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Ophthalmology. Retina Mar 2024To examine the molecular causes of Schubert-Bornschein (S-B) congenital stationary night blindness (CSNB), clinically characterize in detail, and assess...
OBJECTIVE
To examine the molecular causes of Schubert-Bornschein (S-B) congenital stationary night blindness (CSNB), clinically characterize in detail, and assess genotype-phenotype correlations for retinal function and structure.
DESIGN
Retrospective, longitudinal, single-center case series.
PARTICIPANTS
One hundred twenty-two patients with S-B CSNB attending Moorfields Eye Hospital, United Kingdom.
METHODS
All case notes, results of molecular genetic testing, and OCT were reviewed.
MAIN OUTCOME MEASURES
Molecular genetics, presenting complaints, rates of nystagmus, nyctalopia, photophobia, strabismus, color vision defects and spherical equivalent refraction (SER). Retinal thickness, outer nuclear layer (ONL) thickness, and ganglion cell layer + inner plexiform layer (GCL+IPL) thickness from OCT imaging.
RESULTS
X-linked (CACNA1F and NYX) and autosomal recessive (TRPM1, GRM6, GPR179 and CABP4) genotypes were identified. The mean (± standard deviation) reported age of onset was 4.94 ± 8.99 years. Over the follow-up period, 95.9% of patients reported reduced visual acuity (VA), half had nystagmus, and 64.7% reported nyctalopia. Incomplete CSNB (iCSNB) patients more frequently had nystagmus and photophobia. Nyctalopia was similar for iCSNB and complete CSNB (cCSNB). Color vision data were limited but more defects were found in iCSNB. None of these clinical differences met statistical significance. There was no significant difference between groups in VA, with a mean of 0.46 logarithm of the minimum angle of resolution, and VA remained stable over the course of follow-up. Complete congenital stationary night blindness patients, specifically those with NYX and TRPM1 variants, were more myopic. CACNA1F patients showed the largest refractive variability, and the CABP4 patient was hyperopic. No significant differences were found in OCT structural analysis during the follow-up period.
CONCLUSIONS
Retinal structure in CSNB is stationary and no specific genotype-structure correlates were identified. Visual acuity seems to be relatively stable, with rare instances of progression.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
PubMed: 38522615
DOI: 10.1016/j.oret.2024.03.017 -
Vision Research May 2024EnChroma filters are aids designed to improve color vision for anomalous trichromats. Their use is controversial because the results of lab-based assessments of their...
EnChroma filters are aids designed to improve color vision for anomalous trichromats. Their use is controversial because the results of lab-based assessments of their effectiveness have so far largely failed to agree with positive anecdotal reports. However, the effectiveness of EnChroma filters will vary depending on the conditions of viewing, including whether the stimuli are broadband reflective surfaces or colors presented on RGB displays, whether illumination spectra are broadband or narrowband, the transmission spectra of particular filters, and the cone spectral sensitivity functions of the observer. We created a model of anomalous trichromatic color vision to predict the effects of EnChroma filters on the color signals impaired in anomalous trichromacy. Using the model we varied illumination, filter type and observer cone sensitivity functions, and tested the effect of presenting colors as broadband reflective surfaces or on RGB displays. We also used hyperspectral images to assess the impact of the filters on anomalous trichromats' color vision for natural scenes. Model results predicted that the filters should be broadly effective at enhancing anomalous trichromats' equivalent to L/(L + M) chromatic contrasts under a range of viewing conditions, but are substantially more effective for deuteranomals than for protanomals. The filters are predicted to be more effective for broadband reflective surfaces presented under broadband illuminants than for surfaces presented under narrowband illuminants or for colors presented on RGB displays. Since the potential impacts of contrast adaptation and perceptual learning are not considered in the model, it needs to be empirically validated. Results of empirical tests of the effects of EnChroma filters on deuteranomalous color vision in comparison with model predictions are presented in an accompanying paper (Somers et al., in prep.).
Topics: Humans; Color Perception; Color Perception Tests; Color Vision Defects; Retinal Cone Photoreceptor Cells; Color Vision; Color
PubMed: 38522412
DOI: 10.1016/j.visres.2024.108381 -
BMC Pediatrics Jan 2024Color vision deficiency is a common X-linked genetic disorder affecting the day-to-day lives of individuals, in which school-aged children's academic performance can be...
Color vision deficiency is a common X-linked genetic disorder affecting the day-to-day lives of individuals, in which school-aged children's academic performance can be negatively affected. The aim of this study was to evaluate the prevalence and genotypic frequency of congenital color vision defects (CVD), among primary schoolchildren in Adama, Ethiopia. A school-based cross-sectional study design was used. Students were purposively selected based on their ethnicity but were randomly selected from their sections, resulting in a final sample size estimated at 846 schoolchildren who had received informed consent from their families. Data was gathered using the Ishihara color vision test, 38-plate edition. The result of the study revealed that the total prevalence of CVD was much higher (5.6%) among the male children than that of the females, which was only about 1.79%. The prevalence rates of CVD among the targeted ethnic groups were found to be the highest among Amhara (7.45%) > Oromo (5.00%) > Gurage (2.13%) children, respectively, in descending order. 62.76% of the study subjects were homozygous dominant (AA), followed by those with a heterozygous genotype (Aa) (32.51%), and the remaining 4.73% had recessive (aa) genes.
Topics: Child; Female; Humans; Male; Color Vision Defects; Ethiopia; Cross-Sectional Studies; Prevalence; Genotype; Cardiovascular Diseases
PubMed: 38254053
DOI: 10.1186/s12887-024-04529-0 -
MedRxiv : the Preprint Server For... Dec 2023Multiple Sclerosis (MS) is a neuro-inflammatory disease of the Central Nervous System (CNS) in which the body's immune system attacks and destroys myelin sheath that...
PURPOSE
Multiple Sclerosis (MS) is a neuro-inflammatory disease of the Central Nervous System (CNS) in which the body's immune system attacks and destroys myelin sheath that protects nerve fibers and causes disruption in axonal signal transmission. Demyelinating Optic Neuritis (ON) is often a manifestation of MS and involves inflammation of the optic nerve. ON can cause vision loss, pain and discomfort in the eyes, and difficulties in color perception.In this study, we developed NeuroVEP, a portable, wireless diagnostic system that delivers visual stimuli through a smartphone in a headset and measures evoked potentials at the visual cortex from near the O1, Oz, O2, O9 and O10 locations on the scalp (extended 10-20 system) using custom electroencephalography (EEG) electrodes.
METHODS
Each test session is constituted by a short 2.5-minute full-field visual evoked potentials (ffVEP) test, followed by a 12.5-minute multifocal VEP (mfVEP) test. The ffVEP test evaluates the integrity of the visual pathway by analyzing the P1 (also known as P100) component of responses from each eye, while the mfVEP test evaluates 36 individual regions of the visual field for abnormalities. Extensive signal processing, feature extraction methods, and machine learning algorithms were explored for analyzing the mfVEP responses. The results of the ffVEP test for patients were evaluated against normative data collected from a group of subjects with normal vision. Custom visual stimuli with simulated defects were used to validate the mfVEP results which yielded 91% accuracy of classification.
RESULTS
20 subjects, 10 controls and 10 with MS and/or ON were tested with the NeuroVEP device and a standard-of-care (SOC) VEP testing device which delivers only ffVEP stimuli. In 91% of the cases, the ffVEP results agreed between NeuroVEP and SOC device. Where available, the NeuroVEP mfVEP results were in good agreement with Humphrey Automated Perimetry visual field analysis. The lesion locations deduced from the mfVEP data were consistent with Magnetic Resonance Imaging (MRI) and Optical Coherence Tomography (OCT) findings.
CONCLUSION
This pilot study indicates that NeuroVEP has the potential to be a reliable, portable, and objective diagnostic device for electrophysiology and visual field analysis for neuro-visual disorders.
PubMed: 38234795
DOI: 10.1101/2023.12.26.23300405 -
JCI Insight Jan 2024An arginine to cysteine substitution at amino acid position 203 (C203R) is the most common missense mutation in human cone opsin. Linked to color blindness and blue cone...
An arginine to cysteine substitution at amino acid position 203 (C203R) is the most common missense mutation in human cone opsin. Linked to color blindness and blue cone monochromacy (BCM), C203 is involved in a crucial disulfide bond required for proper folding. It has previously been postulated that expression of mutant C203R cone opsin exerts a toxic effect on cone photoreceptors, similar to some well-characterized missense mutations in rhodopsin that lead to protein misfolding. In this study, we generated and characterized a BCM mouse model carrying the equivalent C203R mutation (Opn1mwC198R Opn1sw-/-) to investigate the disease mechanism and develop a gene therapy approach for this disorder. Untreated Opn1mwC198R Opn1sw-/- cones phenocopied affected cones in human patients with the equivalent mutation, exhibiting shortened or absent cone outer segments and loss of function. We determined that gene augmentation targeting cones specifically yielded robust rescue of cone function and structure when Opn1mwC198R Opn1sw-/- mice were treated at early ages. Importantly, treated cones displayed elaborated outer segments and replenished expression of crucial cone phototransduction proteins. Interestingly, we were unable to detect OPN1MWC198R mutant opsin at any age. We believe this is the first proof-of-concept study exploring the efficacy of gene therapy in BCM associated with a C203R mutation.
Topics: Humans; Animals; Mice; Retinal Cone Photoreceptor Cells; Mutation, Missense; Cone Opsins; Rhodopsin; Color Vision Defects
PubMed: 38060327
DOI: 10.1172/jci.insight.172834 -
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 -
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 -
Investigative Ophthalmology & Visual... Oct 2023Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex...
PURPOSE
Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex is congenitally deprived of visual input, which prompts a fundamental question: is the cortical representation of the central visual field in patients with achromatopsia remapped to take up processing of paracentral inputs? Such remapping might interfere with gene therapeutic treatments aimed at restoring cone function.
METHODS
We conducted a multicenter study to explore the nature and plasticity of vision in the absence of functional cones in a cohort of 17 individuals affected by autosomal recessive achromatopsia and confirmed biallelic disease-causing CNGA3 or CNGB3 mutations. Specifically, we tested the hypothesis of foveal remapping in human achromatopsia. For this purpose, we applied two independent functional magnetic resonance imaging (fMRI)-based mapping approaches, i.e. conventional phase-encoded eccentricity and population receptive field mapping, to separate data sets.
RESULTS
Both fMRI approaches produced the same result in the group comparison of achromatopsia versus healthy controls: sizable remapping of the representation of the central visual field in the primary visual cortex was not apparent.
CONCLUSIONS
Remapping of the cortical representation of the central visual field is not a general feature in achromatopsia. It is concluded that plasticity of the human primary visual cortex is less pronounced than previously assumed. A pretherapeutic imaging workup is proposed to optimize interventions.
Topics: Humans; Color Vision Defects; Retinal Cone Photoreceptor Cells; Cyclic Nucleotide-Gated Cation Channels; Mutation; Visual Cortex
PubMed: 37847226
DOI: 10.1167/iovs.64.13.23 -
BMC Ophthalmology Sep 2023Posterior scleritis is an inflammatory reaction of the sclera that occurs posterior to the ora serrata. The aim of this study was to present a case of posterior...
BACKGROUND
Posterior scleritis is an inflammatory reaction of the sclera that occurs posterior to the ora serrata. The aim of this study was to present a case of posterior scleritis and to analyze choroidal circulatory and structural changes using laser speckle flowgraphy (LSFG) and optical coherence tomography (OCT), respectively.
CASE PRESENTATION
A 64-year-old man presented to our department because of hyperemia of the left eye for one week, diplopia, ocular pain, and distorted vision when looking leftward. At an initial examination, his best-corrected visual acuity was 1.0 Oculi uterque (OU), with mild conjunctival hyperemia oculus dexter (OD) and marked ciliary hyperemia oculus sinister (OS). Color fundus photographs revealed a cluster of choroidal folds extending from the macula to the inferior retinal region OS. Swept-Source OCT showed choroidal thickening OD, and bacillary layer detachment and paracentral middle maculopathy on the paracentral side of the optic nerve papilla, suggesting severe inflammation. Fluorescein angiography showed hyperfluorescence in the optic disc and window defects around the macula OU. Indocyanine green angiography showed mottled choroidal vascular hyperpermeability findings in the late stage. B-mode echography displayed thickening of the posterior wall of the left eye. Orbital magnetic resonance imaging showed the thickened posterior eyeball. The patient was diagnosed with posterior scleritis, and 30 mg of oral prednisolone was then given and tapered off over the next 4 months. The hyperemia and intraocular inflammation resolved after the treatment. The rate of change in macular blood flow assessed by the mean blur rate on LSFG was 20.5% and 20.2% decrease OD and OS, respectively, before and after treatment. The central choroidal thickness showed 8.8% and 37.8% decrease OD and OS, respectively.
CONCLUSION
Posterior scleritis complicated with choroiditis was suggested to show different choroidal circulatory dynamics from those in other choroidal inflammations.
Topics: Male; Humans; Middle Aged; Scleritis; Hyperemia; Choroid; Inflammation; Retina
PubMed: 37726746
DOI: 10.1186/s12886-023-03140-8 -
International Journal of Ophthalmology 2023To determine the prevalence of red-green (RG) color vision deficiency (CVD) in an elderly population and its related factors.
AIM
To determine the prevalence of red-green (RG) color vision deficiency (CVD) in an elderly population and its related factors.
METHODS
This report is a part of the Tehran Geriatric Eye Study: a cross-sectional population-based study that was conducted on the elderly population (≥60y) of Tehran, Iran using multi-stage stratified random cluster sampling. All study participants underwent complete ocular examination, including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy. The color vision was tested using Ishihara plates with the near optical correction in place.
RESULTS
Of the 3791 invitees, 3310 participated in the study. The data of 2164 individuals were analyzed after applying the exclusion criteria. The prevalence of R-G CVD was 3.73% (95%CI: 2.37%-5.09%) in the whole sample; the prevalence of protanomaly, protanopia, and deuteranopia was 1.51%, 1.76%, and 0.45%, respectively. The prevalence of R-G CVD was significantly higher in males than in females. The prevalence of RG CVD increased with advancing age from 2.91% in the age group 60-64y to 5.8% in the age group ≥80y (=0.070). According to the multiple logistic regression model, male sex, and glaucoma were significantly related to RG CVD. Older age and hypertension also had a marginally significant relationship with RG CVD.
CONCLUSION
Changes in color vision occur in the elderly due to the aging process and some physiological and pathological factors. Since the change in visual perception may affect the person's performance, this aspect of the visual system's function should also be taken into consideration in the examinations of the elderly.
PubMed: 37724279
DOI: 10.18240/ijo.2023.09.22