Color Vision Research Articles

Long-term exposure to prometryn damages the visual system and changes color preference of female zebrafish (Danio rerio)

Color vision, initiated from the cone photoreceptors, is essential for fish to obtain environmental information. Although the visual impairment of triazine herbicide prometryn has been reported, data on the effect of herbicide such as prometryn on natural color sensitivity of fish is scarce. Here, zebrafish were exposed to prometryn (0, 1, 10, and 100 μg/L) from 2 h post-fertilization to 160 days post-fertilization, to explore the effect and underlying mechanism of prometryn on color perception. The results indicated that 10 and 100 μg/L prometryn shortened the height of red-green cone cells, and down-regulated expression of genes involved in light transduction pathways (arr3a, pde6h) and visual cycle (lrata, rpe65a); meanwhile, 1 μg/L prometryn increased all-trans-retinoic acid levels in zebrafish eyes, and up-regulated the expression of genes involved in retinoid metabolism (rdh10b, aldh1a2, cyp26a1), finally leading to weakened red and green color perception of female zebrafish. This study first clarified how herbicide such as prometryn affected color vision of a freshwater fish after a long-term exposure from both morphological and functional disruption, and its hazard on color vision mediated-ecologically relevant tasks should not be ignored.

Functional and structural neuroretinal disorders in HIV Controllers. Prospective cohort study.

To estimate the prevalence and cumulative incidence of neuro-retinal-disorders (NRD) in HIV-controllers. Prospective, single-centre, cohort study of people living with HIV (PLWH): elite-controllers, long-term-non-progressors and early diagnosed. The study compared "HIV-controllers" (including elite-controllers and long-term-non-progressors), who were not on antiretroviral therapy (ART), and "HIV-treatment" (HIV-infected subjects with a recent diagnosis and on ART). A matched cohort of "non-HIV subjects" was created. NRD was defined as at least one altered (not normal) ophthalmological parameter (functional or structural). Functional (visual acuity, contrast sensitivity, chromatic vision, visual field) and structural parameters (ganglion cells, macular nerve fibre layer, peripapillary nerve fibre layers, vascular calibre) as well as quality of life (Medical Outcomes Study-HIV Short Form-30) were assessed. Between March 2012 and November 2015, the study included all HIV-controllers (16 elite-controllers, 1 long-term-non-progressor), 11 HIV-treatment and 16 non-HIV. Prevalence of NRD at baseline was 88.2% (15/17, 95% CI: 65.7%-96.7%), 90.9% (10/11, 95% CI: 62.3%-98.4%) and 56.3% (9/16, 95% CI: 33.2%-76.9%), respectively. Cumulative incidence at 3 years was 50% (1/2), 100% (1/1) and 33.3% (2/6), respectively. None of the participants manifested ocular clinical symptoms. Three years later, prevalence of NRD was 92.3% (12/13, 95% CI: 66.7%-98.6%), 75% (6/8, 95% CI: 40.9%-92.9%) and 50.0% (7/14, 95% CI: 26.8%-73.2%), respectively. Contrast sensitivity and structural parameters were globally the most affected among PLWH. Quality of life (total score) [median (interquartile range)] at baseline and 3 years was 82 (71-89) and 74 (63.5-79.25) in HIV-controllers and 80 (73-88) and 88 (83-92) in HIV-treatment. HIV-controllers and those individuals on ART presented a higher percentage of NRD than non-HIV. Our results suggest that NRD could be a biomarker of ocular aging among PLWH.

FMRI and gene therapy in adults with CNGB3 mutation

Achromatopsia is an inherited retinal disease that affects 1 in 30,000–50,000 individuals and is characterised by an absence of functioning cone photoreceptors from birth. This results in severely reduced visual acuity, no colour vision, marked sensitivity to light and involuntary oscillations of the eyes (nystagmus). In most cases, a single gene mutation prevents normal development of cone photoreceptors, with mutations in the CNGB3 or CNGA3 gene being responsible for ∼80 % of all patients with achromatopsia. There are a growing number of studies investigating recovery of cone function after targeted gene therapy. These studies have provided some promise for patients with the CNGA3 mutation, but thus far have found limited or no recovery for patients with the CNGB3 mutation. Here, we developed colour-calibrated visual stimuli designed to isolate cone photoreceptor responses. We combined these with adapted fMRI techniques and pRF mapping to identify if cortical responses to cone-driven signals could be detected in 9 adult patients with the CNGB3 mutation after receiving gene therapy. We did not detect any change in brain activity after gene therapy when the 9 patients were analysed as a group. However, on an individual basis, one patient self-reported a change in colour perception, corroborated by improved performance on a psychophysical task designed to selectively identify cone function. This suggests a level of cone sensitivity that was lacking pre-treatment, further supported by a subtle but reliable change in cortical activity within their primary visual cortex.

Investigation through Animal-Computer Interaction: A Proof-of-Concept Study for the Behavioural Experimentation of Colour Vision in Zoo-Housed Primates.

Zoos are an important repository of animals, which have a wide range of visual systems, providing excellent opportunities to investigate many comparative questions in sensory ecology. However, behavioural testing must be carried out in an animal welfare-friendly manner, which is practical for zoo staff. Here, we present a proof-of-concept study to facilitate behavioural research on the sensory ecology of captive primates. A system consisting of a tablet computer and an automated feeder connected wirelessly was developed and presented to captive primate species to evaluate interactions with and without previous training. A colour stimulus, analogous to the Ishihara test, was used to check the level of interaction with the device, supporting future studies on sensory ecology with zoo animals. Animals were able to use the system successfully and displayed signs of learning to discriminate between the visual stimuli presented. We identified no risk for small primates in their interactions with the experimental setup without the presence of keepers. The use of electronic devices should be approached with caution to prevent accidents, as a standard practice for environmental enrichment for larger animals (e.g., spider monkeys). In the long term, the system developed here will allow us to address complex comparative questions about the functions of different visual systems in captive animals (i.e., dichromatic, trichromatic, etc.).

The modelling of flower colour: spectral purity or colour contrast as biologically relevant descriptors of flower colour signals for bees depending upon the perceptual task.

Flower colour is an important mediator of plant-pollinator interactions. While the reflectance of light from the flower surface and background are governed by physical properties, the perceptual interpretation of such information is generated by complex multilayered visual processing. Should quantitative modelling of flower signals strive for repeatable consistency enabled by parameter simplification, or should modelling reflect the dynamic way in which bees are known to process signals? We discuss why colour is an interpretation of spectral information by the brain of an animal. Different species, or individuals within a species, may respond differently to colour signals depending on sensory apparatus and/or individual experience. Humans and bees have different spectral ranges, but colour theory is strongly rooted in human colour perception and many principles of colour vision appear to be common. We discuss bee colour perception based on physiological, neuroanatomical and behavioural evidence to provide a pathway for modelling flower colours. We examine whether flower petals and floral guides as viewed against spectrally different backgrounds should be considered as a simple colour contrast problem or require a more dynamic consideration of how bees make perceptual decisions. We discuss that plants such as deceptive orchids may present signals to exploit bee perception, whilst many plants do provide honest signalling where perceived saturation indicates the probability of collecting nutritional rewards towards the centre of a flower that then facilitates effective pollination.

Test time affects Farnsworth D15 outcomes in practiced, but not unpracticed, subjects with color vision deficiency.

Imposing a time limit on the Farnsworth D15 test may prevent patients from compromising the test. This study aimed to investigate the effect of test time on the Farnsworth D15 color vision test in unpracticed and practiced subjects and determine an optimal test time. Twenty-one subjects (mean/standard deviation age, 33.1/9.3 years) with a range of congenital color vision deficiency participated in the study. Pseudoisochromatic plate screening, Farnsworth D15, and anomaloscope testing were performed for classification purposes. At each of 2 visits, 10 trials of the Farnsworth D15 were performed with a range in test times from 30 seconds to 10 minutes. Between visits, subjects practiced the test. Major crossovers were used as the outcome measure. A repeated-measures analysis of variance compared the scores across trials. Post hoc Dunnett's testing analyzed the pairwise data. Although no significant difference in the mean number of major crossovers was found across the 10 trials for the first visit ( F (9, 180) = 1.30, p=0.24), a significant difference was found for the second visit ( F (9, 180) = 4.77, p<0.001). The range of mean number of major crossovers for the second visit was 1.71 to 5.1, with the 30-second trial resulting in the largest number of major crossovers and the longest trial resulting in the smallest number of major crossovers. Analysis showed that a 2-minute time limit resulted in a Farnsworth D15 outcome that would be expected based on the anomaloscope for a majority of subjects. In this study, test time was found to affect performance in practiced subjects but not in unpracticed subjects. Based on this study, we recommend enforcing a time limit of 2 minutes to discourage those who try to pass the Farnsworth D15 through practice. Additional measures, such as recording patient behavior, can also be taken.

Ophthalmic Findings in the KIF1A-Associated Neurologic Disorder (KAND)

PurposeTo define the ophthalmic manifestations in KIF1A-associated neurological disorder (KAND), a rare, progressive neurodegenerative disorder caused by pathogenic variants in the KIFA1 gene. DesignCross-sectional study. MethodsClinical ophthalmic examination and multimodal imaging were performed for 24 participants enrolled in the KIF1AOutcome measures, Assessments, Longitudinal And endpoints (KOALA) Study. Visual evoked potentials (VEP) were performed on select participants. ResultsThe average central visual acuity in pediatric participants was 20/43 (logMAR 0.329, range 0.0-1.0), and 20/119 (logMAR 0.773, range 0.471-1.351) in adults. Ninety-five percent of participants examined had some degree of optic nerve atrophy detected by clinical examination and/or optical coherence tomography (OCT). Almost forty percent had strabismus. Color vision, visual fields and stereopsis were impaired in most participants who were able to participate in testing. VEP showed varying degrees of signal slowing and diffuseness. ConclusionsOptic nerve atrophy is the primary ocular finding in individuals with KAND and is present at higher prevalence than previously reported. The degree of the atrophy is likely dependent on the severity of the pathogenic variant and possibly the age of the patient. Adults had worse vision on average than children, suggesting possible decline in vision with age. Strabismus in this cohort was common. Visual evoked potentials showed findings consistent with optic neuropathy and visual dysfunction even in the absence of obvious structural changes on OCT. Families should be counseled regarding visual impairment in KAND patients, so as to obtain appropriate support and assistance to maximize safety, functionality, and learning.

Toward Full‐Color Vision Restoration: Conjugated Polymers as Key Functional Materials in Artificial Retinal Prosthetics

AbstractFor the prosthetic retina, a device replacing dysfunctional cones and rods, with the ability to mimic the spectral response properties of these photoreceptors and provide electrical stimulation signals to activate residual visual pathways, can relay sufficient data to the brain for interpretation as color vision. Organic semiconductors including conjugated polymers with four different bandgaps providing wavelength‐specific electrical responses are ideal candidates for potential full‐color vision restoration. Here, conjugated polymer photocapacitor devices immersed in electrolyte are demonstrated to elicit a photovoltage measured by a Ag/AgCl electrode 100 microns from the device of ≈−40 mV for 15–39 µW mm−2 of incident light power density at three wavelengths: 405 nm for blue photoreceptor candidate material, 534 nm for green, 634 nm for red. Photoresponse is substantially improved by introducing polymer donor/acceptor molecules bulk heterojunctions. Devices with bulk heterojunction configurations achieved at least −70 mV for green candidates with the highest at −200 mV for red cone candidates. These findings highlight the potential for organic materials to bridge the gap toward natural vision restoration for retinal dystrophic conditions such as age‐related macular degeneration, Stargardt disease, or retinitis pigmentosa and contribute to the ongoing advancements in visual prosthetic devices.

Accessibility of United States ophthalmology hospital webpages to people with visual disabilities

PurposeEnhancing the accessibility of ophthalmology webpages can help individuals with vision access needs obtain essential appointment information, educational resources, and available ophthalmic services. This study evaluated the accessibility of these webpages for patients with visual impairment and color vision deficiencies. DesignRetrospective cross-sectional study. MethodsIn February 2024, the Web Content Accessibility Guidelines 2.0 (WCAG 2.0) were used to assess the accessibility of the web homepages of the top-ranked ophthalmology institutes in the United States using three evaluation tools: AChecker, ARC Toolkit, and WAVE. The webpages of the 38 top-ranked hospitals for ophthalmology in the 2023 US News & World Report were evaluated. ResultsAll assessed ophthalmology hospital and institute webpages had accessibility issues. The issues identified by each tool significantly impeded webpage navigation, with the mean number of issues as follows: AChecker (13.08, SD = 14.51), ARC Toolkit (16.21, SD = 17.68), and WAVE (6.47, SD = 7.14). The mean number of color contrast issues per website was 10.18 (SD = 15.84), present in 87 % (33/38) of the websites assessed. Most issues made information and interface components difficult to perceive (297/497, 59.76 %), and websites difficult to navigate or operate (145/497, 29.18 %). Common issues affecting people who are blind or have low vision and rely on screen readers included the absence of alternative text for images, hyperlinks without destination information, and missing instructions for user data input (e.g., search bars). ConclusionsOphthalmology webpages should be revised to comply with WCAG guidelines to improve accessibility for people with vision access needs. Addressing these issues can reduce information inequities for patients with visual disabilities and enhance their understanding of clinical processes, treatment, care plans, and available services such as transportation and online support groups.

Triad of benign fleck retina with keratoconus with myopia – A rare case report

A 24-year-old male presented with a complaint of frequent change of glasses in both eyes. His best corrected visual acuity was 20/20 OD and 20/30 OS with a correction of − 6 DS/−3.75 DC @ 50° and − 4.5 DS/−3.25 DC @140°, respectively. Anterior-segment examination revealed a thin steep cornea with normal intraocular pressure in both eyes. Dilated fundus examination showed multiple yellow-white flecked lesions involving the entire fundus but sparing the fovea with pigmented lattices in both eyes. The flecks appeared as localized elevation at the RPE-Bruch’s membrane complex on optical coherence tomography. Corneal topography was suggestive of keratoconus. Examination of his family members did not reveal any abnormalities. Electroretinogram (ERG), electrooculogram, and color vision testing in both eyes were normal. The diagnosis of benign fleck retina with myopia with keratoconus was made. ERG helps distinguish benign familial fleck retina from other flecked retina syndromes to educate the patient about their visual prognosis. To the best of our knowledge, no such case has been reported in Indian literature till now.

A Comprehensive Cross-sectional Analysis of Prevalence of Congenital Color Vision Deficiency among Patients

A Comprehensive Cross-sectional Analysis of Prevalence of Congenital Color Vision Deficiency among Patients

EVALUATION OF EFFICACY OF COLOUR CORRECTED LIGHT SOURCE IN DETERMINING THE ACCURACY OF SHADE MATCHING DONE WITH A COMMONLY USED SHADE GUIDE SYSTEM BY CONVENTIONAL VISUAL METHOD AND AN INTRA ORAL SPECTROPHOTOMETER

Aim: The objective of this study was to evaluate the efficiency of colour corrected light source in shade matching and to determine accuracies and inter-rater agreement of three shade matching methods (conventional visual method, visual method using colour corrected light source and spectrophotometric method). Methodology: In the conventional visual method and the visual method using colour corrected light source, four examiners with normal colour vision matched five target control shade tabs taken from the VITAPAN 3D MasterTM shade guide, with other full set of the same shade guide. Shade matching with the colour corrected light source was done under daylight mode simulating 5500K or natural daylight. Each tab was matched three times to determine repeatability of visual examiners. In the spectrophotometric method, two independent examiners matched the control tabs with three repetitions for each tab. The data was collected and statistical analysis was performed. Results: Visual method using colour corrected light source produced more accurate results (80%) than the conventional visual method (68.3%) and spectrophotometric method (0%), thus proving the efficacy of colour corrected light source (p&lt;0.05). All three methods exhibited poor inter-rater agreement. Conclusion: The question is whether handheld light correcting devices and digital assessments are clinically useful or are they unreliable andunnecessary costly. Even though visual shade matching is subjective, it is not inferior and should not be underrated. The low accuracy value obtained for the spectrophotometer may be a misrepresentation of the machines capabilities due to its inability to measure any reading asclose to the correct value. If both analyses are combined, digital determination of the basic shade and visual determination of the effects, can provide the best possible esthetic outcome. Although human eye will be the finalarbitrator, success can best be achieved by combining traditional artistic techniques with advancements in technology, complemented with innovations in colour-related research, education, and training of dental professionals.

Prevalence and Causes of Visual Impairment and Blindness Among Students of Blind Schools of Bihar, India

Aim: Visual impairment and blindness are serious public health issues, especially in developing countories, like India. Data on causes of childhood visual impairment and blindness in Bihar are limited. The aim of this study was to determine the leading causes of visual impairment and blindness in blind schools of Bihar Study design: A cross sectional study was done in seven blind schools of Bihar Methods: Seven blind schools were visited after taking permission from principal. Written informed consent from parents was taken. Detailed ocular and systemic examination was done for all 218 students. Comprehensive eye examinations were performed, including distance visual acuity, anterior and posterior segment examinations, refraction, color vision, and visual field testing. Anatomical and etiological categorization of causes of visual impairment/Blindness was done. Results: A total 218 students were examined. 90.82% of students were blind and 9.17% severely visually impaired. Major anatomical causes of visual impairment and blindness were Microphthalmos (24.31%), Anophthalmos (23.39%), Optic Atrophy (9.63%) and Corneal Scar (7.80%). Etiologically the most common cause was of unknown etiology followed by postnatal factors. Preventable or treatable causes, such as glaucoma, cataract, and refractive errors, represented 22.48% of the cases Conclusion: Blindness and Low vision due to congenital ocular conditions affecting whole globe was the most common cause, further population based studies are needed to know the exact magnitude of problem and to make strategies to decrease the incidence. There is a need to strengthen current primary preventions strategies while tertiary referral centers, Low Vision setups, awareness program regarding Low Vision, special education, rehabilitation, ocular disability benefits and many more things need to be set up in the different health zones of the state to manage childhood preventable and avoidable blindness.

Impact of Prolonged Screening and COVID-19 Infection on Acquired Colour Vision Deficiencies Assessed by the Farnsworth–Munsell 100 Hue Test

Over the past decade, global screening time has increased, a trend intensified by the COVID-19 pandemic, leading to the integration of screens into daily life. Studies have documented the adverse effects of prolonged screening on ocular health and binocular vision, such as dry eye syndrome, blurry vision, headaches, myopia, and visual fatigue. However, it remains unclear if prolonged screening affects the development of colour vision defects. Objectives: This study aimed to determine the relationship between (a) prolonged screening and acquired colour vision deficiencies and (b) COVID-19 infection and acquired colour vision deficiencies. Methods: A population of 50 individuals with normal trichromatic vision, aged 20 to 30 years, with an average daily screening time of 516.7 min, was evaluated. Participants were initially screened using the Ishihara 32-plate Test to exclude those with congenital colour vision deficiencies. The Farnsworth–Munsell 100 Hue Test (FM100H) and Square Root Total Error Score (√TES) were used to evaluate acquired colour vision deficiencies under standardized conditions. The dataset underwent dual analysis: (1) detailed statistical scrutiny and (2) comparison of √TES values with historical data from 1982, 1991, 2001, and 2002. Results: The global group had a √TES (Mean ± SD) of 5.40 ± 1.58, the COVID-19 subgroup 5.46 ± 1.62, and the non-COVID-19 subgroup 5.32 ± 1.51. No significant differences were found between the √TES values from this population and those reported in previous studies. Statistical analysis showed no significant correlation between gender and COVID-19 infection with √TES values. Conclusions: Neither screening time nor COVID-19 infection appears to significantly impact the occurrence of permanently acquired colour vision deficiencies in individuals aged 20 to 30 years.

Visual disorders in children with shunted hydrocephalus.

The introduction of shunt operations in neurosurgical practice gave a chance for life to these patients and significantly improved its quality. Along with its positive effect, surgical treatment is associated with a number of complications that, together with hydrocephalus itself, affect the subsequent development of shunted patients in the short and long term. In the long term, problems observed in shunted patients are mental retardation, cerebral palsy (CP), epilepsy, hearing and vision disorders. Visual disturbances are common in children with shunted hydrocephalus. These include reduced visual acuity, eye movement disorders, refractive anomalies, visual field defects, reduced color vision and strabismus, optic atrophy. The mechanism of visual disturbances is associated with damage to the oculomotor pathways, optic nerves and optic radiation, dilatation of the lateral ventricles, and damage to the periventricular white matter. Age at onset of hydrocephalus and ventricular dimension are important in the development of visual disturbances and placement of a shunting system can improve visual function. At the same time ophthalmic disturbances may be the first and only sign of shunt dysfunction and rapid normalization of elevated ICP preserves vision. Visual disturbances in patients with shunted hydrocephalus correlate with higher incidence of CP and epilepsy. They determine the children’s social integration and quality of life.

Evaluation of contrast sensitivity in patients with congenital red-green color vision deficiency.

To evaluate mesopic and photopic contrast sensitivity in patients with congenital red-green color vision deficiency regarding with and without glare conditions and to compare these findings with age- and gender-matched healthy controls with normal color vision. Patients with congenital red-green color vision deficiency and age- and gender-matched healthy controls were included in this cross-sectional comparative study. Contrast sensitivity measurements were taken from all subjects in 4 different conditions; binocular mesopic-without glare, mesopic-with glare, photopic-without glare, photopic-with glare, and the results were compared. Twenty one patients with color vision deficiency (13 deuteranopic, 8 protanopic) and 22 age- and gender-matched healthy controls were included in the study. The mean age was 35.2 ± 13.5years in the protan group, 30.6 ± 7.7years in the deutan group, 32.0 ± 8.8years in the control group, and there was no significant difference in age between the groups (P > 0.05). The mean mesopic and photopic contrast sensitivity values of the groups at all spatial frequencies (1.5, 3, 6, 12, 18cpd) were not statistically significant when evaluated by the multifactor repeated measures test of ANOVA to evaluate the effect of light conditions (with and without glare) (P > .05). Mesopic and photopic contrast sensitivity values of patients with congenital red-green color vision deficiency were similar to healthy controls regarding with and without glare conditions.

Visual evoked potentials in patients with congenital color vision deficiency.

Congenital color vision deficiency (CCVD) is an eye disease characterized by abnormalities in the cone cells in the photoreceptor layer. Visual evoked potentials (VEPs) are electrophysiological tests that physiologically examine the optic nerve, other visual pathways, and the visual cortex. The aim of this research was to determine whether there are VEP abnormalities in CCVD patients. Patients with CCVD and healthy individuals were included in this prospective case-control study. Participants with eye disease or neurodegenerative disease were excluded from the study. Pattern reversal VEP (PVEP), flash VEP (FVEP), and optical coherence tomography were performed on all participants. Twenty healthy individuals (15 male) and 21 patients with CCVD (18 male) were included in the study. The mean ages of healthy individuals and patients with CCVD were 29.8 ± 9.6 and 31.1 ± 10.9years (p = 0.804). Retinal nerve fiber layer thickness and central macular thickness values did not differ between the two groups. In PVEP, Right P100, Left N75, P100, N135 values were delayed in CCVD patients compared to healthy individuals (p = 0.001, p = 0.032, p = 0.003, p = 0.032). At least one PVEP and FVEP abnormality was present in nine (42.9%) and six (28.6%) of the patients, respectively. PVEP or FVEP abnormalities were found in 13 (61.9%) of the patients. This study indicated that there may be PVEP and FVEP abnormalities in patients with CCVD.

Effect of Blue Light Filter Intraocular Lens (IOL) on Colour Vision.

Purpose The objective of this study is to knowthe effect of blue light filter (BF) intraocular lenses (IOL) on colour vision of Sudanese patiens as BF IOLs are relatively new in Sudan and its effect on Sudanese patients is not yet studied. Methods This was a descriptive cross-sectional observational study. Data collection was done through interview andpretested structured questionnaire containing three sections: (i) personal data, (ii) past medical and ocular surgical history, and (iii) visual acuity (VA), the anterior and posterior segment exam result, and the D15photopic color vision test result. Results In this study, 206 eyes of 103 patients were enrolled. Of them, 57 (55.3%) were females and 46 (44.7 %) were males. The mean age of the participants was 58.38 years±11.488 (SD). Furthermore, 81 patients (78.64%) achieved normal D15 color vision test results, while 22 patients (21.4%) had abnormal results. There was a significant effect (P=.00) on photopic color vision perception. Finally, the gender-wise performance showed an insignificant difference (P=.933)with 78.3% of the males having normal D15 color vision test and the females having slightly better results with 78.9 %. Conclusions The results suggested that implantation of BF IOLs has a significanteffect on photopic color vision perception.

Assessing the Impact of Simulated Color Vision Deficiency on Ophthalmologists' Ability to Differentiate between Choroidal Melanoma and Choroidal Nevus.

Background: Color vision deficiency (CVD) is an often-overlooked issue within the medical community, and its consequences remain insufficiently explored. We aim to evaluate how CVD affects diagnostic accuracy and distinguish between malignant choroidal melanoma and benign choroidal nevus among ophthalmologists. Methods: In this cross-sectional study, we engaged ophthalmologists through a web-based survey distributed via the professional ophthalmology society's social media channels. The survey encompassed a series of three fundus images representing normal fundus, choroidal nevus, and choroidal melanoma. Each image underwent simulation for the three primary types of CVD-protanopia, deuteranopia, and tritanopia-alongside a non-simulated version. Results: The study included 41 participants, averaging 40 years of age (±9.2), comprising 28 (68%) men and 13 (32%) women. Significantly lower rates of identifying orange pigments were observed in simulated protanopia images compared to non-simulated ones (p = 0.038). In simulated deutranopia images, the recognition of melanotic lesions was notably reduced compared to non-simulated images (p = 0.048). No such limitation was observed for tritanopia. However, participants retained their ability to identify subretinal fluid and estimate tumor thickness in simulated and non-simulated images. Concerning simulated images of choroidal nevi, participants misdiagnosed nevi as choroidal melanoma in 37% of cases in simulated protanopia nevi images and 41% in simulated deutranopia nevi images. This resulted in unnecessary referrals of benign lesions as malignant, emphasizing the potential for mistaken diagnoses. Nevertheless, almost all simulated images of malignant melanoma were correctly referred for specialized oncological treatment. Conclusions: The simulated CVD conditions of protanopia and deuteranopia affected the accuracy of identifying the melanotic nature of the choroidal tumor and the presence of orange pigments. This limitation led to challenges in correctly diagnosing choroidal melanoma and choroidal nevus, resulting in extra referrals for nevus cases. However, participants were safe and could still determine the possible risk of eyes with choroidal melanoma, so most referred melanoma cases to specialized oncologists as needed.

The mechanism of human color vision and potential implanted devices for artificial color vision.

Vision plays a major role in perceiving external stimuli and information in our daily lives. The neural mechanism of color vision is complicated, involving the co-ordinated functions of a variety of cells, such as retinal cells and lateral geniculate nucleus cells, as well as multiple levels of the visual cortex. In this work, we reviewed the history of experimental and theoretical studies on this issue, from the fundamental functions of the individual cells of the visual system to the coding in the transmission of neural signals and sophisticated brain processes at different levels. We discuss various hypotheses, models, and theories related to the color vision mechanism and present some suggestions for developing novel implanted devices that may help restore color vision in visually impaired people or introduce artificial color vision to those who need it.