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Purpose: This cross-sectional study aimed to estimate the prevalence and distribution of color vision deficiency (CVD) among school children aged 6–16 in the Moradabad district of Uttar Pradesh, India. Methods: Between November 1, 2022, and March 31, 2023, a multidisciplinary team conducted school-based eye screening camps, screening 1329 students from four schools. The screening included visual acuity measurement, refraction, ocular alignment evaluation, and Ishihara’s plate test for CVD. Results: Ocular examinations conducted on 1329 students from four schools unveiled a range of ocular conditions. These included bilateral moderate ptosis in 0.1%, nystagmus in 0.1%, hypermetropia in 0.6%, myopia in 7.0%, astigmatism in 2.8%, and pseudophakic in 0.1% of students. The study identified CVD in 2.4% of participants (2.8% of males and 2.2% of females). Further breakdown revealed a 2.4% prevalence on the right and 1.5% on the left, with red and green color vision deficiencies observed. Notably, primary education, middle education, and secondary education levels showed CVD prevalence of 0.4%, 0.97%, and 0.97%, respectively. Conclusion: The study contributes valuable insights into ocular morbidities, emphasizing the prevalence of CVD among school children in the Moradabad district. The findings underscore the need for tailored interventions, early screening, and awareness campaigns to address the specific needs of affected children in diverse geographical and educational settings.

In this study, multifunctional Fresnel lenses were explored as a potential solution for correcting vision in patients with color vision deficiency (CVD) and high myopia. Current studies have primarily focused on color vision correction through the 3D printing of glasses and contact lenses. However, the potential of 3D-printed multifunctional devices, such as Fresnel lenses, goes beyond addressing a single vision correction issue. For this study, computer-aided design (CAD) model of Fresnel lens with high diopter based on constant height configuration was developed. The CAD model was successfully fabricated using vat photopolymerization 3D printer, employing laboratory-prepared transparent HEMA resin. The resin was modified with two Atto dyes (565 nm and 488 nm), known for their ability to filter out problematic wavelengths (400–500 nm and 540–580 nm) to address color vision deficiency. The printed lenses were characterized by their chemical, physical, and optical properties using various characterization techniques. The focusing performance was evaluated using focal length measurements, and the results obtained were less than 2 mm deviation from the design value, having the potential to assist in higher myopic vision correction. The resulting optical spectra were compared with commercial glasses, revealing close agreement for CVD correction. These results expand the potential applications of multifunctional Fresnel lenses in ophthalmology, demonstrating their effectiveness as vision-correcting lenses and imaging systems.

To help maximize the impact of scientific journal articles, authors must ensure that article figures are accessible to people with color-vision deficiencies (CVDs), which affect up to 8% of males and 0.5% of females. We evaluated images published in biology- and medicine-oriented research articles between 2012 and 2022. Most included at least one color contrast that could be problematic for people with deuteranopia (‘deuteranopes’), the most common form of CVD. However, spatial distances and within-image labels frequently mitigated potential problems. Initially, we reviewed 4964 images from eLife, comparing each against a simulated version that approximated how it might appear to deuteranopes. We identified 636 (12.8%) images that we determined would be difficult for deuteranopes to interpret. Our findings suggest that the frequency of this problem has decreased over time and that articles from cell-oriented disciplines were most often problematic. We used machine learning to automate the identification of problematic images. For a hold-out test set from eLife (n=879), a convolutional neural network classified the images with an area under the precision-recall curve of 0.75. The same network classified images from PubMed Central (n=1191) with an area under the precision-recall curve of 0.39. We created a Web application (https://bioapps.byu.edu/colorblind_image_tester); users can upload images, view simulated versions, and obtain predictions. Our findings shed new light on the frequency and nature of scientific images that may be problematic for deuteranopes and motivate additional efforts to increase accessibility.

Purpose: This study was conducted to determine the prevalence of color vision deficiency (CVD) and create awareness about the burden of CVD among drivers. Methodology: This was a retrospective cross-sectional study of 3486 participants (men, n = 2789) who applied for/renewed their drivers’ licenses in Al Ain City, Abu Dhabi, United Arab Emirates (UAE). All drivers had their visual acuity (VA) and color vision measured using standard procedures and the data was analyzed using descriptive statistics. Results: The overall prevalence of CVD was 3.13% (95% CI: 2.59–3.75). No participants had visual impairment (best-corrected distance VA worse than 6/18) and no female driver had CVD. The prevalence of CVD among the male drivers was 3.91% (95% CI: 3.25–4.69), and more among the younger drivers (18–29 years). Conclusion: Although the prevalence of CVD was low, to ensure inclusivity and the safety of all road users in the UAE, it is recommended that traffic lights and road signs that mainly use connotative color coding be adapted to include denotative clues which can be interpreted by drivers with CVD. A prospective study in all approved eye testing centers for drivers should be conducted to obtain representative CVD data of drivers in the UAE.

Objective: To Assess and compare different types of color blindness in primary school children also to appraise the self-awareness levels regarding this ailment amongst them. Study Design: Cross Sectional study. Setting: Different Primary Schools of Karachi in Collaboration with Department of Physiology, Jinnah Medical and Dental College Karachi. Period: 1st October 2020 to 1st December 2020. Methods: 146 primary school children of both genders aged between 5 to 12 years were assessed by prescribed questionnaire and Ishahara Chart for color blindness. Result: Out of the 148 students who underwent screening, only 16 were diagnosed with color blindness, indicating a prevalence of 10.8% among primary school children in Karachi. Of these 16 students, males exhibited a higher incidence of color blindness (56.25%) than females (47.35%). Conclusion: The incidence of color blindness is higher in males than females with significant association with family history and night blindness. Colour blindness unawareness also significantly found in this study. It is recommended to have an eye checkup at the start of school and to have regular eye examination to avoid any hindrances and get the right help. [ABSTRACT FROM AUTHOR]

Long-and middle-wavelength cone photoreceptors, which are responsible for our visual acuity and color vision, comprise -95% of our total cone population and are concentrated in the fovea of our retina. Previously, we characterized the disease mechanisms of the L/M-cone opsin missense mutations N94K, W177R, P307L, R330Q and G338E, all of which are associated with congenital blue cone monochromacy (BCM) or color-vision deficiency. Here, we used a similar viral vector-based gene delivery approach in M-opsin knockout mice to investigate the pathogenic consequences of the BCM or color-vision deficient associated L-cone opsin (OPN1LW) mutants K82E, P187S, and M273K. We investigated their subcellular localization, the pathogenic effects on cone structure, function, and cone viability. K82E mutants were detected predominately in cone outer segments, and its expression partially restored expression and correct localization of cone PDE6α' and cone transducin γ. As a result, K82E also demonstrated the ability to mediate cone light responses. In contrast, expression of P187S was minimally detected by either western blot or by immunohistochemistry, probably due to efficient degradation of the mutant protein. M273K cone opsin appeared to be misfolded as it was primarily localized to the cone inner segment and endoplasmic reticulum. Additionally, M273K did not restore the expression of cone PDE6α' and cone transducin γ in dorsal cone OS, presumably by its inability to bind 11-cis retinal. Consistent with the observed expression pattern, P187S and M273K cone opsin mutants were unable to mediate light responses. Moreover, expression of K82E, P187S, and M273K mutants reduced cone viability. Due to the distinct expression patterns and phenotypic differences of these mutants observed in vivo, we suggest that the pathobiological mechanisms of these mutants are distinct. [ABSTRACT FROM AUTHOR]

Although color vision deficiencies are very prevalent, there are no ideal methods for assessing color vision in all environments. We compared a new digital and automated method that quantifies color perception for the three protan, deutan, and tritan axes with two of the most commonly used color tests in daily practice: the Ishihara 38 plates test and the Farnsworth–Munsell 100-Hue test. One hundred patients underwent a triple examination composed of the new DIVE Color Test, the Ishihara test, and the Farnsworth–Munsell 100-Hue test. The DIVE Color Test was performed twice in forty participants to assess its repeatability. In the trichromatic group, the mean age stood at 20.57 ± 9.22 years compared with 25.99 ± 15.86 years in the dyschromatic group. The DIVE and Ishihara tests exhibited excellent agreement in identifying participants with color deficiency (Cohen's kappa = 1.00), while it was 0.81 when comparing DIVE and Farnsworth. The correlation between the global perception values of Farnsworth (TES) and DIVE (GCS) was 0.80. The repeatability of the DIVE Color Test was high according to Bland–Altman analysis with an intraclass correlation coefficient of 0.83. According to Ishihara, the DIVE Color Test proved to be an effective and reproducible tool for red–green color vision deficiency detection, capable of determining the severity of the defect in each of the three axes faster and more accurately than both Ishihara and Farnsworth. [ABSTRACT FROM AUTHOR]

Long-and middle-wavelength cone photoreceptors, which are responsible for our visual acuity and color vision, comprise ~95% of our total cone population and are concentrated in the fovea of our retina. Previously, we characterized the disease mechanisms of the L/M-cone opsin missense mutations N94K, W177R, P307L, R330Q and G338E, all of which are associated with congenital blue cone monochromacy (BCM) or color-vision deficiency. Here, we used a similar viral vector-based gene delivery approach in M-opsin knockout mice to investigate the pathogenic consequences of the BCM or color-vision deficient associated L-cone opsin (OPN1LW) mutants K82E, P187S, and M273K. We investigated their subcellular localization, the pathogenic effects on cone structure, function, and cone viability. K82E mutants were detected predominately in cone outer segments, and its expression partially restored expression and correct localization of cone PDE6α’ and cone transducin γ. As a result, K82E also demonstrated the ability to mediate cone light responses. In contrast, expression of P187S was minimally detected by either western blot or by immunohistochemistry, probably due to efficient degradation of the mutant protein. M273K cone opsin appeared to be misfolded as it was primarily localized to the cone inner segment and endoplasmic reticulum. Additionally, M273K did not restore the expression of cone PDE6α’ and cone transducin γ in dorsal cone OS, presumably by its inability to bind 11-cis retinal. Consistent with the observed expression pattern, P187S and M273K cone opsin mutants were unable to mediate light responses. Moreover, expression of K82E, P187S, and M273K mutants reduced cone viability. Due to the distinct expression patterns and phenotypic differences of these mutants observed in vivo, we suggest that the pathobiological mechanisms of these mutants are distinct.

AIM: To investigate the prevalence of color vision deficiency (CVD) among college students and their quality of life (QoL) in a Chinese college. METHODS: This cross-sectional study was performed in Sichuan University in Chengdu, China. The questionnaire containing participants' demographic data, as well as CVD related QoL was distributed to students who were screened as CVD [by Color Vision Examination Plates (Version 6)] in 2022 freshman entrance examination. Color blindness QoL (CBQoL) and utility analysis were used to evaluate the QoL of CVD students. RESULTS: There were 381 of 17 303 (2.20%) students screened as CVD, including 368 (4.11%) males and 13 (0.16%) females. A total of 317 students completed the questionnaire, the response rate was 83.20%. Only 166 participants (52.3%) knew they have CVD before the physical examination for college entrance examination, while a total of 145 participants (45.74%) hoped to be diagnosed earlier. The medians of CBQoL score and utility were 5.85 (range 2.2-6) and 1 (range 0-1), respectively. The proportions of students whose QoL is affected by CVD were 67.63% (211/312) and 42.27% (134/317) measured by CBQoL and utility analysis respectively. CONCLUSION: The prevalence of CVD in males is much higher than that in females. The time when CVD students first became aware of their CVD is relatively late. The QoL of the study population is quite high, while a large proportion of students' QoL are affected by CVD. It is suggested that as a congenital defect, CVD screening in China should be earlier, and appropriate guidance and support are needed for CVD patients to help them better adapt to life, study, and work.

Although color vision deficiencies are very prevalent, there are no ideal methods for assessing color vision in all environments. We compared a new digital and automated method that quantifies color perception for the three protan, deutan, and tritan axes with two of the most commonly used color tests in daily practice: the Ishihara 38 plates test and the Farnsworth–Munsell 100-Hue test. One hundred patients underwent a triple examination composed of the new DIVE Color Test, the Ishihara test, and the Farnsworth–Munsell 100-Hue test. The DIVE Color Test was performed twice in forty participants to assess its repeatability. In the trichromatic group, the mean age stood at 20.57 ± 9.22 years compared with 25.99 ± 15.86 years in the dyschromatic group. The DIVE and Ishihara tests exhibited excellent agreement in identifying participants with color deficiency (Cohen’s kappa = 1.00), while it was 0.81 when comparing DIVE and Farnsworth. The correlation between the global perception values of Farnsworth (TES) and DIVE (GCS) was 0.80. The repeatability of the DIVE Color Test was high according to Bland–Altman analysis with an intraclass correlation coefficient of 0.83. According to Ishihara, the DIVE Color Test proved to be an effective and reproducible tool for red–green color vision deficiency detection, capable of determining the severity of the defect in each of the three axes faster and more accurately than both Ishihara and Farnsworth.

Every day, billions of people around the world use public transport. However, it does not always run smoothly for everyone. People with special needs, such as those with disabilities, mothers with children, carers with the elderly, or people traveling with large hand luggage, may not be able to keep up with information related to changing to another means of transport within integrated transfer hubs (ITH) due to their limitations. With unlimited access to the internet, internet applications may help solve transfer problems in ITHs. Although there are many online applications to improve public transport, they are not always user-friendly for people with special needs. One solution that focuses precisely on these needs is the prototype of an internet application implemented as part of the research project of the National Center for Research and Development entitled "Transfer without Barriers." As part of this work, a uniform method for validating web applications for use by people with special needs was developed. The usability of the method was tested on a web application supporting the movement of people with special needs around the ITH at Warsaw-Modlin Airport. [ABSTRACT FROM AUTHOR]

Being a Color blindness or color vision deficiency (CVD) is a type of ocular disorder that prevents the recognizing the special colors. Until now, the certain cure for CVD has not been discovered. Recently, glasses and contact lenses based on chemical dyes were investigated as promising tools for color vision deficiency management. In this work, we proposed the plasmonic PDMS-based lenses to improve the red-green color vision deficiency. We utilized polydimethylsiloxane (PDMS) for fabricating the lens which is a biocompatible, nontoxic, stretchable, and transparent material and will be a suitable option for producing the contact lenses. Finally, the suggested contact lens based on PDMS was immersed in a HAuCl4·3H2O gold solution. Our suggested plasmonic lens is based on localized surface plasmon resonance (LSPR) effect and plasmonic gold nanoparticles dispersed in the produced contact lens based on PDMS suggest a suitable color filter for CVD improvement. The fabricated contact lens suggests perfect features including biocompatibility, durability, and stretchability, that will be helpful for color vision deficiency management.

Abstract Color blindness (color vision deficiency) is a disorder that impairs the true perception of colors. Using the information in this study, appropriate policy can be made to identify high-risk groups, as well as educational policies for families to perform more effective genetic diagnosis methods. This study aims to examine the prevalence of color blindness in Iranian students through a meta-analysis. Articles related to color blindness published between January 1990 and December 2020 were searched in Scopus, Cochrane Library, Web of Science (WoS), Science Direct, Embase, SID, MagIran, IranDoc, Medline, and Google Scholar databases. The keywords used were based on medical subject topics (MeSH Terms) and, after careful review, articles were selected according to varied sections of Participants, Exposure, Comparison, and Outcomes (PECO). Participants: students; Exposure: students with color blindness were examined; Comparison: Students from multiple provinces and regions of Iran were surveyed for color blindness; Outcomes: the pooled prevalence of color blindness in Iranian students reported from different provinces. The prevalence of color blindness in Iranian students was 3.8% (95% CI: 2.7–5.4%). The pooled prevalence of color blindness in Iranian male and female students was 4.7% (95% CI: 3.5–6.4%) and 0.7% (95% CI: 0.3–1.3%), respectively. The pooled prevalence of red–green color blindness (Tritan) was 41.7% (95% CI: 18.9–68.8%). The pooled prevalence of red color blindness (Protan) was 13.9% (95% CI: 7.8–23.8%), and the pooled prevalence of green color blindness (Deutan) based on meta-analysis was 45.3% (95% CI: 29–62.7%). Due to the high prevalence of color blindness in students, especially male students, it is necessary to be screened for through genetic tests in couples before having children.

Background: Color vision deficiency (CVD) is an under-reported problem among medical personnel, and its impact is still not well characterized. We aim to assess the impact of CVD among ophthalmologists on the accuracy of diagnosing different benign and malignant choroidal lesions. Methods: This is a cross-sectional study conducted on ophthalmologists. We used a web-based survey to collect responses through professional ophthalmology society social media. The survey included a set of five images for normal fundus, choroidal nevus, circumscribed choroidal hemangioma, choroidal metastasis, and choroidal melanoma, wherein each image simulated the three main types of CVD: protanopia, deuteranopia, and tritanopia, in addition to a non-simulated image. Results: Forty-one participants were included, with a mean age of 40 (±9.2) years. They were 28 (68%) men and 13 (32%) women. Participants showed significantly low accuracy for definite diagnosis for circumscribed choroidal hemangioma, nevus, melanoma, and metastasis when the images simulated protanopia and deuteranopia, but not tritanopia. Nevertheless, participants maintained the capability to recognize the nature of the lesions for both simulated and non-simulated images if they were benign or malignant, thereby ensuring immediate referral for specialized care. The exception was with simulated choroidal nevi images, wherein participants incorrectly assigned simulated protanopia and deuteranopia nevi images to malignant lesions. Conclusion: Protanopia and deuteranopia affected the accuracy of diagnosing several choroidal lesions; however, ophthalmologists with those two simulated CVDs were still able to discriminate between benign and malignant tumors. [ABSTRACT FROM AUTHOR]

Abstract Color‐blindness, or more accurately, color vision deficiency (CVD), which is the inability or decreased ability to distinguish different colors, is one of the commonest visual disorders. Patients with schizophrenia usually have multiple types of visual processing impairments, including color vision impairments. Here, we present a case of schizophrenia with congenital CVD. The patient was aware of his color deficiency since elementary school. We assessed his ability to distinguish medicines based on their color, including those that he had been previously prescribed. Although he could distinguish all of the tablets, he could not distinguish the color of the blister packs, specifically that of the bromazepam 2 mg pack (green) from the 1 mg pack (red). This case suggests that CVD patients might misunderstand the color of medications, which might lead to medication errors, or poor drug adherence. The color universal design principle should be considered when designing tablets and their blister packs, in order to improve medication adherence.

Background and Aims: There is insufficient evidence to support that using electronic or optical color vision devices improve color perception with current advanced technology. The purpose of this study is to compare and analyze the different color vision devices available for patients with color vision deficiency (CVD) and evaluate whether these devices improved their color perception. Methods: This review included randomized, experimental, comparative studies, as well as narrative reviews, prototype and innovation studies, and translational studies, followed by case‐control and clinical trials with nonsurgical interventions studies, that is, electronic color vision devices, optical devices, and contact lens‐based studies, with standardized inclusion and exclusion criteria. Results: The primary outcome studied was the performance of color vision devices, both objective and subjective. Secondary outcomes included the ease of use and accessibility of color vision devices and technology. The grading of recommendation, assessment, development, and evaluation framework was used to develop a systematic approach for consideration and clinical practice recommendation for CVD devices for color‐deficient populations. We incorporated meta‐analysis reports from a total of n = 16 studies that met the criteria which consisted of case‐control studies, prototype and innovation studies, comparative studies, pre‐ and post‐clinical trial studies, case studies, and narrative reviews. Proportion and standard errors, as well as correlations, were calculated from the meta‐analysis for various available color vision devices. Conclusion: This review concludes that commercially available color vision devices, such as EnChroma Glasses, Chromagen filters, and EnChroma Cx‐14 do not provide clinically significant evidence that subjective color perception has improved. As a result, recommending these color vision devices to the CVD population may not prove high beneficial/be counterproductive. However, only a few color shades can be perceived differently. This systematic review and analysis will aid future research and development in color vision devices. [ABSTRACT FROM AUTHOR]

In this study, multifunctional Fresnel lenses were explored as a potential solution for correcting vision in patients with color vision deficiency (CVD) and high myopia. Current studies have primarily focused on color vision correction through the 3D printing of glasses and contact lenses. However, the potential of 3D-printed multifunctional devices, such as Fresnel lenses, goes beyond addressing a single vision correction issue. For this study, computer-aided design (CAD) model of Fresnel lens with high diopter based on constant height configuration was developed. The CAD model was successfully fabricated using vat photopolymerization 3D printer, employing laboratory-prepared transparent HEMA resin. The resin was modified with two Atto dyes (565 nm and 488 nm), known for their ability to filter out problematic wavelengths (400-500 nm and 540-580 nm) to address color vision deficiency. The printed lenses were characterized by their chemical, physical, and optical properties using various characterization techniques. The focusing performance was evaluated using focal length measurements, and the results obtained were less than 2 mm deviation from the design value, having the potential to assist in higher myopic vision correction. The resulting optical spectra were compared with commercial glasses, revealing close agreement for CVD correction. These results expand the potential applications of multifunctional Fresnel lenses in ophthalmology, demonstrating their effectiveness as vision-correcting lenses and imaging systems., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ali, Hisham, Abu Al-Rub and Butt.)

Color vision assessment is essential in clinical practice, yet different tests exhibit distinct strengths and limitations. Here we apply a psychophysical paradigm, Angular Indication Measurement (AIM) for color detection and discrimination. AIM is designed to address some of the shortcomings of existing tests, such as prolonged testing time, limited accuracy and sensitivity, and the necessity for clinician oversight. AIM presents adaptively generated charts, each a N×M (here 4×4) grid of stimuli, and participants are instructed to indicate either the orientation of the gap in a cone-isolating Landolt C optotype or the orientation of the edge between two colors in an equiluminant color space. The contrasts or color differences of the stimuli are adaptively selected for each chart based on performance of prior AIM charts. In a group of 23 color-normal and 15 people with color vision deficiency (CVD), we validate AIM color against Hardy-Rand-Rittler (HRR), Farnsworth-Munsell 100 hue test (FM100), and anomaloscope color matching diagnosis and use machine learning techniques to classify the type and severity of CVD. The results show that AIM has classification accuracies comparable to that of the anomaloscope, and while HRR and FM100 are less accurate than AIM and an anomaloscope, HRR is very rapid. We conclude that AIM is a computer-based, self-administered, response-adaptive and rapid tool with high test-retest repeatability that has the potential to be suitable for both clinical and research applications., Competing Interests: Competing interests JS and PJB are founders of PerZeption Inc. JS and PJB are inventors of the AIM (Angular Indication Measurement) method, including AIM-Color detection and discrimination, which is patented (pending), owned by Northeastern University, Boston, USA, and exclusively licensed to PerZeption Inc. JH declares no competing interest.

To help maximize the impact of scientific journal articles, authors must ensure that article figures are accessible to people with color-vision deficiencies (CVDs), which affect up to 8% of males and 0.5% of females. We evaluated images published in biology- and medicine-oriented research articles between 2012 and 2022. Most included at least one color contrast that could be problematic for people with deuteranopia ('deuteranopes'), the most common form of CVD. However, spatial distances and within-image labels frequently mitigated potential problems. Initially, we reviewed 4964 images from eLife , comparing each against a simulated version that approximated how it might appear to deuteranopes. We identified 636 (12.8%) images that we determined would be difficult for deuteranopes to interpret. Our findings suggest that the frequency of this problem has decreased over time and that articles from cell-oriented disciplines were most often problematic. We used machine learning to automate the identification of problematic images. For a hold-out test set from eLife (n=879), a convolutional neural network classified the images with an area under the precision-recall curve of 0.75. The same network classified images from PubMed Central (n=1191) with an area under the precision-recall curve of 0.39. We created a Web application (https://bioapps.byu.edu/colorblind_image_tester); users can upload images, view simulated versions, and obtain predictions. Our findings shed new light on the frequency and nature of scientific images that may be problematic for deuteranopes and motivate additional efforts to increase accessibility., Competing Interests: HS, CW, AO, SP No competing interests declared, (© 2024, Stevens et al.)

Abstract Background and Aims There is insufficient evidence to support that using electronic or optical color vision devices improve color perception with current advanced technology. The purpose of this study is to compare and analyze the different color vision devices available for patients with color vision deficiency (CVD) and evaluate whether these devices improved their color perception. Methods This review included randomized, experimental, comparative studies, as well as narrative reviews, prototype and innovation studies, and translational studies, followed by case‐control and clinical trials with nonsurgical interventions studies, that is, electronic color vision devices, optical devices, and contact lens‐based studies, with standardized inclusion and exclusion criteria. Results The primary outcome studied was the performance of color vision devices, both objective and subjective. Secondary outcomes included the ease of use and accessibility of color vision devices and technology. The grading of recommendation, assessment, development, and evaluation framework was used to develop a systematic approach for consideration and clinical practice recommendation for CVD devices for color‐deficient populations. We incorporated meta‐analysis reports from a total of n = 16 studies that met the criteria which consisted of case‐control studies, prototype and innovation studies, comparative studies, pre‐ and post‐clinical trial studies, case studies, and narrative reviews. Proportion and standard errors, as well as correlations, were calculated from the meta‐analysis for various available color vision devices. Conclusion This review concludes that commercially available color vision devices, such as EnChroma Glasses, Chromagen filters, and EnChroma Cx‐14 do not provide clinically significant evidence that subjective color perception has improved. As a result, recommending these color vision devices to the CVD population may not prove high beneficial/be counterproductive. However, only a few color shades can be perceived differently. This systematic review and analysis will aid future research and development in color vision devices.

To investigate the occurrence, causes, and risk factors of color vision deficiency among Taif, Saudi Arabia secondary school students. A cross-sectional study was carried out on secondary schools, during the period from 1 to 31 June 2022. Secondary school students, of Taif city, Saudi Arabia. Data were collected using a personal interview with the students using a predesigned questionnaire covering the needed items. Students diagnosed with color blindness were 2.0%; of them, persons diagnosed with protan color blindness were 58.3%, while 41.6% had deutan color blindness, and students diagnosed with CVD were 0.4%. On the other hand, 4.2% could not see shades or tones of the same color and the same percent had difficulty distinguishing between colors. Regarding the cause of CVD, our study revealed that 4.2% of the studied population were due to primary causes (hereditary), and the same percent were due to secondary diseases. As regards family history, 1.0% had a mother and/or father affected by the disease, 0.8% had a sibling with the disease, and 96.3% had no family history. It was also found that there is a significant relationship between CVD and family history (p-value =0.008). There was a higher incidence in males than females, there is a significant relationship between gender and CVD (p-value=0.001). Students diagnosed with color blindness were 2.0%; of them, persons diagnosed with protan color blindness were 58.3%, while 41.6% had deutan color blindness, and students diagnosed with CVD were 0.4%. There was a higher incidence in males than females. [ABSTRACT FROM AUTHOR]

Color blindness (color vision deficiency) is a disorder that impairs the true perception of colors. Using the information in this study, appropriate policy can be made to identify high-risk groups, as well as educational policies for families to perform more effective genetic diagnosis methods. This study aims to examine the prevalence of color blindness in Iranian students through a meta-analysis. Articles related to color blindness published between January 1990 and December 2020 were searched in Scopus, Cochrane Library, Web of Science (WoS), Science Direct, Embase, SID, MagIran, IranDoc, Medline, and Google Scholar databases. The keywords used were based on medical subject topics (MeSH Terms) and, after careful review, articles were selected according to varied sections of Participants, Exposure, Comparison, and Outcomes (PECO). Participants: students; Exposure: students with color blindness were examined; Comparison: Students from multiple provinces and regions of Iran were surveyed for color blindness; Outcomes: the pooled prevalence of color blindness in Iranian students reported from different provinces. The prevalence of color blindness in Iranian students was 3.8% (95% CI: 2.7-5.4%). The pooled prevalence of color blindness in Iranian male and female students was 4.7% (95% CI: 3.5-6.4%) and 0.7% (95% CI: 0.3-1.3%), respectively. The pooled prevalence of red-green color blindness (Tritan) was 41.7% (95% CI: 18.9-68.8%). The pooled prevalence of red color blindness (Protan) was 13.9% (95% CI: 7.8-23.8%), and the pooled prevalence of green color blindness (Deutan) based on meta-analysis was 45.3% (95% CI: 29-62.7%). Due to the high prevalence of color blindness in students, especially male students, it is necessary to be screened for through genetic tests in couples before having children. [ABSTRACT FROM AUTHOR]

Background: The Farnsworth-Munsell 100-hue test (FM100-hue) is a color-arrangement test wherein a patient must arrange 85 caps into color order. It is a well-known and widely accepted test, but it is not often used in primary eye care practice because it takes a fairly long time (about 10 minutes) to administer. However, this case report will show the usefulness of the test where other tests of color vision were not able to give a clear picture of a patient's color vision issue. Case Report: A 17-year-old Caucasian female presented with a complaint of having trouble distinguishing different shades of similar colors. The patient had a comprehensive eye exam a week prior to this visit, which did not reveal any significant findings. No family history of color vision deficiency was reported. She passed all color vision screening book tests. Additional tests, including the Farnsworth D15, were passed, but with some anomalies. The FM100-hue test was definitively failed and showed a severe (total error score = 372), non-specific color vision issue with errors in every part of the color circle. The patient was diagnosed as likely having genetically normal color vision, but with very poor hue discrimination. Conclusion: The case shows that the FM100-hue test can identify non-specific color vision issues, even when other color vision tests cannot, and the test has utility in clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study is to investigate the effect of ChromaGen contact lens (CCL) on corneal clarity, expressed through the measurement of corneal densitometry (CD) values. Methods: This study included 22 eyes of 22 patients with congenital red-green color vision deficiency who were admitted to our clinic for the CCL trial. After a detailed ophthalmological examination and CD measurement with Pentacam HR (Oculus Optikgerate GmbH, Wetzlar, Germany), the most appropriate CCLs were defined through pseudoisochromatic plates and inserted for 2 h. The CD measurement was repeated after the removal of the CCL. Comparison was made of CD values before and after the insertion of the most appropriate CCL. The after-CCL/before-CCL ratio was calculated, and the effect of CCL type on this ratio was investigated. Results: The after-CCL values were higher in the anterior, central, posterior, and total thickness of the 0-2 mm concentric zone (p=0.044, p=0.040, p=0.021, and p=0.032, respectively) when compared to the before-CCL values. There was no statistically significant difference between before-CCL and after-CCL values in any layer of the 2-6, 6-10, and 10-12 mm concentric zones (p>0.05, for all). After-CCL/before-CCL ratios were similar in the Magenta2 (M2), Magenta3 (M3), and Violet3 (V3) types of CCLs (p>0.017). Conclusion: Usage for 2 h of CCL was observed to increase CD values in all layers of the 0-2 mm concentric zone irrespective of the type of CCL. Further studies with longer follow-up are required to determine the long-term effects and detect differing effects of CCL with different base curves. [ABSTRACT FROM AUTHOR]

Purpose: Impact of color vision deficiency (CVD) on activities at school and productivity at work and consequential psychosocial difficulties has been reported. Although early detection and awareness help in overcoming these difficulties, screening for CVD is not a part of the school eye-screening initiatives in many countries. This study aimed at reporting the prevalence of CVD among school-going boys in Kanchipuram district, South India. Methods: The study was carried out as part of a school eye-screening program (SES) conducted in Kanchipuram district, Tamil Nadu, India for children between 6 and 17 years. The SES followed a three-phased protocol, which also included screening for CVD for all the boys between 11 and 17 years. The boys underwent CVD screening with Dalton's pseudo isochromatic plates (PIPs) followed by confirmation with Ishihara's PIP. The data were analyzed and the proportion of CVD in boys among different class grades, type of schools, location of schools, blocks of the district, and other clinical characteristics are presented. Results: Totally 250,052 children were screened in 1047 schools of which 74986 (60.61%) were boys between 11 and 17 years (mean age: 13.75 ± 1.91). The overall prevalence of CVD was found to be 2.76% (n = 2073; 95% confidence interval [CI]: 2.65–2.88). CVD was associated with urban locations (3.17% odds ratio [OR]: 1.90 95%CI: 1.69–2.13 P < 0.05) and public schooling (2.87%) (OR: 1.29 95%CI: 1.17–1.43 P < 0.05). Boys with CVD were less likely to have vision impairment (P = 0.002) and myopia (P < 0.001) as compared with boys with normal color vision. There was no significant difference in the proportion of other ocular conditions between children with and without CVD (P > 0.05). Conclusion: The study shows a significant proportion of CVD among boys in Kanchipuram district, India and its association with various demographic and clinical characteristics. Identification of CVD and counseling the stakeholders earlier through school children screening is crucial.

Purpose The aim of this study was to determine the prevalence and types of color vision deficiency (CVD) among primary school students in Alexandria, Egypt. Setting This study was carried out at three primary schools in Alexandria, Egypt. Patients and methods This cross-sectional study was carried out among three primary school students in Alexandria, Egypt. Ocular examination including visual acuity and color vision testing with Ishihara plates (38-plate edition) was performed for all the students included. Further assessment using the Farnsworth–Munsell 100-hue test was performed for students who failed the Ishihara plates test. Results A total of 1000 (495 males and 505 females) school students were screened for CVD. The mean age of the students was 9±2.16 years. The overall prevalence of CVD was 1.9%, with a prevalence of 2.8 and 0.9% in males and females, respectively, a statistically significant difference (P=0.04). Among the CVD students, 36.8% had deuteranopia, 31.5% had deuteranomaly, 26.3% had protanopia, and 5.3% had tritanopia. Conclusion The prevalence of CVD was 1.9%, with a male predominance, among primary school students in Alexandria. Deutan color vision defects were the most prevalent.

The R package colorspace provides a flexible toolbox for selecting individual colors or color palettes, manipulating these colors, and employing them in statistical graphics and data visualizations. In particular, the package provides a broad range of color palettes based on the HCL (hue-chroma-luminance) color space. The three HCL dimensions have been shown to match those of the human visual system very well, thus facilitating intuitive selection of color palettes through trajectories in this space. Using the HCL color model, general strategies for three types of palettes are implemented: (1) Qualitative for coding categorical information, i.e., where no particular ordering of categories is available. (2) Sequential for coding ordered/numeric information, i.e., going from high to low (or vice versa). (3) Diverging for coding ordered/numeric information around a central neutral value, i.e., where colors diverge from neutral to two extremes. To aid selection and application of these palettes, the package also contains scales for use with ggplot2, shiny and tcltk apps for interactive exploration, visualizations of palette properties, accompanying manipulation utilities (like desaturation and lighten/darken), and emulation of color vision deficiencies. The shiny apps are also hosted online at http://hclwizard.org/.

Background: Reverse high-contrast (white-onblack) visual acuity has been shown to improve visual acuity in older patients and patients with pathology under photopic testing. In this study, we investigated whether reverse contrast results in improved visual acuity at mesopic light levels. Methods: Monocular visual acuities (logMAR) were assessed at four different light levels (1 photopic {94 cd/m2} and 3 mesopic {3 cd/m2, 0.75 cd/m2, and 0.38 cd/m2}) in 47 visually normal subjects (27.4±9.3 years). Visual acuity was assessed using an E-ETDRS algorithm, in standard and reverse contrast, at 3 m. Repeated measures ANOVA with post-hoc Tukey testing was used to analyze the data across the light levels. Results: The mean standard contrast visual acuity was -0.07±0.06 under the photopic condition, 0.06±0.08 at 3 cd/m2, 0.17±0.08 at 0.75 cd/m2, and 0.28±0.09 at 0.38 cd/m2. For reverse contrast, it was -0.08±0.06 under the photopic condition, 0.01±0.07 at 3 cd/m2, 0.12±0.08 at 0.75 cd/m2, and 0.22±0.09 at 0.38 cd/m2. There was a significant improvement in visual acuity using reverse contrast under all mesopic light levels (p<0.001), but not under photopic conditions (p=0.15). Conclusions: At mesopic light levels, there were significant differences between standard and reverse contrast. The use of mesopic reverse-contrast visual acuity could be another way to detect subtle changes in visual acuity. Reversecontrast presentations under low lighting conditions may be advantageous for a patient's visual acuity. [ABSTRACT FROM AUTHOR]

In anomalous trichromacy, the color signals available from comparing the activities of the two classes of cone sensitive in the medium and long wavelength parts of the spectrum are much reduced from those available in normal trichromacy, and color discrimination thresholds along the red-green axis are correspondingly elevated. Yet there is evidence that suprathreshold color perception is relatively preserved; this has led to the suggestion that anomalous trichromats post-receptorally amplify their impoverished red-green signals. To test this idea, we measured chromatic discrimination from white and from saturated red and green pedestals. If there is no post-receptoral compensation, the anomalous trichromat's loss of chromatic contrast will apply equally to the pedestal and to the test color. Coupled with a compressively nonlinear neural representation of saturation, this means that a given pedestal contrast will cause a smaller than normal modulation of discrimination sensitivity. We examined cases where chromatic pedestals impair the color discrimination of normal trichromatic observers. As predicted, anomalous observers experienced less impairment than normal trichromats, though they remained less sensitive than normal trichromats. Although the effectiveness of chromatic pedestals in impairing color discrimination was less for anomalous than for normal trichromats, the chromatic pedestals were more effective for anomalous observers than would be expected if the anomalous post-receptoral visual system were the same as in normal trichromacy; the hypothesis of zero compensation can be rejected. This might suggest that the effective contrast of the pedestal is post-receptorally amplified. But on closer analysis, the results do not support candidate simple models involving post-receptoral compensation either. [ABSTRACT FROM AUTHOR]

Objectives: Although color information is important in gastrointestinal endoscopy, there are limited studies on how endoscopic images are viewed by people with color vision deficiency. We aimed to investigate the differences in the visibility of blood vessels during endoscopic submucosal dissection (ESD) among people with different color vision characteristics and to examine the effect of red dichromatic imaging (RDI) on blood vessel visibility., Methods: Seventy-seven pairs of endoscopic images of white light imaging (WLI) and RDI of the same site were obtained during colorectal ESD. The original images were set as type C (WLI-C and RDI-C), a common color vision. These images were computationally converted to simulate images perceived by people with color vision deficiency protanope (Type P) or deutanope (Type D) and denoted as WLI-P and RDI-P or WLI-D and RDI-D. Blood vessels and background submucosa that needed to be identified during ESD were selected in each image, and the color differences between these two objects were measured using the color difference (Δ E 00 ) to assess the visibility of blood vessels., Results: Δ E 00 between a blood vessel and the submucosa was greater under RDI (RDI-C/P/D: 24.05 ± 0.64/22.85 ± 0.66/22.61 ± 0.64) than under WLI (WLI-C/P/D: 22.26 ± 0.60/5.19 ± 0.30/8.62 ± 0.42), regardless of color vision characteristics. This improvement was more pronounced in Type P and Type D and approached Type C in RDI., Conclusions: Color vision characteristics affect the visibility of blood vessels during ESD, and RDI improves blood vessel visibility regardless of color vision characteristics., Competing Interests: Tadakazu Hisamatsu has performed Joint Research with Alfresa Pharma Co. Ltd., EA Pharma Co. Ltd. and received grant support from Mitsubishi Tanabe Pharma Corporation, EA Pharma Co. Ltd., AbbVie GK, JIMRO Co. Ltd., Zeria Pharmaceutical Co. Ltd., Daiichi‐Sankyo, Kyorin Pharmaceutical Co. Ltd., Nippon Kayaku Co. Ltd., Takeda Pharmaceutical Co. Ltd., Pfizer Inc., and Mochida Pharmaceutical Co., Ltd., and consulting and lecture fees from EA Pharma Co. Ltd., AbbVie GK, Janssen Pharmaceutical K.K., Pfizer Inc., Nichi‐Iko Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Kyorin Pharmaceutical Co. Ltd., JIMRO Co., Mochida Pharmaceutical Co., Ltd., Gilead Sciences, Kissei Pharmaceutical Co. Ltd., and Takeda Pharmaceutical Co. Ltd.Jun Miyoshi has received grant support from AbbVie GK, and consulting and lecture fees from EA Pharma Co. Ltd., AbbVie GK, Janssen Pharmaceutical K.K., Jansen Asia Pacific Pte. Ltd., Pfizer Inc., Mitsubishi Tanabe Pharma Corporation, JIMRO Co., Miyarisan Co. Ltd., and Takeda Pharmaceutical Co. Ltd.Akiko Ohno has received lecture fees and borrowed the equipment necessary for image capture during ESD from Olympus Corporation., (© 2024 The Author(s). DEN Open published by John Wiley & Sons Australia, Ltd on behalf of Japan Gastroenterological Endoscopy Society.)

Color‐blindness, or more accurately, color vision deficiency (CVD), which is the inability or decreased ability to distinguish different colors, is one of the commonest visual disorders. Patients with schizophrenia usually have multiple types of visual processing impairments, including color vision impairments. Here, we present a case of schizophrenia with congenital CVD. The patient was aware of his color deficiency since elementary school. We assessed his ability to distinguish medicines based on their color, including those that he had been previously prescribed. Although he could distinguish all of the tablets, he could not distinguish the color of the blister packs, specifically that of the bromazepam 2 mg pack (green) from the 1 mg pack (red). This case suggests that CVD patients might misunderstand the color of medications, which might lead to medication errors, or poor drug adherence. The color universal design principle should be considered when designing tablets and their blister packs, in order to improve medication adherence. [ABSTRACT FROM AUTHOR]

BACKGROUND: Color vision deficiency (CVD) affects approximately one in 12 men and one in 200 women in the world. It is considered a problem in the medical field since the color is often used as a sign in the practice of medicine, in observational assessment, diagnosis, and follow-up. These conditions make the appreciation of color essential in doctors' lives, thus we aimed at finding the prevalence and predictors of CVD in medical students. MATERIALS AND METHODS: This cross-sectional study included 1115 medical students. A pretested questionnaire consisting of personal data, history of vision problems, familial color vision defect, eye surgery, bad trauma on the head or eyes, drugs taken or chemicals exposed to, other health problems, and whether sufficient amount of Vitamin A is taken was used. This was followed by the screening of the participants for CVD using the Ishihara 15-plates test. RESULTS: A total of 1115 students participated in the study; 52.2% were females and the mean age of the participants was 21.7 years (±1.4). The prevalence of definitive CVD was found to be 2.1%; all of which comprised males. Eighty-seven percent of the affected participants were not aware of their color vision problem. A highly statistically significant association was found between history of vision problems and CVD status (P < 0.008). No association were found for nationality, marital status, family history of CVD, history of eye surgery, and eye trauma. CONCLUSION: The percentage of CVD in the present study is lower than that reported by previous studies done in other countries. Many medical students with CVD remain unaware of their condition. Therefore, we recommend early screening of all school-age children, and proper counseling of medical students with definite CVD to take care of their own health and wellbeing. [ABSTRACT FROM AUTHOR]

Background: The Lanthony desaturated color vision test is a color arrangement test wherein a patient must arrange 15 caps into color order. It is a difficult test for color-normal patients and is even more challenging for color vision-deficient patients due to its low saturation, which makes the cap-color differences fairly small. Despite the challenge, this case report will show that the test may not always be reliable. Case Report: A 25-year-old Caucasian male returned to our office for continued evaluation for color vision deficiency. He had previously been diagnosed with protanopia based on anomaloscope testing, which was consistent with other color tests. The patient had previously shown learning on the easier Farnsworth saturated color test and was interested in attempting to learn a harder test. The patient was sent home with a Lanthony color test and Richmond Illuminator. He returned for follow-up testing, which showed that he was able to score perfectly on the Lanthony desaturated color test, which was very surprising. Conclusion: This case shows that for some highly motivated patients, the Lanthony D15 color test may be subverted, and knowledge of this possibility is important for clinicians to consider. [ABSTRACT FROM AUTHOR]

• Propose a fast recolouring algorithm for dichromacy compensation. • The algorithm can compensate contrast loss while preserving the naturalness. • Automatically adapt the balance between contrast enhancement and naturalness preservation to individual images. • Provide two fast solvers for achieving the optimized recolouring results in nearly real time. [Display omitted] People with colour vision deficiency (CVD) may have difficulty recognising or discriminating colours. To enhance their visual details, some methods have been developed to enhance colour contrast. Recently, researchers realized the importance of preserving naturalness in the processed images to avoid decreasing the quality of vision (QOV) and state-of-the-art image recolouring methods succeeded in realising both contrast enhancement and naturalness preservation by utilising optimisation model. However, the high computational cost of these methods prevents their wide application in daily lives. Moreover, these methods cannot automatically resolve the trade-off between contrast enhancement and naturalness preservation. This paper proposes Optimized Dichromacy Projection (ODP) as a novel high-speed image recolouring technique for dichromacy compensation. ODP achieves both contrast enhancement and naturalness preservation by computing an optimized projection from the colour gamut of normal vision to the colour gamut of dichromacy and can automatically adapt the weight of contrast enhancement and naturalness preservation to the property of individual images. Qualitative, quantitative, and subjective evaluation experiments show that the proposed method can generate images of qualities competitive to the state-of-the-art methods while drastically improving computation time. [ABSTRACT FROM AUTHOR]

Purpose: Impact of color vision deficiency (CVD) on activities at school and productivity at work and consequential psychosocial difficulties has been reported. Although early detection and awareness help in overcoming these difficulties, screening for CVD is not a part of the school eye-screening initiatives in many countries. This study aimed at reporting the prevalence of CVD among school-going boys in Kanchipuram district, South India.Methods: The study was carried out as part of a school eye-screening program (SES) conducted in Kanchipuram district, Tamil Nadu, India for children between 6 and 17 years. The SES followed a three-phased protocol, which also included screening for CVD for all the boys between 11 and 17 years. The boys underwent CVD screening with Dalton's pseudo isochromatic plates (PIPs) followed by confirmation with Ishihara's PIP. The data were analyzed and the proportion of CVD in boys among different class grades, type of schools, location of schools, blocks of the district, and other clinical characteristics are presented.Results: Totally 250,052 children were screened in 1047 schools of which 74986 (60.61%) were boys between 11 and 17 years (mean age: 13.75 ± 1.91). The overall prevalence of CVD was found to be 2.76% (n = 2073; 95% confidence interval [CI]: 2.65-2.88). CVD was associated with urban locations (3.17% odds ratio [OR]: 1.90 95%CI: 1.69-2.13 P < 0.05) and public schooling (2.87%) (OR: 1.29 95%CI: 1.17-1.43 P < 0.05). Boys with CVD were less likely to have vision impairment (P = 0.002) and myopia (P < 0.001) as compared with boys with normal color vision. There was no significant difference in the proportion of other ocular conditions between children with and without CVD (P > 0.05).Conclusion: The study shows a significant proportion of CVD among boys in Kanchipuram district, India and its association with various demographic and clinical characteristics. Identification of CVD and counseling the stakeholders earlier through school children screening is crucial. [ABSTRACT FROM AUTHOR]

The primary goal of image color correction is to minimize color confusion for those people who experience deficiencies in their ability to distinguish certain colors. When the colors in a particular image are converted so as to make them perceivable to color vision deficient people, most of the existing methods correct all the colors of the image instead of only the specific colors that are confused. When ordinary people view the images converted using such techniques, they experience a significant difference in perception. To solve this problem, this study investigates the color perception of color vision deficient people through analysis of confused color regions in images and proposes a new method that corrects the minimum number of color regions into optimal colors. For this purpose, the proposed method builds a confusion line database for colors confused by color vision deficient people using the CIEDE2000 color-difference formula and Brettel's method for simulation of color vision deficiency in the offline stage. In the online processing stage, regions are divided through the region growing technique, and the colors in the divided images are compared. When there exist confused colors by color vision deficient people, a method for finding the optimal color is proposed through the confusion line database. Furthermore, this study developed an optimization index to propose a method of finding such optimal colors and validated them through various tests. The excellence of the color correction results of this study was demonstrated based on an objective index as well as on participants' subjective visual perception through comparative experiments with other existing studies.

Visual impairments often pose serious restrictions on a visually impaired person and there is a considerable number of persons, especially among aging population, which depend on assistive technology to sustain their quality of life. Development and testing of assistive technology for visually impaired requires gathering information and conducting studies on both healthy and visually impaired individuals in a controlled environment. We propose test setup for visually impaired persons by creating RFID based assistive environment - Visual Impairment Friendly RFID Room. The test setup can be used to evaluate RFID object localization and its use by visually impaired persons. To certain extent every impairment has individual characteristics as different individuals may better respond to different subsets of visual information. We use virtual reality prototype to both simulate visual impairment and map full visual information to the subset that visually impaired person can perceive. Time-domain color mapping real-time image processing is used to evaluate the virtual reality prototype targeting color vision deficiency. [ABSTRACT FROM AUTHOR]

Viola Andin Dohvoma, Stève Robert Ebana Mvogo, Giles Kagmeni, Nathalie Rosine Emini, Emilienne Epee, Côme Ebana Mvogo Department of Ophthalmology and ENT, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon Purpose: To determine the prevalence of color vision deficiency (CVD) among first-cycle students of the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé I.Patients and methods: A cross-sectional descriptive study was carried out between October 1, 2015 and May 31, 2016. Distant visual acuity was measured and color vision test done for all consenting students. Ishihara’s plates were used to test all the participants. Those who failed the test were tested with the Roth’s 28 Hue test for confirmation of CVD and classification.Results: A total of 303 students were included, among whom 155 were males (50.8%) and 148 were females (49.2%). The mean age was 20.2±2 years. Five students (1.6%) failed the Ishihara’s plate testing. Roth’s 28 Hue test confirmed CVD in 4 of those cases, giving a prevalence of 1.3%. There were equal numbers of protan and deutan CVD.Conclusion: Despite its low prevalence among first-cycle students of the Faculty of Medicine and Biomedical Sciences, CVD screening should be performed in order to raise awareness, which will go a long way to help orientate the choice of future specialty. Keywords: color vision deficiency, deutan, protan, biomedical students

About 250 million people in the world suffer from color vision deficiency (CVD). Contact lenses and glasses with a color filter are available to partially improve the vision of people with CVD. Tinted glasses uniformly change the colors in a user's field of view (FoV), which can improve the contrast of certain colors while making others hard to identify. On the other hand, an optical see-through head-mounted display (OST-HMD) provides a new alternative by applying a controllable overlay to a user's FoV. The method of color calibration for people with CVD, such as the Daltonization process, needs to make the calibrated color darker, which has not yet been featured on recent commercial OST-HMDs. We propose a new approach to realize light subtraction on OST-HMDs using a transmissive LCD panel, a prototype system, named ALCC-glasses, to validate and demonstrate the new arriving light chroma controllable augmented reality technology for CVD compensation. [ABSTRACT FROM AUTHOR]

The hypothesis that dichromatic behavior on a clinical anomaloscope can be explained by the complement and arrangement of the long- (L) and middle-wavelength (M) pigment genes was tested. It was predicted that dichromacy is associated with an X-chromosome pigment gene array capable of producing only a single functional pigment type. The simplest case of this is when deletion has left only a single X-chromosome pigment gene. The production of a single L or M pigment type can also result from rearrangements in which multiple genes remain. Often, only the two genes at the 5' end of the array are expressed; thus, dichromacy is also predicted to occur if one of these is defective or encodes a defective pigment, or if both of them encode pigments with identical spectral sensitivities. Subjects were 128 males who accepted the full range of admixtures of the two primary lights as matching the comparison light on a Neitz or Nagel anomaloscope. Strikingly, examination of the L and M pigment genes revealed a potential cause for a color-vision defect in all 128 dichromats. This indicates that the major component of color-vision deficiency could be attributed to alterations of the pigment genes or their regulatory regions in all cases, and the variety of gene arrangements associated with dichromacy is cataloged here. However, a fraction of the dichromats (17 out of 128; 13%) had genes predicted to encode pigments that would result in two populations of cones with different spectral sensitivities. Nine of the 17 were predicted to have two pigments with slightly different spectral peaks (usually < or = 2.5 nm) and eight had genes which specified pigments identical in peak absorption, but different in amino acid positions previously associated with optical density differences. In other subjects, reported previously, the same small spectral differences were associated with anomalous trichromacy rather than dichromacy. It appears that when the spectral difference specified by the genes is very small, the amount of residual red-green color vision measured varies; some individuals test as dichromats, others test as anomalous trichromats. The discrepancy is probably partly attributable to testing method differences and partly to a difference in performance not perception, but it seems there must also be cases in which other factors, for example, cone ratio, contribute to a person's ability to extract a color signal from a small spectral difference.

Purpose: This study was performed to investigate whether occupationally related color vision deficiency can occur from welding. Methods: A total of 50 male welders, who had been working as welders for at least 4 years, were randomly selected as case group, and 50 age matched non-welder men, who lived in the same area, were regarded as control group. Color vision was assessed using the Lanthony desatured panel D-15 test. The test was performed under the daylight fluorescent lamp with a spectral distribution of energy with a color temperature of 6500 K and a color rendering index of 94 that provided 1000 lx on the work plane. The test was carried out monocularly and no time limit was imposed. All data analysis were performed using SPSS, version 22. Results: The prevalence of dyschromatopsia among welders was 15% which was statistically higher than that of nonwelder group (2%) (p = 0.001). Among welders with dyschromatopsia, color vision deficiency in 72.7% of cases was monocular. There was positive relationship between the employment length and color vision loss (p = 0.04). Similarly, a significant correlation was found between the prevalence of color vision deficiency and average working hours of welding a day (p = 0.025). Conclusions: Chronic exposure to welding light may cause color vision deficiency. The damage depends on the exposure duration and the length of their employment as welders.

Color vision deficiency (CVD) is an extremely frequent vision impairment that compromises the ability to recognize colors. In order to improve color vision in a subject with CVD, we designed and developed a wearable improved vision system based on an augmented reality device. The system was validated in a clinical pilot study on 24 subjects with CVD (18 males and 6 females, aged 37.4 ± 14.2 years). The primary outcome was the improvement in the Ishihara Vision Test score with the correction proposed by our system. The Ishihara test score significantly improved ($p = 0.03$ ) from 5.8 ± 3.0 without correction to 14.8 ± 5.0 with correction. Almost all patients showed an improvement in color vision, as shown by the increased test scores. Moreover, with our system, 12 subjects (50%) passed the vision color test as normal vision subjects. The development and preliminary validation of the proposed platform confirm that a wearable augmented-reality device could be an effective aid to improve color vision in subjects with CVD.

Color vision deficiency (CVD) is a defect of vision with disability to distinguish colors. Color vision deficiency can be divided into the two categories, congenital and acquired. Congenital color vision deficiency divided into anomalous trichromacy, dichromacy and monochromacy. The most common congenital CVD was deuteranomalous that mode of inheritance is X linked recessive occurring mostly in males. Acquired CVD can occur as a direct result of illness or any related medicine. Color perception changes in acquired CVD may be secondary to primary ocular disease, drug side effect, or serious systemic disease such as diabetes. Dystrophy of cone, types of maculopathy, crystalline lens changes associated with aging, diabetes, glaucoma, optic nerve diseases and traumatic brain injuries can cause CVD. For acquired CVD, type of defect may not be easy to classify; nevertheless, predominantly is tritanopia and type and severity of the defect fluctuates during of disease. It has been suggested that human evolution to industrialized civilization has led to an increased prevalence of CVD in most population. An acquired CVD can reflect a deficiency in color information processing at anywhere along the related visual pathway, from the photoreceptors to the cortex. Sometimes, assessment of color vision can be helpful to detect a visual impairment in early stages.

In this paper, a novel method to modify color images for the protanopia and deuteranopia color vision deficiencies is proposed. The method admits certain criteria, such as preserving image naturalness and color contrast enhancement. Four modules are employed in the process. First, fuzzy clustering-based color segmentation extracts key colors (which are the cluster centers) of the input image. Second, the key colors are mapped onto the CIE 1931 chromaticity diagram. Then, using the concept of confusion line (i.e., loci of colors confused by the color-blind), a sophisticated mechanism translates (i.e., removes) key colors lying on the same confusion line to different confusion lines so that they can be discriminated by the color-blind. In the third module, the key colors are further adapted by optimizing a regularized objective function that combines the aforementioned criteria. Fourth, the recolored image is obtained by color transfer that involves the adapted key colors and the associated fuzzy clusters. Three related methods are compared with the proposed one, using two performance indices, and evaluated by several experiments over 195 natural images and six digitized art paintings. The main outcomes of the comparative analysis are as follows. (a) Quantitative evaluation based on nonparametric statistical analysis is conducted by comparing the proposed method to each one of the other three methods for protanopia and deuteranopia, and for each index. In most of the comparisons, the Bonferroni adjusted p-values are