-
Advances in Experimental Medicine and... 2018A heterogenous group of diseases, progressive cone dystrophy usually begins in the mid-teenage years or later in life. The estimated prevalence is 1 in 30,000-40,000... (Review)
Review
A heterogenous group of diseases, progressive cone dystrophy usually begins in the mid-teenage years or later in life. The estimated prevalence is 1 in 30,000-40,000 individuals. Patients usually present with decreased central vision and a color vision deficit; the visual loss is progressive and often accompanied by day blindness (hemeralopia) and light intolerance (photophobia). Over time, affected individuals develop night blindness and loss of peripheral field. Visual acuity deteriorates to 20/200 or even counting fingers. There is some association between X-linked cone-rod dystrophy (CORD) and high myopia.
Topics: Color Vision Defects; Cone Dystrophy; Cone-Rod Dystrophies; Electroretinography; Genetic Diseases, X-Linked; Humans; Photophobia; Vision Disorders; Visual Acuity
PubMed: 30578485
DOI: 10.1007/978-3-319-95046-4_12 -
Der Ophthalmologe : Zeitschrift Der... Nov 2018Light filters with wavelength-dependent transmission and in particular cut-off or step filters (steep dependence of transmission on wavelength) have a broad optical... (Review)
Review
Light filters with wavelength-dependent transmission and in particular cut-off or step filters (steep dependence of transmission on wavelength) have a broad optical application and are relevant in ophthalmology. This article describes some physical and physiological principles of cut-off filters, discusses the physiological aspects of applications, specifically the not always relevant necessity of blue-reducing filters and the lack of efficacy of color filters with color vision deficiencies.
Topics: Color; Color Vision Defects; Filtration; Humans
PubMed: 29679133
DOI: 10.1007/s00347-018-0703-3 -
Investigative Ophthalmology & Visual... Dec 2019To perform deep phenotyping of subjects with PDE6C achromatopsia and examine disease natural history.
PURPOSE
To perform deep phenotyping of subjects with PDE6C achromatopsia and examine disease natural history.
METHODS
Eight subjects with disease-causing variants in PDE6C were assessed in detail, including clinical phenotype, best-corrected visual acuity, fundus autofluorescence, and optical coherence tomography. Six subjects also had confocal and nonconfocal adaptive optics scanning light ophthalmoscopy, axial length, international standard pattern and full-field electroretinography (ERG), short-wavelength flash (S-cone) ERGs, and color vision testing.
RESULTS
All subjects presented with early-onset nystagmus, decreased best-corrected visual acuity, light sensitivity, and severe color vision loss, and five of them had high myopia. We identified three novel disease-causing variants and provide phenotype data associated with nine variants for the first time. No subjects had foveal hypoplasia or residual ellipsoid zone (EZ) at the foveal center; one had an absent EZ, three had a hyporeflective zone, and four had outer retinal atrophy. The mean width of the central EZ lesion on optical coherence tomography at baseline was 1923 μm. The mean annual increase in EZ lesion size was 48.3 μm. Fundus autofluorescence revealed a central hypoautofluorescence with a surrounding ring of increased signal (n = 5). The mean hypoautofluorescent area at baseline was 3.33 mm2 and increased in size by a mean of 0.13 mm2/year. Nonconfocal adaptive optics scanning light ophthalmoscopy revealed residual foveal cones in only one of two cases. Full-field ERGs were consistent with severe generalized cone system dysfunction but with relative preservation of S-cone sensitivity.
CONCLUSIONS
PDE6C retinopathy is a severe cone dysfunction syndrome often presenting as typical achromatopsia but without foveal hypoplasia. Myopia and slowly progressive maculopathy are common features. There are few (if any) residual foveal cones for intervention in older adults.
Topics: Adolescent; Adult; Child; Color Vision; Color Vision Defects; Cyclic Nucleotide Phosphodiesterases, Type 6; Electroretinography; Eye Proteins; Female; Follow-Up Studies; Forecasting; Humans; Male; Middle Aged; Ophthalmoscopy; Phenotype; Tomography, Optical Coherence; Visual Acuity; Young Adult
PubMed: 31826238
DOI: 10.1167/iovs.19-27761 -
International Ophthalmology May 2021Color vision deficiencies are a group of vision disorders, characterized by abnormal color discrimination. They include red-green color blindness, yellow-blue color... (Review)
Review
BACKGROUND
Color vision deficiencies are a group of vision disorders, characterized by abnormal color discrimination. They include red-green color blindness, yellow-blue color blindness and achromatopsia, among others. The deficiencies are caused by mutations in the genes coding for various components of retinal cones. Gene therapy is rising as a promising therapeutic modality. The purpose of this review article is to explore the available literature on gene therapy in the different forms of color vision deficiencies.
METHODS
A thorough literature review was performed on PubMed using the keywords: color vision deficiencies, gene therapy, achromatopsia and the various genes responsible for this condition (OPN1LW, OPN1MW, ATF6, CNGA3, CNGB3, GNAT2, PDE6H, and PDE6C).
RESULTS
Various adenovirus vectors have been deployed to test the efficacy of gene therapy for achromatopsia in animals and humans. Gene therapy trials in humans and animals targeting mutations in CNGA3 have been performed, demonstrating an improvement in electroretinogram (ERG)-investigated cone cell functionality. Similar outcomes have been reported for experimental studies on other genes (CNGB3, GNAT2, M- and L-opsin). It has also been reported that delivering the genes via intravitreal rather than subretinal injections could be safer. There are currently 3 ongoing human clinical trials for the treatment of achromatopsia due to mutations in CNGB3 and CNGA3.
CONCLUSION
Experimental studies and clinical trials generally showed improvement in ERG-investigated cone cell functionality and visually elicited behavior. Gene therapy is a promising novel therapeutic modality in color vision deficiencies.
Topics: Animals; Color Vision Defects; Cyclic Nucleotide-Gated Cation Channels; Electroretinography; Genetic Therapy; Humans; Mutation; Retinal Cone Photoreceptor Cells
PubMed: 33528822
DOI: 10.1007/s10792-021-01717-0 -
American Journal of Clinical Pathology Oct 2022To learn what color vision-deficient pathologists and cytotechnologists consider their most significant problems and advantages as well as any accommodations.
OBJECTIVES
To learn what color vision-deficient pathologists and cytotechnologists consider their most significant problems and advantages as well as any accommodations.
METHODS
An anonymous online survey developed for practicing pathologists and cytotechnologists regarding their experiences with stains was sent to the members of 4 national societies.
RESULTS
We received 377 responses. Twenty-three people, all men, identified themselves as color vision deficient, with 22 reporting red-green color vision deficiency and 1 reporting uncertain type. Eight pathologists and cytotechnologists indicated that they thought that their color vision deficiency conferred advantages to them, including a greater appreciation of morphology, with less confusion resulting from variations in stain quality or intensity. Nineteen pathologists and cytotechnologists thought that their color vision deficiency conferred disadvantages; the most common disadvantages stated were the identification of eosinophils and acid-fast bacilli. Other difficulties included interpretation of RBCs and nucleoli and sometimes Alcian blue, Brown and Brenn, Congo red, crystal violet, Fite, Giemsa, mucicarmine, periodic acid-Schiff, and fluorescence in situ hybridization stains. Only 2 of the color vision-deficient pathologists and cytotechnologists found digital slides more difficult than glass slides.
CONCLUSIONS
Color vision-deficient pathologists and cytotechnologists report that they have developed approaches to viewing slides that do not compromise their interpretations. Digital pathology may provide several approaches for aiding color vision-deficient pathologists with the interpretation of certain stains.
Topics: Alcian Blue; Color Vision Defects; Congo Red; Gentian Violet; Humans; In Situ Hybridization, Fluorescence; Male; Pathology, Clinical; Periodic Acid
PubMed: 35913114
DOI: 10.1093/ajcp/aqac081 -
Current Eye Research Oct 2018The aim of this study is to report on the results of color vision testing in a European cohort of patients with Usher syndrome (USH). We describe the results in relation... (Comparative Study)
Comparative Study
PURPOSE
The aim of this study is to report on the results of color vision testing in a European cohort of patients with Usher syndrome (USH). We describe the results in relation to Usher type (USH1 and USH2), age and visual acuity.
METHODS AND METHODS
The color vision of 220 genetically confirmed adult USH patients, aged 18-70 years, was analyzed with one of three methods: the Farnsworth D-15 Dichotomous test (D-15) along with the Lanthony desaturated 15 Hue tests (D-15d), the Roth 28-Hue test, or the Ishihara 14-plate test. Visual acuity was measured with either the ETDRS or the SNELLEN charts. The Confusion index, the Selectivity index and the Confusion angle were calculated for the panel tests and used for analysis. The numbers of plates that could not be read were analyzed for the Ishihara test.
RESULTS
For the panel tests, the degree of color loss (Confusion index) is similar in both subtypes of USH, but the polarization of error scores (Selectivity index) is significantly lower in USH1 than USH2, showing more diffuse errors than those found in USH2. There is no significant correlation between logMAR visual acuity and the Confusion or the Selectivity indices. Additionally, we find a significant correlation between patient age and the degree and the polarity of the loss only in USH2. There was no difference between USH1 and USH2 in the results of the Ishihara test.
CONCLUSIONS
The examination of color vision in patients with USH shows a significant difference in the pattern of color vision loss in USH1 and USH2 patients, but not in the severity of the loss. In USH2, we find a correlation between patient age and the degree and the polarity of the loss. These results may be due to differences in the pathogenesis of retinal dystrophy in USH1 and USH2.
Topics: Adolescent; Adult; Aged; Color Perception Tests; Color Vision Defects; Female; Genetic Association Studies; Humans; Male; Middle Aged; Usher Syndromes; Visual Acuity; Young Adult
PubMed: 30012035
DOI: 10.1080/02713683.2018.1501804 -
American Journal of Industrial Medicine Nov 2017Styrene is a chemical used in the manufacture of plastic-based products worldwide. We systematically reviewed eligible studies of occupational styrene-induced... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Styrene is a chemical used in the manufacture of plastic-based products worldwide. We systematically reviewed eligible studies of occupational styrene-induced dyschromatopsia, qualitatively synthesizing their findings and estimating the exposure effect through meta-analysis.
METHODS
PubMed, EMBASE, and Web of Science databases were queried for eligible studies. Using a random effects model, we compared measures of dyschromatopsia between exposed and non-exposed workers to calculate the standardized mean difference (Hedges'g). We also assessed between-study heterogeneity and publication bias.
RESULTS
Styrene-exposed subjects demonstrated poorer color vision than did the non-exposed (Hedges' g = 0.56; 95%CI: 0.37, 0.76; P < 0.0001). A non-significant Cochran's Q test result (Q = 23.2; P = 0.171) and an I of 32.2% (0.0%, 69.9%) indicated low-to-moderate between-study heterogeneity. Funnel plot and trim-and-fill analyses suggested publication bias.
CONCLUSIONS
This review confirms the hypothesis of occupational styrene-induced dyschromatopsia, suggesting a modest effect size with mild heterogeneity between studies.
Topics: Color Vision Defects; Humans; Occupational Diseases; Occupational Exposure; Styrene
PubMed: 28836685
DOI: 10.1002/ajim.22766 -
Cold Spring Harbor Perspectives in... Aug 2014It has been possible to use viral-mediated gene therapy to transform dichromatic (red-green color-blind) primates to trichromatic. Even though the third cone type was... (Review)
Review
It has been possible to use viral-mediated gene therapy to transform dichromatic (red-green color-blind) primates to trichromatic. Even though the third cone type was added after the end of developmental critical periods, treated animals acquired red-green color vision. What happened in the treated animals may represent a recapitulation of the evolution of trichromacy, which seems to have evolved with the acquisition of a third cone type without the need for subsequent modification to the circuitry. Some transgenic mice in which a third cone type was added also acquired trichromacy. However, compared with treated primates, red-green color vision in mice is poor, indicating large differences between mice and monkeys in their ability to take advantage of the new input. These results have implications for understanding the limits and opportunities for using gene therapy to treat vision disorders caused by defects in cone function.
Topics: Animals; Color Vision Defects; Genetic Therapy; Mice; Nerve Net; Neuronal Plasticity; Opsins; Saimiri
PubMed: 25147187
DOI: 10.1101/cshperspect.a017418 -
The National Medical Journal of India 2018Colour vision deficiency (CVD) is a common problem and persons with CVD experience difficulties in daily life, early learning and development, education, choice of... (Review)
Review
Colour vision deficiency (CVD) is a common problem and persons with CVD experience difficulties in daily life, early learning and development, education, choice of careers and work performance. Medical professionals with CVD also report difficulties in everyday tasks, training in medicine and performance of medical duties. However, because of limited evidence, the real impact of CVD on the lives of medical professionals is unclear, especially regarding the practice of medicine by doctors. The nature and severity of CVD, awareness of its impact, personal circumstances and the ability to cope with the deficiency are the major factors that determine the impact of CVD. However, there is a paucity of methodologically sound research on social and psychological aspects of CVD. Currently, early detection, enhancing awareness and offering support are the only proven ways of helping medical professionals with CVD. With the growing emphasis on equality and inclusivity of those with deficiencies, it is desirable to strike a balance between concerns about patient care and the rights of medical professionals with CVD to pursue their careers. Therefore, any future research also needs to focus on psychological aspects of CVD while exploring its impact on a career in medicine.
Topics: Adaptation, Psychological; Career Choice; Color Vision Defects; Humans; Patient Safety; Physicians; Quality of Life; Severity of Illness Index
PubMed: 30829224
DOI: 10.4103/0970-258X.253167 -
Scientific Reports May 2022We set out to develop a simple objective test of functional colour vision based on eye movements made in response to moving patterns. We exploit the finding that while...
We set out to develop a simple objective test of functional colour vision based on eye movements made in response to moving patterns. We exploit the finding that while the motion of a colour-defined stimulus can be cancelled by adding a low-contrast luminance-defined stimulus moving in the opposite direction, the "equivalent luminance contrast" required for such cancellation is reduced when colour vision is abnormal. We used a consumer-grade infrared eye-tracker to measure eye movements made in response to coloured patterns drifting at different speeds. An automated analysis of these movements estimated individuals' red-green equiluminant point and their equivalent luminance contrast. We tested 34 participants: 23 colour vision normal controls, 9 deuteranomalous and 2 protanomalous individuals. We obtained reliable estimates of strength of directed eye movements (i.e. combined optokinetic and voluntary tracking) for stimuli moving at 16 deg/s and could use these data to classify participants' colour vision status with a sensitivity rate of 90.9% and a specificity rate of 91.3%. We conclude that an objective test of functional colour vision combining a motion-nulling technique with an automated analysis of eye movements can diagnose and assess the severity of protanopia and deuteranopia. The test places minimal demands on patients (who simply view a series of moving patterns for less than 90 s), requires modest operator expertise, and can be run on affordable hardware.
Topics: Color Perception; Color Vision; Color Vision Defects; Contrast Sensitivity; Eye Movements; Humans; Motion Perception
PubMed: 35562176
DOI: 10.1038/s41598-022-11152-5