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PubMedDate not supplied

Color Doppler ultrasound imaging of the eye and orbit.

Color Doppler imaging is a non-invasive ultrasound procedure which permits simultaneous gray scale imaging of structure and color-coded imaging of blood velocity. This improved technique allows the user to identify even very small blood vessels, such as those supplying the eye, from which measures of blood velocity and vascular resistance can be obtained. In the past five years, color Doppler imaging has found a number of applications in ophthalmology. A common examination procedure and expected normal values have been established, and the technique is becoming routinely employed to evaluate orbital vasculature in some medical centers. Color Doppler imaging has successfully demonstrated changes in orbital hemodynamics associated with a variety of pathological conditions, including central retinal artery and vein occlusions, cranial arteritis, nonarteritic ischemic optic neuropathy, and carotid disease. In addition, the method has been used to detect the vascularization of orbital and ocular tumors, as well as to investigate altered hemodynamics associated with diseases such as glaucoma and diabetic retinopathy.

Eye↗
PubMed2002

[Sexual dimorphism in skin, eye and hair color and the presence of freckles in Chilean teenagers from two socioeconomic strata].

BACKGROUND: The risk of skin cancer is correlated with skin colour. Pigmentation protects against the effects of UV radiation. AIM: To study skin, eyes and hair colour in Chilean teenagers. MATERIAL AND METHODS: The constitutive skin, hair and eyes colour and the presence of freckles was studied in 716 teenagers (416 females) of a low socio economical level and in 307 teenagers (155 females) of a high socio economical level. RESULTS: The proportion of foreign surnames was higher in the high stratum and we only found aboriginal surnames in the low stratum. The females of the lower stratum presented lighter skin than males. This difference was not observed in the higher stratum. We did not find significant differences in the eye colour between sexes, however, adolescents from the high stratum presented lighter eye colour. Females had lighter hair colour than males in both strata, also, we found lighter hair colour in the high stratum. We did not find significant differences in the presence of freckles between strata, but, the proportion of females with freckles was higher than that of males in both strata. CONCLUSIONS: Our results may identify different groups of people, within the Chilean population, with different susceptibility to the effects of ultraviolet radiation.

Adolescent↗
PubMed1997

The color of the human eye: a review of morphologic correlates and of some conditions that affect iridial pigmentation.

Iris color can be affected by a variety of ocular disorders. It is suspected that iris color may not remain constant throughout life. These observations have drawn attention to the morphologic correlates of iris color and its regulation. Differences in the iris color of normal eyes are the result of variable amounts of melanin pigment granules within a constant number of melanocytes in the superficial stroma of the iris. These melanocytes seem to reach their genetically determined amount of melanin in early childhood, and their melanin content usually remains constant in adulthood. Diseases such as Horner's syndrome and Fuchs' heterochromic iridocyclitis affect iris color, resulting in a decrease of iris pigmentation. Evidence suggests that melanin content of some melanocytes is subject to adrenergic regulation even past childhood. Application of the prostaglandin analogue latanoprost, on the other hand, leads to an increase in iris pigmentation in some patients. Studies with cultured dermal and uveal melanocytes, as well as with uveal melanoma cells, however, show no increase in cell proliferation when treated with latanoprost in vitro. The mechanisms by which latanoprost affects regulation of iris pigmentation requires further investigation.

Cell Count↗
PubMed1990

Evaluation of an iris color classification system. The Eye Disorders Case-Control Study Group.

A system for classification of iris color based on standard photographs, developed for use in a multicenter study, is described. Categories of iris color are distinguished based on predominant color (blue, gray, green, light brown, or brown) and the amount of brown or yellow pigment present in the iris. Two trained readers independently graded 339 iris photographs; discrepancies in grades were adjudicated. Measures of interobserver reliability were 0.76 by kappa for exact agreement and 0.97 for weighted kappa. The distribution of iris color grades demonstrates that the system achieved an appropriate level of detail within the authors' study population, which included patients with various racial backgrounds from five urban clinical centers. This simple, reliable classification system for iris color is offered for use in clinical research.

Analysis of Variance↗
PubMed2006

Eye development: random precision in color vision.

In insect and vertebrate eyes, different types of color-detecting photoreceptors are randomly distributed throughout the retina. A recent study has provided important new insights into the developmental mechanisms that generate the retinal mosaic required for color vision.

Animals↗
PubMed1996

Close linkage relationship of the Z-linked pop-eye and silver plumage color loci in the chicken.

The Z-linked pop-eye and the silver plumage color loci in the chicken were tested for linkage using a back cross. The F1 males used were silver, with normal eyes and gold down, pop-eye in coupling (*S *N/*G *POP). The females were gold, pop-eye (*G *POP/W). In previous studies, it had been suggested that both loci were on the short arm of the Z chromosome. There were 13 recombinants among 187 individuals obtained from this mating, indicating that these loci are linked by about 7 cM.

Animals↗
PubMed1995

Color matches in diseased eyes with good acuity: detection of deficits in cone optical density and in chromatic discrimination.

Reduced foveal cone optical density in diseased eyes with normal acuity can affect color matches. Using field diameters of 1 degree, 2 degrees, 4 degrees, and 8 degrees, we measured mean color-match midpoints and match widths in patients who had good acuity and who exhibited three categories of eye disease: hereditary macular degeneration (n = 12), retinitis pigmentosa (n = 19), and glaucoma (n = 18). Results were compared with those for normal observers of comparable ages. Mean color-match midpoints were abnormal only for the population with hereditary macular degeneration, indicating a reduction in cone optical density in the central 4 degrees. Mean color-match widths were enlarged for both hereditary macular degeneration and retinitis pigmentosa, a result consistent with a reduction in the number of foveal cones.

Adult↗
PubMed2005

The nature of infant color categorization: evidence from eye movements on a target detection task.

Infants respond categorically to color. However, the nature of infants' categorical responding to color is unclear. The current study investigated two issues. First, is infants' categorical responding more absolute than adults' categorical responding? That is, can infants discriminate two stimuli from the same color category? Second, is color categorization in infants truly perceptual? Color categorization was tested by recording adults' and infants' eye movements on a target detection task. In Experiment 1, adults were faster at fixating a colored target when it was presented on a colored background from a different color category (between-category) than when it was presented on a colored background from the same color category (within-category), even when within- and between-category chromatic differences were equated in CIE (Committee International d'Eclairage) color space. This category effect was found for two chromatic separation sizes. In Experiment 2, 4-month-olds also responded categorically on the task. Infants were able to fixate the target when the background color was from the same category. However, as with adults, infants were faster at fixating the target when the target background chromatic difference was between-category than when it was within-category. This implies that infant color categorization, like adult color categorization, is truly perceptual.

Adult↗
PubMed1971

Compound eyes: localization of two color receptors in the same ommatidium.

The compound eye of the cockroach Periplaneta has receptors for ultraviolet light (maximum sensitivity at 365 nanometers) and green light (maximum sensitivity at 510 nanometers). Single photoreceptor cells in the compound eye were impaled, identified by spectral response, and marked with dye-filled microelectrodes. Using two diferent dyes, we showed that both types of receptors can be found in the same ommatidium.

Animals↗
PubMed2004

[A neuro-ophthalmological analysis in 80 cases of multiple sclerosis].

We report clinical features of ocular symptoms in 80 patients with multiple sclerosis (MS). Serial 80 patients with MS had been admitted to our Neurology Ward at Nihon University Itabashi Hospital from April 1980 to October 2003. All patients were also examined by our neuro-ophthalmologists. Ocular symptoms were observed in 49 patients, and 14 patients were male and 35 were female. Patients' age at onset varied from 17 to 51 years old, with the average being 31.2 +/- 4.2 years. Observation period were 6 months to15 years, and average 5.4 +/- 1.4 years. In visual symptoms, retrobulbar optic neuritis was observed in 33 eyes of 26 patients. On the first attack of retrobulbar optic neuritis, 25 eyes showed a corrected visual acuity of less than 0.1. After corticosteroid therapy, a corrected visual acuity improved more than 1.0 in 17 eyes. Optic atrophy was observed in 22 eyes and color blindness in 16 eyes. On the second attack of retrobulbar optic neuritis on the same eyes, 6 of 9 eyes showed a corrected visual acuity of less than 0.1 after corticosteroid therapy. Optic atrophy and color blindness were confirmed in all eyes. Homonymous hemianopia was detected in 2 female patients and completely resolved after corticosteroid therapy. On the other hand, ocular motor symptoms were observed in 29 patients. Internuclear ophthalmoplegia was detected in 18 patients, nystagmus in 5, abducens nerve palsy in 5, skew deviation in 5, one-and-a-half syndrome in 2, gaze palsy in 2 and ocular myoclonus in 1. In all except one patient with primary position downbeat nystagmus, ocular myoclonus and bilateral internuclear ophthalmoplegia, these symptoms improved completely within 8 weeks after corticosteroid therapy. We emphasize that cooperation of neurologist and ophthalmologist plays an important role for clinical evaluation of MS patients.

Adolescent↗
PubMed1990

[Luminance contrast and color contrast evoked pattern electroretinogram in normal eyes and in eyes with glaucoma].

Pattern-onset ERGs obtained with color contrast (red-green, blue-yellow) and luminance contrast (green "black") square-wave-stripe patterns (spatial frequency 0.3 c/deg, 32 degree field) were studied in larger groups of normal and glaucomatous (chronic open-angle glaucoma) eyes. Colored stimuli were generated in a two-channel Maxwellian-view system using grating monochromators. In producing isoluminant lights of different colors, the peak latency of the response was used as a criterion. Luminance-contrast responses always have significantly smaller amplitude and shorter peak latency than color-contrast responses. This can be explained by the smaller number and shorter latency of the non-color-coded phasic anglion cells and by the larger number and longer latency of the color-coded tonic cells. Glaucomatous eyes respond with significantly smaller amplitudes at all contrast conditions tested; however, this response reduction is most pronounced with red-green patterns. Peak latencies are not significantly altered in glaucomatous eyes. Since red-green patterns are most appropriate in showing glaucoma damage in the pattern ERG, the largest absolute losses seem to occur among the large red-green antagonistic group of ganglion cells.

Aged↗