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Clinical and Experimental Dermatology Mar 2024
Topics: Humans; Color Vision Defects; Dermatology
PubMed: 37966308
DOI: 10.1093/ced/llad391 -
Stem Cells Translational Medicine Jan 2024Cone cell death is a characteristic shared by various retinal degenerative disorders, such as cone-rod dystrophy, Stargardt disease, achromatopsia, and retinitis...
Cone cell death is a characteristic shared by various retinal degenerative disorders, such as cone-rod dystrophy, Stargardt disease, achromatopsia, and retinitis pigmentosa. This leads to conditions like color blindness and permanently impaired visual acuity. Stem cell therapy focused on photoreceptor replacement holds promise for addressing these conditions. However, identifying surface markers that aid in enriching retinal progenitor cells (RPCs) capable of differentiating into cones remains a complex task. In this study, we employed single-cell RNA sequencing to scrutinize the transcriptome of developing retinas in C57BL/6J mice. This revealed the distinctive expression of somatostatin receptor 2 (Sstr2), a surface protein, in late-stage RPCs exhibiting the potential for photoreceptor differentiation. In vivo lineage tracing experiments verified that Sstr2+ cells within the late embryonic retina gave rise to cones, amacrine and horizontal cells during the developmental process. Furthermore, Sstr2+ cells that were isolated from the late embryonic mouse retina displayed RPC markers and exhibited the capability to differentiate into cones in vitro. Upon subretinal transplantation into both wild-type and retinal degeneration 10 (rd10) mice, Sstr2+ cells survived and expressed cone-specific markers. This study underscores the ability of Sstr2 to enrich late-stage RPCs primed for cone differentiation to a large extent. It proposes the utility of Sstr2 as a biomarker for RPCs capable of generating cones for transplantation purposes.
Topics: Animals; Mice; Mice, Inbred C57BL; Receptors, Somatostatin; Retina; Retinal Cone Photoreceptor Cells; Retinal Degeneration; Stem Cells
PubMed: 37935630
DOI: 10.1093/stcltm/szad073 -
Cortex; a Journal Devoted To the Study... Jan 2024The famous "Piazza del Duomo" paper, published in Cortex in 1978, inspired a considerable amount of research on visual mental imagery in brain-damaged patients. As a...
The famous "Piazza del Duomo" paper, published in Cortex in 1978, inspired a considerable amount of research on visual mental imagery in brain-damaged patients. As a consequence, single-case reports featuring dissociations between perceptual and imagery abilities challenged the prevailing model of visual mental imagery. Here we focus on mental imagery for colors. A case study published in Cortex showed perfectly preserved color imagery in a patient with acquired achromatopsia after bilateral lesions at the borders between the occipital and temporal cortex. Subsequent neuroimaging findings in healthy participants extended and specified this result; color imagery elicited activation in both a domain-general region located in the left fusiform gyrus and the anterior color-biased patch within the ventral temporal cortex, but not in more posterior color-biased patches. Detailed studies of individual neurological patients, as those often published in Cortex, are still critical to inspire and constrain neurocognitive research and its theoretical models.
Topics: Humans; Imagination; Temporal Lobe; Cerebral Cortex; Brain Injuries; Imagery, Psychotherapy; Visual Perception
PubMed: 37926612
DOI: 10.1016/j.cortex.2023.10.002 -
European Journal of Ophthalmology Nov 2023Achromatopsia is an autosomal recessive cone dysfunction syndrome, characterized by absence of color discrimination, low visual acuity, photophobia, and nystagmus....
BACKGROUND
Achromatopsia is an autosomal recessive cone dysfunction syndrome, characterized by absence of color discrimination, low visual acuity, photophobia, and nystagmus. Achromatopsia constitutes a common cause of visual impairment in children, with a prevalence of 1:30,000 worldwide.
OBJECTIVE
To characterize the clinical characteristics of achromatopsia, the main genes causing the disease in our population and the clinical course of the disease, with an emphasis on visual function stability with increasing age.
METHODS
Retrospective study based on medical charts of patients with achromatopsia. Patients were divided into two groups according to their age at last follow-up: older and younger than 10 years. A subset of patients with long term follow-up were analyzed separately, with patients being described in both age groups.
RESULTS
Seventy-six patients were included in the study. The mean age was 14.28 years. Variants in the CNGA3 gene were the most common (73.6%). Clinical characteristics included photophobia (96.2%), nystagmus (93.6%), hypermetropia (72.3%) and strabismus (51.1%). In the large cohort there was no correlation of age with visual acuity ( = 0.129). In the separate subset cohort with long follow-up there was a relative improvement in visual acuity with age ( < 0.001).
CONCLUSIONS
CNGA3 is the main gene associated with achromatopsia in our population (around ∼ 73%), which is in contrast to the distribution worldwide (∼ 25%). Most achromats suffer from photophobia and nystagmus, and the main refractive error is hypermetropia. Achromatopsia's natural course seems to be stationary, and there may even be a slight improvement in visual acuity with time.
PubMed: 37920903
DOI: 10.1177/11206721231212768 -
International Journal of Molecular... Oct 2023This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment...
This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment genes. Materials and Methods: The data of students who underwent routine CVD screening using the Ishihara color test in Kaohsiung, Southern Taiwan were analyzed. Furthermore, the DNA samples of 80 randomly selected females and four obligate carriers were analyzed. The most upstream genes, downstream genes, and the most downstream genes in the red/green pigment gene arrays were amplified separately using polymerase chain reaction (PCR), and exon 5 of each gene was analyzed. The prevalence of congenital red-green CVD in this study was 3.46% in males and 0.14% in females. The PCR analysis of the first gene, downstream gene, and last gene revealed normal patterns in 73 normal cases. Seven unusual patterns were detected in two proton carriers and five deutan carriers. Among the randomly selected females, 8.8% (7/80) were CVD carriers. The prevalence of CVD among male Taiwanese students in this study was 3.46%. Female carriers of congenital CVD can be identified by molecular analysis of the visual pigment genes. The proportion of CVD carriers among the randomly selected females was 8.8%, which was slightly higher than expected and further studies are warranted.
Topics: Humans; Male; Female; Color Vision Defects; Color Perception; Retinal Pigments; Prevalence; Taiwan; Cardiovascular Diseases
PubMed: 37894926
DOI: 10.3390/ijms242015247 -
Journal of Medical Ethics Nov 2023
Topics: Humans; Color; Color Vision Defects; Medicine
PubMed: 37871944
DOI: 10.1136/jme-2023-109634 -
Klinische Monatsblatter Fur... Oct 2023
Topics: Humans; Child; Keratoconus; Color Vision Defects; Dry Eye Syndromes; Uveitis
PubMed: 37871591
DOI: 10.1055/a-2101-7551 -
Indian Journal of Ophthalmology Nov 2023This study aimed to evaluate color perception (CP) changes on Ishihara plates following red-tinted contact lenses in subjects with low vision (LV) from retinal diseases. (Observational Study)
Observational Study
PURPOSE
This study aimed to evaluate color perception (CP) changes on Ishihara plates following red-tinted contact lenses in subjects with low vision (LV) from retinal diseases.
METHODS
A cross-sectional observational study without control involved 84 subjects, aged 20-70 years, having LV from retinal diseases to examine CP changes following wearing red-tinted contact lenses. The subjects viewed Ishihara plates, with each eye separately, before and after wearing red lenses in two categories: "plates 1-21" and "plates 22-25". Change in CP with the use of a red lens was the primary outcome measure.
RESULTS
There was a significant increase in the number of plates read in both categories, that is, plates 1-21 (P = 0.002) and plates 22-25 (P = 0.032), the latter being used to diagnose the red-green defects. Although 70 eyes could read both digits on plates 22-25 and appeared to have normal color vision (CV) at baseline, this number rose to 99 eyes following the use of red-tinted lenses. There was a significant change in the type of CP (red defect/green defect/normal/undefined defect) (P = 0.022) with the application of a red-tinted lens.
CONCLUSIONS
The use of red-tinted lenses caused a significant increase in the number of plates read, increased the number of subjects who appeared normal on plates 22-25, and significantly changed CP of LV subjects. These lenses can be a valuable aid for LV subjects. Although Ishihara plates can diagnose only red-green defects, further studies on CV testing techniques that detect both red-green and blue-yellow CV defects are recommended.
Topics: Humans; Color Perception; Vision, Low; Cross-Sectional Studies; Vision Tests; Color Vision Defects; Retinal Diseases; Color Vision
PubMed: 37870020
DOI: 10.4103/IJO.IJO_2532_22 -
Anesthesia and Analgesia Nov 2023Profound racial and ethnic disparities have been documented in health and health care outcomes in recent decades. Some researchers have erroneously ascribed these...
Profound racial and ethnic disparities have been documented in health and health care outcomes in recent decades. Some researchers have erroneously ascribed these inequities to biological variations, prompting debate as to how, or even if, race and ethnicity should be included as an outcome variable. Color blindness is a racial ideology with roots in constitutional law that posits that equality is best achieved by disregarding the racial and ethnic characteristics of the individual. Color consciousness, in contrast, approaches disparities with the knowledge that experiences related to one's race and ethnicity influence an individual's health and well-being. In this Pro-Con commentary article, we discuss the concept of color blindness and debate its use as an approach in medicine and research.
Topics: Humans; Color Vision Defects; Ethnicity; Consciousness; Research Personnel
PubMed: 37862397
DOI: 10.1213/ANE.0000000000006258 -
Acta Paediatrica (Oslo, Norway : 1992) Feb 2024
Topics: Child; Humans; Color Vision Defects; Schools
PubMed: 37849062
DOI: 10.1111/apa.17010