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At least 613 records · Page 34Linked to original sources
PubMed1983

Basic phenomena in acquired colour vision deficiency.

Acquired colour vision defects are directly related to the fixation mode: blue-yellow defects in foveolar fixation, blue-yellow or red-green defects in eccentric fixation. The primary localization of a disease can be retraced from the degree of cone damage. Optic nerve diseases essentially lack signs of cone damage. Processes at the level of the choriocapillaris/retinal pigment epithelium induce a non-selective receptor impairment. There are minor signs of cone damage. In cone dystrophies there is selective cone damage. Scotopization indicates a relatively well-preserved rod function.

Adolescent↗
PubMed1991

Scotopization and the Nagel-II anomaloscope.

The term scotopization refers to the intrusion of rod activity in colour vision when assessed under photopic observation conditions. Scotopization is an important symptom of cone dystrophies. The detection of scotopization is not easy. With the Nagel-II anomaloscope scotopization can be detected in two ways. One method is new and this method is described in the present paper.

Color Perception Tests↗
PubMedDate not supplied

Prevalence of congenital color deficiencies in secondary-school students in Tehran.

PURPOSE: A population-based study was conducted to determine the prevalence of color deficiencies in secondary-school students (ages 12-14) in Tehran. METHODS: A total of 2,058 students (1,136 males, 922 females) were examined with Ishihara pseudoisochromatic color plates. RESULTS: In the study population, 97 cases of defective color vision were detected, including 93 males and 4 females. The affected individuals all had negative histories of previous systemic and ocular disease or chronic use of medications. The visual acuity was 20/20 and the fundus was normal in all affected students. Of the 93 cases of defective color vision in males (8.18%), 56 cases (4.93%) involved deuteranomaly, 13 (1.14%) protanomaly, 13 (1.14%) deuteranopia, and 11 (0.97%) protanopia. The four cases in females (0.43%) involved deuteranomaly in three cases (0.32%) and protanomaly in 1 case (0.11%). Deuteranopia and protanopia were not detected in females. CONCLUSION: This is the first study to determine the prevalence of congenital color blindness in Iran. The results agree with reports of prevalence of congenital color blindness from Western Europe.

Adolescent↗
PubMed1988

Pure homonymous hemiachromatopsia. Findings with neuro-ophthalmologic examination and imaging procedures.

The study describes neuro-ophthalmologic findings in two patients with brain infarction who developed homonymous hemiachromatopsia with resolution to pure homonymous achromatopsia in an upper quadrant. All other visual parameters were normal; only color perimetry was capable of demonstrating the visual disorder. The results are presented with special emphasis on the macular region. Computed tomography studies and magnetic resonance imaging revealed lesions in the caudal and medial occipitotemporal gyri as well as in adjacent cortical regions. The lesions were secondary to disordered circulation in a proximal occipitotemporal branch of the posterior cerebral artery. The anatomical findings and functional relations of color vision in man are discussed in the light of animal findings.

Adult↗
PubMed1993

Influence of pathologic scotopization on the extended Rayleigh match.

Pathologic scotopization, an important symptom of retinal disease, can be studied by means of the Nagel II anomaloscope. This method is called the micro-screw method. The micro-screw method was performed in 14 congenital and 13 acquired colour vision defective individuals. The method proves to be useful in detecting symptoms of rod intrusion in colour vision under photopic conditions.

Color Perception Tests↗
PubMed1994

Pathologic scotopization: a shortened Nagel-II anomaloscopic micro-screw method.

The Nagel-II micro-screw method uses eleven colour equations between 620 and 560 nm. The luminance settings are given and are based on the data of colour normal individuals. In the shortened version, intended to detect pathologic scotopization, it is ascertained at which position of the micro-screw the patient's colour adjustments drop beneath the level of 60 scale Units. A total of 64 patients was examined. 29 congenital colour defectives and 35 acquired colour defectives. With the shortened micro-screw method the patients can be divided into four groups: (1) a group without pathologic scotopization, which includes congenital protan defectives: (2) a group in which pathologic scotopization starts; (3) a group with evident pathologic scotopization, due to Stargardt's disease and other cone dystrophies; and (4) a group with complete pathologic scotopization, which includes the congenital achromats and the end-stages of the cone dystrophies.

Color Perception Tests↗
PubMed1982

Colour vision as a diagnostic aid.

The minimum requirements for a reliable study of (acquired) defects of colour vision have been formulated by Verriest. Taking these minimum requirements as a guide, about 200 patients were selected. For the differential diagnosis of disorders of the retina and the optic nerve the determination of the neutral zone and examination with the anomaloscope are important. This is true for both red-green and blue-yellow defects.

Color Perception Tests↗
PubMed1979

[Detection of dyschromatopsias and professional orientation].

Certain professions necessitate correct recognition of colour in their practice. Early defection of coloured vision abnormalities and professional orientation are therefore very important, especially as it is known that 8 % of the population presents a congenital dyschromatopsy of which one fourth (about 2 %) are serious dyschromatopsies which will prevent the practice of a certain number of professions.

Color Perception Tests↗
PubMed1982

Classification of complete and incomplete autosomal recessive achromatopsia.

We studied color vision in 32 patients with autosomal recessive achromatopsia. Color matching revealed complete achromatopsia (rod monochromasy) in ten patients (Group I) and incomplete achromatopsia in the remaining twenty-two patients. Amongst the incomplete achromats, were three groups distinguishable by their color matching. Patients in Group II were dichromats; their color matches were mediated by rods and MWS (middle-wavelength sensitive) cones. Patients in Groups III and IV were trichromats. Color matches of patients in Group III were mediated by rods, LWS (long-wavelength sensitive) cones and MWS cones. Group III patients showed no evidence of SWS (short-wavelength sensitive) cones. Color matches of patients in Group IV were mediated by rods, LWS cones and SWS cones; color matching did not reveal MWS cones.

Adolescent↗
PubMed1996

Molecular genetics of human color vision.

The significant advances in our understanding of color vision has been due to the convergence of information from behavioral and molecular genetic analyses. The molecular biology of the visual pigments; molecular genetic basis of variation in normal and abnormal color vision, and regulation of the genes at the LWS-MWS pigment gene locus are discussed.

Animals↗