypes and phenotypes have been studied only for callitrichine species. Using genetic, electrophysiological, and behavioral approaches, we evaluated the color vision of brown capuchin monkeys (Cebus apella), a representative non-callitrichine model animal for physiology and behavior. Two allelic M/LWS opsins-P545 and P530-were identified in the studied captive population. Females had one or both of the alleles, and males had either one. The retinal sensitivity in P530 dichromats was short-wave shifted relative to that in P545 dichromats, whereas that in P530/P545 trichromats was between the two groups. In a discrimination task using Ishihara pseudo-isochromatic plates, P530/P545 trichromats were successful in discriminating stimuli that P530 and P545 dichromats were unable to discriminate. In a food-search task, P530/P545 trichromats were able to locate red targets among green distracters as quickly as among white distracters, whereas both types of dichromats took longer. These results demonstrate the mutual consistency between genotypes and phenotypes of color vision, and provide a solid genetic basis on which the ecology and evolution of color vision can be investigated.

Animals↗

PubMed1987

Preferences of female rhesus monkeys (Macaca mulatta) for infantile coloration.

While developmental researchers have long noted that infants of many mammalian species, including primates, have characteristic physical features, such as a distinctive coat or skin color, and some authors have further suggested that these features serve to elicit caretaking and solicitous behavior, few systematic investigations of the actual salience of such features for adult conspecifics have been carried out to date. The present series of 3 studies sought to determine whether natal coat and/or facial skin coloration might provide desirable visual stimulation for rhesus monkey adult females. In these studies the faces and/or fur of 6-month-old rhesus monkeys were dyed to simulate the normal coloration of rhesus monkey neonates. Adult females varying in parity and rearing history were then tested for their relative preference between these infantile-colored 6-month-olds and both normally colored 6-month-olds and other differentially colored control stimulus monkeys. Results indicated that regardless of parity or rearing history the adult female subjects exhibited consistent preferences for the stimulus animals with neonatal-like reddish-pink facial skin coloration.

Animals↗

PubMed2001

Color characteristics of low-chroma and high-translucence dental resin composites by different measuring modes.

The objective of the described research was the evaluation of the effects of the differences in the color-measuring geometry (SCE, SCI) and the standard illuminant on the color and color change after polymerization and thermocycling of resin composites. White, translucent, and conventional shades of two brands of resin composites were measured before and after polymerization and after thermocycling according to the CIE L*a*b* color scale on a reflection spectrophotometer with SCE and SCI geometry under the standard illuminants A, D65, and C. Under both SCE and SCI modes, the color differences (DeltaE*) of specimens between the values measured under illuminants A and D65 or A and C were larger than those between D65 and C in unpolymerized, polymerized, and thermocycled conditions. With SCE geometry, DeltaE* after polymerization of the white shade group was 8.7-9.8 under D65, and was higher than the conventional shade group (p < 0.05) in both materials. With SCE geometry, DeltaE* between polymerized and thermocycled white, translucent shade was 4.4-7.1 under D65. With SCI geometry, the results were in general agreement with those of SCE mode. After polymerization, DeltaE* measured under illuminant A was generally higher than that under D65 or C (p < 0.01). After thermocycling, the color change was different depending on the color-measuring geometry and standard illuminant.

Barium↗

PubMed2004

Three-dimensional (3D) and 4D color Doppler fetal echocardiography using spatio-temporal image correlation (STIC).

OBJECTIVE: Color Doppler echocardiography is used to visualize three transverse planes: the four-chamber, five-chamber, and three vessels and trachea views. Color Doppler spatio-temporal image correlation (STIC) is a new three-dimensional (3D) technique allowing the acquisition of a volume of data from the fetal heart that is displayed as a cineloop of a single cardiac cycle. The aim of the study was to examine the potential of color Doppler STIC to evaluate normal and abnormal fetal hearts. METHODS: This prospective study included 35 normal fetuses and 27 fetuses with congenital heart defects (CHD) examined between 18 and 35 weeks of gestation. Volume acquisition was achieved by initiating the image capture sequence from the transverse four-chamber view. Volumes were stored for later offline evaluation using a personal computer-based workstation in a multiplanar mode and as spatial volume rendering. RESULTS: Successful acquisition was possible in all 62 cases. The three planes could be demonstrated in 31/35 healthy fetuses and in 24/27 fetuses with CHD. Spatial volume rendering was attempted in 18 fetuses with CHD. In the four normal fetuses with inadequate visualization using color Doppler STIC, the region of interest was perpendicular to the ultrasound beam. In two fetuses with CHD inadequate visualization was related to an enlarged heart in late gestation, in which the entire cardiac volume could not be acquired. The third case was an 18-week fetus with complex CHD and transposed great vessels in which artifacts were related to confluent color signals as a result of low resolution in the reconstructed plane. CONCLUSIONS: STIC in combination with color Doppler ultrasound is a promising new tool for multiplanar and 3D/4D rendering of the fetal heart. Limitations may be found later in gestation in fetuses with large hearts and early in gestation as a result of low discrimination of signals. In addition, insonation perpendicular to the structure of interest does not image color Doppler signals and should be avoided during acquisition.

Cardiac Volume↗