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Progress in Retinal and Eye Research Sep 2014Hereditary cone disorders (CDs) are characterized by defects of the cone photoreceptors or retinal pigment epithelium underlying the macula, and include achromatopsia... (Review)
Review
Hereditary cone disorders (CDs) are characterized by defects of the cone photoreceptors or retinal pigment epithelium underlying the macula, and include achromatopsia (ACHM), cone dystrophy (COD), cone-rod dystrophy (CRD), color vision impairment, Stargardt disease (STGD) and other maculopathies. Forty-two genes have been implicated in non-syndromic inherited CDs. Mutations in the 5 genes implicated in ACHM explain ∼93% of the cases. On the contrary, only 21% of CRDs (17 genes) and 25% of CODs (8 genes) have been elucidated. The fact that the large majority of COD and CRD-associated genes are yet to be discovered hints towards the existence of unknown cone-specific or cone-sensitive processes. The ACHM-associated genes encode proteins that fulfill crucial roles in the cone phototransduction cascade, which is the most frequently compromised (10 genes) process in CDs. Another 7 CD-associated proteins are required for transport processes towards or through the connecting cilium. The remaining CD-associated proteins are involved in cell membrane morphogenesis and maintenance, synaptic transduction, and the retinoid cycle. Further novel genes are likely to be identified in the near future by combining large-scale DNA sequencing and transcriptomics technologies. For 31 of 42 CD-associated genes, mammalian models are available, 14 of which have successfully been used for gene augmentation studies. However, gene augmentation for CDs should ideally be developed in large mammalian models with cone-rich areas, which are currently available for only 11 CD genes. Future research will aim to elucidate the remaining causative genes, identify the molecular mechanisms of CD, and develop novel therapies aimed at preventing vision loss in individuals with CD in the future.
Topics: Animals; Color Vision Defects; Disease Models, Animal; Eye Proteins; Humans; Mutation; Retinal Cone Photoreceptor Cells; Retinal Degeneration
PubMed: 24857951
DOI: 10.1016/j.preteyeres.2014.05.001 -
International Ophthalmology Mar 2020As proven in studies dating back to the eighteenth century, color vision changes may occur early in the course of glaucoma. Our aim was to reevaluate the incidence of...
PURPOSE
As proven in studies dating back to the eighteenth century, color vision changes may occur early in the course of glaucoma. Our aim was to reevaluate the incidence of acquired color vision deficiency in glaucoma patients of the University hospital Zürich by using the Panel D-15 test.
METHODS
Inclusion criteria of the study involved a diagnosis of glaucoma, age equal or greater than 18 years with no upper limit and a best-corrected visual acuity (BCVA) smaller than ≤ 0.7 logMAR. All volunteers were tested twice monocularly for color vision with (1) the Ishihara color plate test and (2) the Farnsworth and Lanthony Panel D-15 test by one examiner (L.B.). Using the Moment of Inertia Method of Vingrys and King-Smith (Investig Ophthalmol Vis Sci 29(1):50-63, 1988), we measured the color defect type (blue-yellow, red-green or non-selective).
RESULTS
One hundred and fifty-one eyes of 87 glaucoma patients were included in this study. Nine eyes showed a deficient result in the Ishihara test, which proves a congenital red-green weakness. Fifty-one (33.8%) eyes showed color vision anomalies in the desaturated test and 24 (15.9%) eyes in the saturated Panel D-15 test. A total of 25.2% and 8.6% of eyes in the desaturated and saturated test were diffuse dyschromatopsia, respectively. The second most prevalent deficiencies were blue-yellow defects with 4.0% and 4.6% of saturated and desaturated results. Just the covariate visual acuity had a significant influence on the Panel D-15 result, whereas other variables like age, sex or intraocular pressure did not show any impact.
CONCLUSION
This study ascertains that the long-known theory of color vision defects in patients with glaucoma is also relevant in our sample of 151 eyes, providing continuity to claims firstly reported many years ago. Despite our results highlighting more diffuse dyschromatopsia than other similar experiments, we have also proven that the tritanomalous defects occur more frequently than other color defects.
Topics: Adult; Aged; Aged, 80 and over; Color Perception Tests; Color Vision; Color Vision Defects; Female; Glaucoma; Humans; Incidence; Intraocular Pressure; Male; Middle Aged; Switzerland; Visual Acuity
PubMed: 31705359
DOI: 10.1007/s10792-019-01218-1 -
Australian Health Review : a... Sep 2016
Topics: Color Vision Defects; Humans; Prejudice
PubMed: 26476553
DOI: 10.1071/AH15161 -
Journal of Visualized Experiments : JoVE Apr 2017Many techniques have been developed to visualize how an image would appear to an individual with a different visual sensitivity: e.g., because of optical or age...
Many techniques have been developed to visualize how an image would appear to an individual with a different visual sensitivity: e.g., because of optical or age differences, or a color deficiency or disease. This protocol describes a technique for incorporating sensory adaptation into the simulations. The protocol is illustrated with the example of color vision, but is generally applicable to any form of visual adaptation. The protocol uses a simple model of human color vision based on standard and plausible assumptions about the retinal and cortical mechanisms encoding color and how these adjust their sensitivity to both the average color and range of color in the prevailing stimulus. The gains of the mechanisms are adapted so that their mean response under one context is equated for a different context. The simulations help reveal the theoretical limits of adaptation and generate "adapted images" that are optimally matched to a specific environment or observer. They also provide a common metric for exploring the effects of adaptation within different observers or different environments. Characterizing visual perception and performance with these images provides a novel tool for studying the functions and consequences of long-term adaptation in vision or other sensory systems.
Topics: Adaptation, Physiological; Aging; Color Perception; Color Perception Tests; Color Vision; Color Vision Defects; Humans; Retina; Visual Cortex
PubMed: 28518063
DOI: 10.3791/54038 -
Ophthalmic Genetics Apr 2018Achromatopsia is an autosomal recessive condition, characterised by reduced visual acuity, impaired colour vision, photophobia and nystagmus. The symptoms can be... (Review)
Review
Achromatopsia is an autosomal recessive condition, characterised by reduced visual acuity, impaired colour vision, photophobia and nystagmus. The symptoms can be profoundly disabling, and there is no cure currently available. However, the recent development of gene-based interventions may lead to improved outcomes in the future. This article aims to provide a comprehensive review of the clinical features of the condition, its genetic basis and the underlying pathogenesis. We also explore the insights derived from animal models, including the implications for gene supplementation approaches. Finally, we discuss current human gene therapy trials.
Topics: Animals; Color Vision Defects; Disease Models, Animal; Genetic Therapy; Humans; Molecular Biology
PubMed: 29303385
DOI: 10.1080/13816810.2017.1418389 -
Ophthalmology Oct 2023
Topics: Humans; Color Vision Defects; Macula Lutea; Electroretinography; Cyclic Nucleotide-Gated Cation Channels
PubMed: 36682978
DOI: 10.1016/j.ophtha.2022.11.001 -
Genes Feb 2023This multicenter study aimed to characterize Korean patients with achromatopsia. The patients' genotypes and phenotypes were retrospectively evaluated. Twenty-one...
This multicenter study aimed to characterize Korean patients with achromatopsia. The patients' genotypes and phenotypes were retrospectively evaluated. Twenty-one patients (with a mean age at the baseline of 10.9 years) were enrolled and followed up for a mean of 7.3 years. A targeted gene panel or exome sequencing was performed. The pathogenic variants of the four genes and their frequencies were identified. and were equally the most prevalent genes: (N = 8, 38.1%), (N = 8, 38.1%), (N = 3, 14.3%), and (N = 2, 9.5%). The degree of functional and structural defects varied among the patients. The patients' age exhibited no significant correlation with structural defects. During the follow-up, the visual acuity and retinal thickness did not change significantly. In -achromatopsia patients, a proportion of patients with a normal foveal ellipsoid zone on the OCT was significantly higher than that of patients with other causative genes (62.5% vs. 16.7%; = 0.023). In -achromatopsia patients, the same proportion was significantly lower than that of patients with other causative genes (0% vs. 58.3%; = 0.003). Korean patients with achromatopsia showed similar clinical features but a higher prevalence of variants than those of other ethnic groups. The retinal phenotypes of the variants were more likely to be worse than those of other genes.
Topics: Humans; Color Vision Defects; Retrospective Studies; Cyclic Nucleotide-Gated Cation Channels; Republic of Korea
PubMed: 36833446
DOI: 10.3390/genes14020519 -
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 -
American Journal of Ophthalmology Sep 2023To assess the safety and efficacy of AAV8-hCARp.hCNGB3 in participants with CNGB3-associated achromatopsia (ACHM). (Clinical Trial)
Clinical Trial
PURPOSE
To assess the safety and efficacy of AAV8-hCARp.hCNGB3 in participants with CNGB3-associated achromatopsia (ACHM).
DESIGN
Prospective, phase 1/2 (NCT03001310), open-label, nonrandomized clinical trial.
METHODS
The study enrolled 23 adults and children with CNGB3-associated ACHM. In the dose-escalation phase, adult participants were administered 1 of 3 AAV8-hCARp.hCNGB3 dose levels in the worse-seeing eye (up to 0.5 mL). After a maximum tolerated dose was established in adults, an expansion phase was conducted in children ≥3 years old. All participants received topical and oral corticosteroids. Safety and efficacy parameters, including treatment-related adverse events and visual acuity, retinal sensitivity, color vision, and light sensitivity, were assessed for 6 months.
RESULTS
AAV8-hCARp.hCNGB3 (11 adults, 12 children) was safe and generally well tolerated. Intraocular inflammation occurred in 9 of 23 participants and was mainly mild or moderate in severity. Severe cases occurred primarily at the highest dose. Two events were considered serious and dose limiting. All intraocular inflammation resolved following topical and systemic steroids. There was no consistent pattern of change from baseline to week 24 for any efficacy assessment. However, favorable changes were observed for individual participants across several assessments, including color vision (n = 6/23), photoaversion (n = 11/20), and vision-related quality-of-life questionnaires (n = 21/23).
CONCLUSIONS
AAV8-hCARp.hCNGB3 for CNGB3-associated ACHM demonstrated an acceptable safety and tolerability profile. Improvements in several efficacy parameters indicate that AAV8-hCARp.hCNGB3 gene therapy may provide benefit. These findings, with the development of additional sensitive and quantitative end points, support continued investigation.
Topics: Humans; Adult; Child; Child, Preschool; Color Vision Defects; Prospective Studies; Cyclic Nucleotide-Gated Cation Channels; Genetic Therapy; Inflammation
PubMed: 37172884
DOI: 10.1016/j.ajo.2023.05.009