[BLOOD GROUPS AND HUMAN GENETICS].
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Results for “Color Vision Defects”
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Acquired colour deficiency in patients with Parkinson's disease.
The blue cone pathway is reported to be affected early in Parkinson's disease (PD) and acquired type three (tritan) defects may occur. Sixty-one patients attending a treatment and rehabilitation centre for PD were examined with clinical colour vision tests. Seven of 13 patients, for whom the diagnosis of PD was equivocal or who had other medical conditions, were identified as having tritan colour deficiency. Results for the remaining 44 PD patients were compared with 40 age matched controls. Ten PD patients (22.7%) had tritan defects. Tritan defects were not found in the control group but performance on some tests was age related. We conclude that clinical tests for tritan colour deficiency are unlikely to be helpful in identifying PD.
Aged↗
Comparison of the incidence of colour blindness between sections of Libyan and Indian populations.
Incidence of Red-Green colour blindness was studied in a Libyan population and was then compared with the same in two samples of Indian population. The incidence of the Red-Green colour defect was found to be 2.209% amongst the males and 0.0% amongst the females in the Libyan study. However, the incidence was only 1.841% amongst the ethnic Libyan males. This incidence was comparable with those reported from other African countries like Congo and Uganda. The incidence of Red-Green colour defect amongst the Indian males was found to be 2.295% while it was 0.840% amongst the Indian females.
Adolescent↗
Screening of red-green defects of colour vision with pseudoisochromatic tests.
Fifty red-green defectives and 100 normal subjects were examined with the second edition of the Boström-Kugelberg (BK II, 1972) series and the Ishihara complete edition (1976) of pseudoisochromatic plates. The results are related to those obtained with the first edition of the Boström-Kugelberg test (BK I, 1944) and the Boström test (II B, 1950) and to the classification of defects obtained with the Nagel anomaloscope. The 50 red-green defectives were originally selected by using a combination of the BK I and II B tests. The normal subjects also, passed this preliminary test, as well as an examination with the Nagel anomaloscope. In the final examinations performed under standardized conditions, three red-green defectives passed both the BK II and the BK I test, while eight defectives passed the Ishihara test. Combination of BK II or BK I test with the Ishihara test does not improve the result. Only one defective (a borderline case of protanomaly) passed the separate II B test. Normal subjects were not classified as colour defectives with any of the four pseudoisochromatic tests used. All normal subjects passed both the BK II and the Ishihara test. Classified as suspected red-green defectives (one misreading made in standardized conditions) were five normal subjects with the II B test and one normal subject with the BK I test. In the second edition of Boström-Kugelberg series, the plates numbered 3, 5, 11, 16 and 18 are clearly less effective than respective plates of the first edition. Only the plates numbered 1 and 10 have markedly improved in the second edition. Red-green defectives made on average 0.54 misreadings per plate in the BK II test as compared with respective 0.62 in BK I, 0.69 in the Ishihara and 0.56 in the II B test.
Color Perception Tests↗
A practical guide for colour-vision examination: report of the Standardization Committee of the International Research Group on Colour-Vision Deficiencies.
There are different types and degrees of colour deficiency and some types of defect occur more frequently than others. Several different techniques are used for examining colour vision and many different tests are available commercially. Clinical tests have three aims: to screen for colour deficiency, to diagnose or classify the type of defect and to grade the severity of the defect. Individual tests do not fulfil all three aims and a test battery is recommended for any detailed colour-vision examination or for giving occupational advice. This paper provides information about congenital and acquired colour-vision defects and lists the principal colour-vision tests. Standardized test methods and viewing conditions are described. The efficiency of each test, for screening, diagnosis and grading is indicated and appropriate test batteries are recommended for different testing requirements.
Color Perception Tests↗
Red-green colour blindness in the Tormes-Alberche Valley (Avila-Central Spain).
A population from a Central Spanish region (Tormes-Alberche Valley) has been investigated for the presence of red-green colour vision defects. A sample of 998 subjects (469 male and 529 female) was analyzed. To identify colour vision defects, Ishihara test plates were used. The red-green colour blindness percentage obtained was 4.69 +/- 0.976% for males (2.13% protan and 2.56% deutan types) and none of the females tested were found to be colour blind. These results are within the variation range of Mediterranean populations and lower than the usual frequencies among non-Mediterranean European samples.
Color Vision Defects↗
[ON DIFFICULTIES IN DIAGNOSING TUMORS OF THE POSTERIOR CRANIAL FOSSA].
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Astrocytoma↗
Proposed protocol for a multi-centre study to compare clinical and trade tests of colour vision in firefighters.
Fire-brigade recruits in the UK have their colour vision screened using the Ishihara test. This is unsatisfactory because it rejects subjects with minor deficiencies in colour vision and does not test for blue defects. The Home Office is currently reviewing its recommendations on visual standards. This paper summarizes defects in colour vision, discusses alternative clinical and trade tests for the fire-brigade, and proposes a multi-centre study to collect data on the performance of fire-brigade recruits in clinical and trade tests.
Clinical Protocols↗
Atypical vitelliform macular dystrophy in a 5-generation family.
Five generations of a family with autosomal dominant atypical vitelliform macular dystrophy (A-VMD) were studied. This dystrophy is similar to autosomal dominant Best's vitelliform dystrophy (B-VMD) but clinically more closely resembles sporadic pseudovitelliform macular degeneration (P-VMD). Of the family members who were 14 years or older 43 (24 females and 19 males) of the 101 at risk (43%) were affected. Vision varied from 20/20 to 20/200. Field defects and tritan colour defects were invariably present only when vision was less than or equal to 20/200, but these defects were sometimes present when vision was good. The electrooculographic studies (LP/DT ratios) in this family were found to be normal or reduced and did not correlate with visual acuity. Minimal retinal findings consisted of macular or extramacular punctate yellow lesions or both in the retinal pigment epithelium, which were hypofluorescent by angiography, and retinal pigment epithelial defects in the temporal nerve fibre bundle, which were hyperfluorescent by angiography. Fluorescein angiographic changes were invariably present when retinal lesions were noted, and this was the most reliable test in identifying genotypically affected family members with minimal phenotypic expression.
Adolescent↗
Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin.
Tritanopia is an autosomal dominant genetic disorder of human vision characterize by a selective deficiency of blue spectral sensitivity. The defect is manifested within the retina and could be caused by a deficiency in function or numbers (or both) of blue-sensitive cone photoreceptors. We have used PCR, denaturing gradient gel electrophoresis, and DNA sequencing of amplified exons to detect in four of nine unrelated tritanopic subjects two different point mutations in the gene encoding the blue-sensitive opsin, each leading to an amino acid substitution. Segregation analysis within pedigrees and hybridization of oligonucleotides specific for each allele to DNA samples from control subjects support the hypothesis that these mutations cause tritanopia. These results complete the genetic evidence for the trichromatic theory of human color vision.
Arginine↗
Long-term macular function in eyes with central serous chorioretinopathy.
BACKGROUND: This study aimed to investigate the long-term effects of central serous chorioretinopathy (CSCR) on macular function. METHODS: Sixty-two eyes of 31 patients were included in this study. All patients were diagnosed with unilateral CSCR at the Retina Unit of the Ophthalmology Department, Trakya University Medical Faculty, and had a post-attack bilateral visual acuity of 6/6 and a follow-up period of a minimum of 6 months. Visual function was assessed using the Amsler grid, 40-hue colour discrimination test, visual field examination by means of Octopus automatic perimeter and Cambridge contrast sensitivity tests. RESULTS: Of the 31 patients, 71% were men and 29% were women, with a mean age of 39.3 +/- 7.6 years. The patients had a mean follow-up period of 50.6 +/- 40.5 months after the acute attack. Metamorphopsia was observed in 67.7% of the cases with CSCR. A colour discrimination defect was found in 48.4% of the CSCR eyes and in 54.8% of the fellow eyes. As compared with the fellow eyes, the mean deviation in the central 10 degrees of visual field was significantly higher (t = 2.9, P = 0.007) and the mean contrast sensitivity score was significantly lower (t = -3.2, P = 0.004) in the CSCR eyes. DISCUSSION: Patients with unilateral CSCR were observed to have long-term bilateral colour discrimination defects, and eyes with clinical CSCR were determined to have central relative scotoma and loss of contrast sensitivity.
Adult↗
Reversible colour vision defects in obstructive jaundice.
The ocular function of 14 non-alcoholic, high icteric patients with recent occlusion of the common bile duct and 3 patients with viral hepatitis with a cholestatic pattern was studied. By means of a colour vision test panel including the Farnsworth-Munsell 100-hue test, 12 patients were initially classified as colour defective with a pattern of acquired colour vision deficiency (ACVD), predominantly of a tritan type. Visual acuity, visual field, slit lamp microscopy, intraocular pressure, ophthalmoscopy and tear secretion tests were normal, and all patients had normal levels of serum vitamin A. Retesting of 4 initially colour defective patients after disappearance of the obstructive jaundice showed a complete normalisation of the ACVD's. It is concluded, that the colour perception in patients with obstructive jaundice is related to the serum bilirubin level, and not to a deficiency of vitamin A.
Adult↗
A method for quantitative scoring of the Farnsworth Panel D-15.
The Farnsworth Dichotomous test or Panel D-15 is used extensively for the evaluation of colour discrimination in congenital and acquired colour vision defects. This qualitative assessment of colour vision defect type and severity is based on the hue confusions which are represented diagrammatically on the Panel D-15 score sheet. This paper presents a new proposal for quantitatively scoring the Panel D-15 based on those hue confusions made by the subject. Such a quantitative score can be used to establish relationships with other visual functions or experimental conditions. The application of the scoring technique to clinical results is illustrated.
Color Perception Tests↗
Analysis of L-cone/M-cone visual pigment gene arrays in females by long-range PCR.
The L-cone/M-cone visual pigment gene arrays were analyzed in a group of 63 Japanese females consisting of 7 applicants for examination of their carrier status, 14 color-deficient females, 6 obligate carriers with no genotypic data available for affected father or sons, and 36 color-normals. The first and the downstream genes, the entire region from the promoter to exon 6, were each amplified very efficiently by the long-range PCR to give products of 15.8 and 14.4 kb, respectively. The products were gel-purified and used as the template in the second PCR for exon 5. The region from intron 4 of the last genes, to the nearest neighbor gene, TEX28, was also efficiently amplified by the long-range PCR and the gel-purified products (27.5 kb) were used as the template in the second PCR for exon 5. The status of the 7 applicants was thought to be 3 non-carriers, 2 protan carriers and 2 deutan carriers. All of the 14 color-deficient females had unusual arrays in which an M gene was present as the first gene, an L gene(s) was present downstream, or a single L gene constituted both of the two arrays. One protanopic subject, A348, had an L gene as one of the first genes. The 6 obligate carriers also had unusual arrays with the exception of the mother of the A187, a male subject with pigment color defect. In the 36 color-normal individuals, 4 had downstream L genes. The long-range PCR method is useful for analysis of the L/M visual pigment genes.
Color Vision Defects↗
PHYSIOLOGICAL EFFECTS OF "HYPNOTIC SUGGESTIONS": A CRITICAL REVIEW OF RECENT RESEARCH; (1960-64).
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Asthma↗
GENE INACTIVATION: THE DISTRIBUTION OF GENE PRODUCTS AMONG POPULATIONS OF CELLS IN HETEROZYGOUS HUMANS.
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Agammaglobulinemia↗
The effect of oral contraceptives on colour vision in diabetic women.
The results of previous studies of the effect of oral contraceptives on visual function have produced discrepancies and have lacked specific restraints on the control and experimental groups. We compared 14 diabetics with normal acuity who were taking oral contraceptives with equivalent diabetic and control groups and used the Pickford-Nicholson anomaloscope and the Farnsworth-Munsell 100-Hue test. Diabetics using oral contraceptives showed a definite trend to increases in tritanomaly and extended red-green matching ranges. When these losses were classified by degree of defect a significantly higher incidence of major defects was found among diabetics on "the pill". Partial correlations for colour variables, duration of diabetes and duration of contraceptive therapy revealed a compounding effect. While subjects using oral contraceptives demonstrated trends toward the extreme scores, these effects were found only in one out of every four users.
Adolescent↗
Evaluation of Kojima-Matsubara color vision test plates: validity in young children.
PURPOSE: We examined a pseudoisochromatic color plate test by Kojima and Matsubara for young children which uses drawings of familiar objects rather than letters or numbers. First, we evaluated the test's efficacy as a color deficiency screener and its validity in classifying the types of color deficiencies by comparing its results with those from the Moreland anomaloscope. Second, we eliminated the chromatic factor and evaluated the functional ability of young children to perform the task by determining how many correct responses were obtained using modified black/white replicas of the test plates. METHODS: Part 1: Twenty color-normal and 13 color-deficient adults were diagnosed and classified with the Ishihara test, Panel D-15 test, and anomaloscope. Subjects were then tested with the Kojima-Matsubara test and result were compared with those from the anomaloscope. Part 2: Fifty children aged 3 to 7 years were tested with modified black/white test plate replicas. The number of correct responses for each plate was determined for five different age groups. RESULTS: Part 1: Among the 20 color-normal subjects, 18 read all 10 plates correctly and 2 subjects missed 1 of the 10. Only 1 of the 13 color-deficient subjects exhibited the expected responses for plates 2 to 6 (used for color deficiency screening). The color-deficient subjects' responses for plates 7 to 10, which are used to classify red-green defects, were varied and only the protanomalous subjects (n = 2) followed the expected response pattern. Part 2: Of the 10 black/white modified plates, only 2 were correctly identified by all 50 children. The other plates had a recognition rate that ranged from 32 to 98%. CONCLUSIONS: Because the response patterns given by most of the color-deficient adult subjects were different from those in the test manual, ambiguous results would occur if the Kojima-Matsubara test were used for color vision screening or the diagnosis of color deficiency. In addition, the difficulty that many of the young children exhibited in identifying the objects in the black/white replica plates suggests that there would be a large number of false positive errors (classifying a color normal as color deficient) when using this test in young children.
Adult↗