Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Color Vision”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed1989

X-linked progressive cone dystrophy. Clinical characteristics of affected males and female carriers.

The authors evaluated nine affected males and six female carriers from a four-generation family with X-linked cone dystrophy. As the affected males grew older, visual acuity deteriorated, central scotomas deepened, and macular changes became more prominent. There was granularity of the macula in younger individuals and bull's eye lesions and central geographic atrophy of the retinal pigment epithelium (RPE) in the older subjects. The retinas of some affected males had a bronze-green tapetal-like sheen. Color vision was impaired in all affected males and resembled an acquired type II defect (Verriest classification). One younger subject had paradoxical pupillary constriction to darkness. Visual-evoked potential (VEP) latencies were prolonged in some affected males, suggesting that photoreceptor degeneration caused transsynaptic degeneration of ganglion cells. All female carriers had visual acuities of 20/30 or better, but some showed mild ophthalmoscopic changes and abnormalities of color vision, electroretinograms (ERGs), and VEPs.

Adolescent↗
PubMed1995

[Ocular findings in Desferal therapy].

Desferrioxamine (DFO) is the most important drug in the treatment of thalassemia major and other hematological diseases requiring regular transfusion. It eliminates excessive ferritin by building up chelate complexes. Different mechanisms of possible DFO toxicity are induction of oxidation, damage of the blood-retina barrier, or reduction in other metalloions (Cu2+, Zn2+). The objective of the present study was to evaluate the ocular side effects of DFO treatment. We prospectively examined 17 patients aged 5 to 25 years, all of them treated with DFO. Visual acuity, pupillary reaction, anterior segment, lens and fundus were checked. If possible, visual fields, color vision, dark adaptation, stereoscopic vision, and contrast sensitivity were investigated. Lens opacities were found in 41% (7/17), changes in the retinal pigment epithelium in 35% (6/17), tortuosity of retinal vessels in 24% (4/17), dilation and sheathing of the retinal vessels in 18% (3/17), defects in color vision in 29% (5/17), and abnormal dark adaptation in 18% (3/17) of the patients. The oculotoxicity of DFO is dose-dependent. Major side effects like depression of the visual acuity are partially reversible after discontinuing the therapy. Regular ophthalmological check-ups are therefore necessary.

Adolescent↗
PubMed1980

[Influence of luminous intensity, contrast and color on vision in patients with slight to severe visual defects (author's transl)].

Visual acuity was measured as a function of illuminance (1X; illumination vertical from above) or luminance (cd/m2; illumination of transparent texts from below) for various pathologic alterations of the eye accompanied by a decrease in visual performance (myopia magna with/without retinopathia myopica, astigmatism, senile cataract, aphakia after congenital cataract, macular degeneration, glaucoma etc.) with positive and negative contrast of reading texts. The degree of visual acuity in relation to illuminance or luminance is characteristic for each ocular disease, so that individual adjustment of illumination at the place of work is called for. Visual acuity is not measurably influenced by the color of the light used. Under directed illumination three-dimensional perception is independent of the angle of illumination; under diffuse illumination perception is drastically reduced.

Adolescent↗
PubMed2005

Polymorphic New World monkeys with more than three M/L cone types.

Most New World (platyrrhine) monkeys have M/L cone photopigment polymorphisms that map directly into individual variations in visual sensitivity and color vision. We used electroretinogram flicker photometry to examine M/L cone photopigments in the New World monkey Callicebus moloch (the dusky Titi). Like other New World monkeys, this species has an M/L cone photopigment polymorphism that reflects the presence of X-chromosome opsin gene alleles. However, unlike other platyrrhines in which three M/L photopigments are typical, Callicebus has a total of five M/L cone photopigments. The peak sensitivity values for these pigments extend across the range from 530 to 562 nm. The result is an enhanced array of potential color vision phenotypes in this species.

Animals↗
PubMed1996

[Ophthalmologic findings in patients with sudden deafness].

UNLABELLED: The etiology of sudden hearing loss is still not known. Among other pathomechanisms, vascular disorders have been proposed as an underlying cause. We investigated patients with sudden hearing loss for signs of microcirculation disorders. PATIENTS: Thirty-one patients (15 males and 16 females, mean age 37.5 years) were admitted because of sudden hearing loss. In addition, all patients underwent thorough ophthalmologic examination. RESULTS: Refraction, vision, intraocular pressure and excavation of the optic nerve were normal. In 81% of all cases abnormal conjunctival vascular ectasia were detected. The fundus of 53% of the patients was characterized by slight tortuosity of arterial retinal vessels. The first 11 patients received an ocular electrophysiological examination and showed normal ERG, P-VEP and dark adaptation. Standard perimetry (TAP 2000 ct) revealed no abnormalities in 29 patients, 2 glaucoma patients had small arcuate scotomas. However, 90% of all 29 scotoma-free patients were abnormal in the white-noise campimetry (TEC, Oculus). Testing for color vision (Roth 28 HUE, desat.) revealed abnormally high values (right 120, left 131). CONCLUSION: Although patients with sudden hearing loss appeared healthy in the standard eye examination, the more sensitive tests of white-noise campimetry and color vision, together with the conjunctival vascular ectasia and the tortuosity of arterial retinal vessels, indicated a disturbed microcirculation.

Adult↗
PubMed1978

A general zone theory of color and brightness vision. I. Basic formulation.

A general theory of color and brightness vision, developed from basic principles of the Helmholtz and Hering points-of-view on color vision is presented in a general mathematical form suitable for quantitative analysis. Visual sensation is described by a vector expressed in terms of Hering-like elements for color and brightness which underlie in their spatial-temporal variations the perceptions of form and change. The photic stimulus of vision is recognized to act first and only through photoabsorption producing a Helmholtz-like vector of quantum absorptions. The physiological transformation of the Helmholtz photochemical excitations into the Hering sensation responses is represented as a vector of general operators. The result is a mathematical framework encompassing traditional psychophysical and sensory scaling experiments. The theory is utilized to demonstrate that for many traditional (Class A) psychophysical observations, the physiological operator reduces to a linear (matrix) transformation. For static, uniform, focal stimulation, this reduction is seen to be the basis for earlier specific linear models of color vision. We also illustrate that static intensity-level effects (Bezold-Brücke hue shifts, unique hue invariance) can be modeled from the theory by power, but not logarithmic, intensity-level dependence for the sensation elements.

Color↗
PubMed2004

Separate blue and green cone networks in the mammalian retina.

The distinct absorbance spectra of the cone photopigments form the basis of color vision, but ultrastructural and physiological evidence shows that mammalian cones are electrically coupled. Coupling between cones of the same spectral type should average voltage noise in adjacent photoreceptors and improve the ability to resolve low-contrast spatial patterns. However, indiscriminate coupling between spectral types could compromise color vision by smearing chromatic information across channels. Here we show, by measuring the junctional conductance between green-green and blue-green cone pairs in slices from the dichromatic ground-squirrel retina, that green-green cone pairs are routinely coupled with an average conductance of 220 pS, whereas coupling is undetectable in blue-green cone pairs. Together with a lack of tracer coupling and the selective localization of connexin proteins, our results show that signals in blue and green cones are processed separately in the photoreceptor layer.

Animals↗
PubMed2004

Morphology and functional characteristics in adult vitelliform macular dystrophy.

PURPOSE: Detailed morphologic and functional evaluation of adult vitelliform macular dystrophy (AVMD). METHODS: The records of 61 consecutive AVMD patients (inclusion criterion: vitelliform lesion smaller than one disk diameter at least in one eye) were evaluated retrospectively regarding visual acuity, color vision, perimetry, retinal pigment epithelium (RPE) autofluorescence, fluorescein angiography, electro-oculography, full-field and multifocal electroretinography, and molecular genetic evaluation of the VMD2 and RDS/peripherin genes. RESULTS: The mean age of subjects was 54.6 years. Visual loss was variable (median, 0.6; range, 1.25-0.05). Color vision and visual field were normal in about half of the patients but presented defects with high variability in the remaining patients. Autofluorescence findings showed increased fluorescence within the foveal yellow lesion in 76%. In the majority of eyes, the amplitude of the 30 Hz flicker response of the full-field electroretinogram (72%) and the central P1 amplitude of the multifocal electroretinogram (63%) were reduced. Mutational analyses revealed a potentially disease-associated mutation in the RDS/peripherin gene in one patient. CONCLUSION: AVMD is characterized by late onset, slow progression, good prognosis, and high variability of morphologic and functional abnormalities resulting frequently in misdiagnosis. Autofluorescence findings indicate lipofuscin accumulation in the yellow lesion. Electroretinography revealed a generalized cone system dysfunction with increasing severity toward the fovea.

Adult↗
PubMed1976

Ontogenetic shift of spectral phototactic preferences in anuran tadpoles.

Tadpoles of three species of anurans initially had a midspectrum ("green") preference in laboratory phototactic tests, which was shown experimentally to involve a form of true color vision in one species and probably in the other two as well. During development, the preference shifted to shorter wave-lengths (higher frequencies) until a short-wavelength ("blue") preference predominated in the pre- and postmetamorphic stages and in the adults of six species tested; color vision was involved in all of these stages. The green preference of young tadpoles is ecologically adaptive, in that it directs larvae to green plants that provide food or shelter. Tadpoles observed in a pond congregated heavily in vegetated areas rather than in open water. Spectroradiometric field measurements showed that pond illumination in vegetated areas had a more highly saturated yellow-green spectral dominance compared with a desaturated white illumination in open water. During all ontogenetic stages and as adults, the animals had a preference for high illuminance of white light, which correlates with the high illumination of their habitat. Microspectrophotometric data from Liebman and Entine suggested that the green rods are active receptors in tadpoles, making unlikely Muntz's hypothesis that the ontogenetic shift in spectral preferences is due to premetamorphic maturation of these receptors. However, the visual pigments of all five types of photoreceptors shifted from vitamin A2- to vitamin A1-based chromophores during ontogeny, and the resulting shift in spectral response of the receptors might be related to the spectral shift in phototactic preferences.

Adaptation, Ocular↗
PubMed2003

Peripheral retinal dysfunction in patients taking vigabatrin.

OBJECTIVE: To assess the wide-field multifocal electroretinogram (WF-mfERG) for assessment of retinal function in vigabatrin-treated patients. METHODS: Thirty-two adults who had taken vigabatrin for at least 3 years for localization-related epilepsy underwent WF-mfERG, ERG, logMar visual acuity and color vision evaluation, Humphrey visual field analysis (static perimetry), and funduscopy. The group was matched with a cohort of patients who had never received vigabatrin. Results were compared with a normative data set (120 drug-free controls) with respect to potential bilateral abnormalities in response timing. RESULTS: There were no significant differences between groups in visual acuity or color vision testing. Of the vigabatrin patients, 19 (59%) had bilateral visual field defects compared to none of the controls. Using WF-mfERG, all patients on vigabatrin with visual field defects showed abnormalities (100% sensitivity) and only 2 of the 13 patients without a field defect showed retinal abnormalities (86% specificity). CONCLUSIONS: WF-mfERG may be useful for detecting retinal pathology in patients taking vigabatrin. The majority of previous reports based on subjective testing may have underestimated the prevalence of peripheral retinal toxicity related to the drug.

Adult↗
PubMed2002

Optic nerve sheath meningiomas: visual improvement after stereotactic radiotherapy.

OBJECTIVE: The management of primary optic nerve sheath meningioma (ONSM) is controversial. Surgery often results in postoperative blindness in the affected eye and thus has been abandoned as a treatment option for most patients. When these tumors are left untreated, however, progressive visual impairment ensues, which also leads to blindness. Recently, radiation therapy has gained wider acceptance in the treatment of these lesions. Experience with stereotactic radiotherapy (SRT) in the treatment of ONSMs is limited because of the rare incidence of this tumor. We present a series of patients with ONSM who were treated with SRT. METHODS: Five patients (three women, two men), ranging in age from 40 to 73 years, presented with progressive visual loss with decreased visual field, visual acuity, and color vision affecting six eyes (one patient had tumor involving both optic nerves). One patient also presented with proptosis and diplopia. Five eyes had functional residual vision (range, 20/20 to 20/40), and one eye was completely blind. All five patients were diagnosed clinically and radiographically to have an ONSM. Three were intraorbital, one was intracanalicular as well as intraorbital, and one was a left ONSM extending through the optic foramen into the intracranial space and involving the right optic nerve. The five functional eyes were treated with SRT by use of 1.8-Gy fractions to a cumulative dose of 45 to 54 Gy. RESULTS: Follow-up ranged from 1 to 7 years, and serial magnetic resonance imaging revealed no changes in the size of the tumor in all five patients. Four patients experienced dramatic improvement in visual acuity, visual field, and color vision within 3 months after SRT. One patient remained stable without evidence of visual deterioration or disease progression. None had radiation-induced optic neuropathy. CONCLUSION: SRT may be a viable option for treatment of primary ONSM in patients with documented progressive visual deterioration, and it may be effective in improving or stabilizing remaining functional vision.

Adult↗
PubMed1999

Modelling spatial contrast sensitivity functions for chromatic and luminance-modulated gratings.

We extended our detection model of achromatic spatial vision (Rovamo, J., Mustonen, J., & Näsänen, R. (1994a). Modelling contrast sensitivity as a function of retinal illuminance and grating area. Vision Research, 34, 1301-1314) to colour vision by taking into account the fact that due to the spatio-chromatic opponency of retinal ganglion cells and dorsal lateral geniculate nucleus (dLGN) neurons, equiluminous chromatic gratings are not affected by precortical lateral inhibition. We then tested the extended model by using Mullen's experimental data (Mullen, K. J. (1985). The contrast sensitivity of human color vision to red-green and blue-yellow chromatic gratings. Journal of Physiology, 359, 381-400). The band-pass shape of the spatial contrast sensitivity function for luminance-modulated green and yellow gratings transformed to a low-pass shape, resembling the chromatic spatial contrast sensitivity function for red-green and blue-yellow equiluminous gratings, when the effect of precortical lateral inhibition on grating contrast was computationally removed by dividing luminance contrast sensitivities by spatial frequency (i.e. by af, where a = 1 degree). After the removal of this direct effect of lateral inhibition, there still remained a residual shape difference between the spatial contrast sensitivity functions for chromatic and luminance gratings. It was due to indirect reduction of grating visibility by quantal noise high-pass filtered by precortical lateral inhibition. When this indirect effect of quantal noise was also removed, contrast sensitivity for luminance gratings was about twice the sensitivity for chromatic gratings at all spatial frequencies. This was evidently due to the fact that the chromatic contrast of the equiluminous grating at the opponent stage (Cole, G. R., Hine, T. & McIihagga, W. (1993). Detection mechanisms in L-, M-, and S-cone contrast space. Journal of the Optical Society of America A, 10, 38-51) was about half of the luminance contrast of either of its chromatic component. Thus, if the contrast of the equiluminous chromatic grating were not expressed as the Michelson contrast of one chromatic component grating against its own background (Mullen, K. J. (1985). The contrast sensitivity of human color vision to red-green and blue-yellow chromatic gratings. Journal of Physiology, 359, 381-400) but as chromatic contrast at the opponent stage, contrast sensitivity would be the same for chromatic and luminance gratings.

Color Perception↗
PubMed2003

[Impairment of safety in navigation caused by alcohol: impact on visual function].

BACKGROUND: So far in Germany, no legally binding standards for blood alcohol concentration exist that prove an impairment of navigability. The aim of our interdisciplinary project was to obtain data in order to identify critical blood alcohol limits. In this context the visual system seems to be of decisive importance. MATERIALS AND METHODS: 21 professional skippers underwent realistic navigational demands soberly and alcoholized in a sea traffic simulator. The following parameters were considered: visual acuity, stereopsis, color vision, and accommodation. RESULTS: Under the influence of alcohol (average blood alcohol concentration: 1.08 per thousand ) each skipper considered himself to be completely capable of navigating. While simulations were running, all of the skippers made nautical mistakes or underestimated dangerous situations. Severe impairment in visual acuity or binocular function were not observed. Accommodation decreased by an average of 18% ( p=0.0001). In the test of color vision skippers made more mistakes ( p=0.017) and the time needed for this test was prolonged ( p=0.004). CONCLUSIONS: Changes in visual function as well as vegetative and psychological reactions could be the cause of mistakes and alcohol should therefore be regarded as a severe risk factor for security in sea navigation.

Accidents↗
PubMed2003

Homothorax switches function of Drosophila photoreceptors from color to polarized light sensors.

Different classes of photoreceptors (PRs) allow animals to perceive various types of visual information. In the Drosophila eye, the outer PRs of each ommatidium are involved in motion detection while the inner PRs mediate color vision. In addition, flies use a specialized class of inner PRs in the "dorsal rim area" of the eye (DRA) to detect the e-vector of polarized light, allowing them to exploit skylight polarization for orientation. We show that homothorax is both necessary and sufficient for inner PRs to adopt the polarization-sensitive DRA fate instead of the color-sensitive default state. Homothorax increases rhabdomere size and uncouples R7-R8 communication to allow both cells to express the same opsin rather than different ones as required for color vision. Homothorax expression is induced by the iroquois complex and the wingless (wg) pathway. However, crucial wg pathway components are not required, suggesting that additional signals are involved.

Animals↗
PubMed1994

[Dependence of the sensitivity of the central visual field on hemoglobin-oxygen saturation].

Retinal function is very sensitive to changes in hemoglobin oxygen saturation. Characteristic ophthalmological symptoms of oxygen deficiency are: changes in color perception, visual field defect, eye flickering, reduction of visual acuity, seeing double images, defects in neural image interpretation. To test the dependency of changes in the central visual field sensitivity on different degrees of oxygen saturation, 48 probands (48 monocular tests) 20-50 years of age were examined in the altitude simulation chamber of the Aviation Medicine Institute of German Air Force at zero altitude (= 500 m) and at 10,000 ft (ca. 3,500 m height). Three types of experiments were performed: determination of abnormal quotient using a Heidelberg anomaloscope; determination of changes in color vision by saturated and disaturated panel D-15 test; determination of differences in light sensitivity for white, red, blue and green light by a threshold test using a Humphrey Field Analyzer (640) as perimeter. At zero level (500 m) hemoglobin-oxygen saturation was 97% +/- 1%. At 10,000 ft this value decreased to 83% +/- 3%. Hypoxic hypoxia caused neither significant AQ changes nor did it induce reproducible changes in color vision by the panel D-15 test. However, anoxia resulted in significant (P < 0.01) differences in light sensitivity in phototopic range.

Adult↗
PubMed1996

Deletion in the peripherin/RDS gene in two unrelated Sardinian families with autosomal dominant butterfly-shaped macular dystrophy.

BACKGROUND: Autosomal dominant butterfly-shaped macular dystrophy is associated with different mutations of the peripherin/RDS gene. We studied the phenotype of two families with a novel large deletion in the peripherin/RDS gene. METHODS: Clinical study, fluorescein angiography, color vision testing, automatic perimetry, electrophysiologic studies, and DNA analysis were performed on all the members of the two families. RESULTS: Fundus examination in patients aged 30 to 60 years showed yellow deposits in the macula with a butterfly-shaped pattern. Central choroidal atrophy was present in the older patients only. Macular visual function tests (color vision and central visual field) were abnormal, and electro-oculograms were slightly subnormal in five individuals tested. Electroretinograms and results of dark adaptometry were normal. Linkage analysis with intragenic polymorphic markers and quantitative polymerase chain reaction showed heterozygosity for a large deletion that removed exons 2 and 3 of the peripherin/RDS gene in all affected members of two families. CONCLUSIONS: This deletion escaped detection by direct analysis of amplified exons and was identified by intragenic polymorphic markers analysis, resulting in loss of heterozygosity from affected parents to affected children, and by quantitative polymerase chain reaction. The delineation of the molecular defect associated with the disease in these two families allows us to verify the presence or absence of the disease in clinically unaffected members.

Adolescent↗
PubMed1993

[Apropos of preventive ophthalmologic interventions in the child population of compulsory school age. Authors' experience].

The results are reported of work carried out during the last five years by the Center of Social Ophthalmology, director Prof. G. Scuderi, which is part of the II Division of the Ophthalmologic Clinic of Rome University "La Sapienza" with the object of trying out together with territorial units a model of preventive intervention acting as a filter for specialized university facilities. In other words, already existing facilities and medical personnel were to be used and trained for specific methods and techniques. From 1985 through 1990, 787 children selected by ophthalmologic screening by school doctors among the compulsory school population of the RM 3 and 5 districts were seen and submitted to periodic checks. This cohort included children aged 5 to 14 without significant differences in sex distribution and with prevalence of the 8 to 10 year olds. Each subject was submitted to complete eye examination including refractometry and orthoptics, color vision, biomicroscopic and ophthalmoscopic examination. The principal findings show that about 36% of subjects examined have a natural vision of 11/10 while the high percentage of ametropia observed was mainly represented by astigmatism and hypermetropy, albeit of minor intensity. Strabismus was found in 2.79% and implied marked visual deficit that was often refractory to any type of treatment. In addition, the prevalence was determined of other abnormalities concerning eye motility, color vision and pathologies involving anterior segment and eyeground. In their conclusion, the authors stress the rarity of organic ocular pathology in children (mostly represented by inflammatory changes of the adnexes and conjunctiva) whereas amblyopia was one of the main causes of visual deficit in children. They stress the importance of early therapeutic intervention in order to allow complete visual rehabilitation. The results of the clinical model for prevention were excellent so that it can even be proposed for large scale prevention of amblyopia.

Adolescent↗
PubMed2000

Bilateral simultaneous orbital decompression for Graves' orbitopathy with a combined endoscopic and Caldwell-Luc approach.

Graves' orbitopathy can lead to cosmetic deformity, orbital pain, and visual impairment. Surgical intervention can improve proptosis, cosmetic appearance of the eyelids, vision, and orbital pain with minimal morbidity. Ten patients with dysthyroid orbitopathy underwent concurrent bilateral orbital decompressions. Of these, 9 underwent simultaneous bilateral endoscopic and transantral decompressions, and 1 had only bilateral endoscopic decompressions. Medical management of keratopathy was attempted before surgery. All patients were previously treated with radioiodine and high-dose corticosteroids, and 2 patients had prior low-dose orbital irradiation. Preoperative and postoperative visual acuity, color vision testing, and measurement of proptosis were recorded for all patients. In addition, photographs and CT scans of the orbit and sinuses were done. After surgery, visual acuity improved in 8 patients and remained unchanged in 2 patients. Diplopia in the primary and downward gaze improved in 1 patient and remained unchanged in the 3 others who had it before surgery. Color vision deficits in the blue/yellow range were present in 8 patients before surgery and all reversed within 2 weeks after surgery. Proptosis decreased by an average of 4.83 mm (range 4-7 mm) in patients undergoing the combined decompression and decreased by 4 mm in the 1 patient who had the endoscopic decompression only. Ethmoid sinusitis developed in 1 patient but resolved with oral antibiotics, and another patient had an asymmetric result requiring additional unilateral surgery, which corrected the asymmetry. Overall, this approach avoids external incisions and allows excellent visualization in the regions of the orbital apex and ethmoid roof, facilitating maximal decompression without the increased risk of bleeding or visual disturbances.

Adult↗