Color Vision Impairment Research Articles

060 Impaired color discrimination is associated with hallucinations in dementia with lewy bodies

IntroductionEmerging evidence indicates that color discrimination impairments can predict the development of dementia across a range of prodromal Lewy body conditions. However, color vision deficits are not seen uniformly in patients with Dementia with Lewy Bodies (DLB), suggesting a more nuanced association. Visual hallucinations(VH) represent a discriminating feature of DLB, and recent evidence implicates visual pathway dysfunction as a significant contributor to this phenomenon. We therefore hypothesized that color impairment will more closely associate with VH in DLB rather than general cognition.MethodsIn this study, we examined the relationship between color vision impairment and VH, along with other clinical and neuropsychological features in 24 patients with DLB alongside 25 age-matched controls. Color discrimination was assessed using the Farnsworth-Munsell-100 Hue (FM-100) test.ResultsColor discrimination impairment was seen in 16/24 DLB participants (67%) with a higher error score relative to controls(p=0.001). We demonstrate for the first time a strong association between color discrimination errors and both the presence and severity of VH in DLB based on clinician-derived(p=0.008) and questionnaire-derived(p=0.03) measures. Correlation with clinical and neuropsychological variables revealed that color discrimination is significantly related to visuospatial impairment(p=0.02) but not to global measures of cognition, motor severity, age or disease duration. Factor analysis confirmed a unique relationship between color discrimination, visual hallucinations and visuospatial function.ConclusionOur results suggest that color impairments may be a specific biomarker of visual hallucinations and associated visuoperceptual deficits in evolving Lewy body disorders rather than dementia per se and thus providing insight into a shared pathophysiological substrate.

1548-P: High Prevalence of Glaucoma and Cataract with Uncommon Diabetic Retinopathy in Haitian Youth with Diabetes

Aim: Data on glaucoma and cataract in Afro-Caribbean youth with diabetes are scarce. We sought to determine the prevalence of ocular complications and their risk factors in a group of Haitian youth with diabetes. Methods: A cross-sectional study was conducted on youth aged 0-25 years with insulin-treated diabetes from one diabetes clinic in Haiti. We performed on both eyes visual acuity, Ishihara test, tonometry by Goldmann applanation, corneal pachymetry, slit lamp, refraction, gonioscopy, dilated fundoscopy and retinography, Humphrey visual field (VF), and spectral domain optical coherence tomography (Cirrus SD-OCT). We carried out Michigan Neuropathy Screening Instrument and neurothesiometer tests, and measured hemoglobin A1c (HbA1c), fasting lipid profile, and spot urinary albumin-to-creatinine ratio (UACR) twice 6 weeks apart. Primary open-angle glaucoma (POAG) was based on characteristic changes in: 1- optic disc, 2- retinal nerve fiber layer/combined macular ganglion cell and inner plexiform layers, 3- VF. Possible, suspected and overt POAG were diagnosed in the presence of 1, ≥ 2 and ≥ 2 criteria plus visual acuity loss, respectively. Results: We enrolled 51 patients: Age 18.4 ± 4.7 y, male 52.9%, diabetes duration 5.0 ± 3.2 y, HbA1c 11.2 ± 2.9%, normal lipid profile. Background diabetic retinopathy (DR), cataract, diabetic peripheral neuropathy, and increased UACR were found in 2.0%, 13.7%, 29.4%, and 7.8%, respectively. No color vision impairment was detected. Intraocular pressure was 17.3 ± 3.7 (R) and 17.1 ± 2.8 (L) mmHg. Ocular hypertension was found in 5.9%. POAG was overt in 3.9% and suspected in 17.7%. On regression analyses, none of the studied variables predicted POAG or cataract. Conclusion: POAG and cataract are common and precocious in Haitian youth with diabetes, without detectable risk factors. DR is uncommon. Comprehensive eye examination with VF and OCT when available is suggested early after diabetes diagnosis. Disclosure E. Jean Baptiste: None. P. Larco: None. M. Charles Larco: None. J.E. von Oettingen: None. F. Rocourt: None. B. Hudicourt: None. K. Moise: None. R. Paul: None. R. Charles: None.

Evolution of prodromal Parkinson's disease and dementia with Lewy bodies: a prospective study.

Parkinson's disease has a long prodromal stage with various subclinical motor and non-motor manifestations; however, their evolution in the years before Parkinson's disease is diagnosed is unclear. We traced the evolution of early motor and non-motor manifestations of synucleinopathy from the stage of idiopathic rapid eye movement (REM) sleep behaviour disorder until defined neurodegenerative disease. During 2004-16, we recruited and then annually followed 154 polysomnography-proven patients with idiopathic REM sleep behaviour disorder, of whom 55 phenoconverted to defined parkinsonism or dementia. Longitudinal data on multiple prodromal features, including the Unified Parkinson's Disease Rating Scale parts I-III, quantitative motor tests, olfaction, colour vision, cognition, and autonomic functions were gathered annually (average = five follow-up visits, range: 2-12 years). The same measures were also assessed in 102 age- and sex-matched healthy control subjects. By looking backward from the time of dementia or parkinsonism diagnosis, we examined trajectories of each prodromal feature using mixed effect models. Based on analysis, olfactory loss was first to develop, with predicted onset >20 years before phenoconversion. This was followed by impaired colour vision, constipation, and erectile dysfunction, starting 10-16 years prior to phenoconversion. At 7-9 years before phenoconversion, slight urinary dysfunction and subtle cognitive decline could be detected. Among motor symptoms altered handwriting, turning in bed, walking, salivation, speech, and facial expression began to be disrupted starting 7-11 years prior to parkinsonism diagnosis, but remained mild until soon before phenoconversion. Motor examination abnormalities began 5-7 years before phenoconversion, with the alternate tap test having the longest interval (8 years before phenoconversion). Among cardinal motor phenotypes, bradykinesia appeared first, ∼5-6 years prior to phenoconversion, followed by rigidity (Year -3) and tremor (Year -2). With direct prospective evaluation of an idiopathic REM sleep behaviour disorder cohort during phenoconversion, we documented an evolution of prodromal manifestations similar to that predicted by pathological staging models, with predicted prodromal intervals as long as 20 years.

Color vision study to assess the impaired retina-brain cortex pathway in type 2 diabetes: a pilot study in Calabria (Southern Italy).

The present pilot study was undertaken to investigate the impaired acquired color vision on Calabrian male sample showing this parameter as a biological marker in type 2 diabetes. All patients and controls underwent three pseudo-isochromatic clinical test batteries: Ishihara test, Farnsworth test, and City University test. The results show a specific loss of short-wavelength (blue sensitivity) and typical tritan responses in diabetic patients. Generally, in later stages of the disease, the red-green mechanisms are involved. By the impaired color vision study in diabetic patients, we can confirm the impaired retina-brain cortex pathway. We believe that the above not invasive test analysis can support the other instrumental and imaging analysis to study the impaired retina-brain cortex pathway. Moreover, we think that the present clinical method can be useful in terms of preventive medicine.

Impaired Color Discrimination-A Specific Marker of Hallucinations in Lewy Body Disorders.

There is emerging evidence indicating that color discrimination impairments can predict the development of Lewy body dementia in patients with rapid eye movement sleep behavior disorder, Parkinson disease, and in patients with mild cognitive impairment. Despite this clear relationship, color vision deficits are not seen uniformly in patients with dementia with Lewy bodies (DLB), suggesting a more nuanced association with the underlying neuropathology. Visual hallucinations represent a discriminating feature of DLB, and recent evidence implicates visual pathway dysfunction as a significant contributor to this phenomenon. In this study, we examined the relationship between color vision impairment and visual hallucinations, along with other clinical and neuropsychological features in 24 well-characterized patients with DLB alongside 25 healthy controls. Color discrimination impairment was seen in 16 (67%) of 24 DLB participants with a higher error score relative to controls (P = .001). We demonstrate for the first time a strong association between color discrimination errors on the Farnsworth-Munsell 100 hue test and both the presence and severity of hallucinatory symptoms in DLB based on clinician-derived (P = .008) and questionnaire-derived (P = .03) measures. Correlation with clinical and neuropsychological variables revealed that color discrimination is significantly related to visuospatial difficulties measured by the clock-drawing task (P = .02) but not to global measures of cognition, motor severity, age, or disease duration in our cohort. Factor analysis confirmed a unique relationship between color discrimination, visual hallucinations, and visuospatial function. Our results suggest that color discrimination does not simply relate to dementia but rather indexes higher order perceptual deficits that may predict visual hallucinations in Lewy body disorders and share a common pathophysiological substrate.

Ophthalmological manifestation in patients of tuberculous meningitis.

Vision impairment, blindness in particular is a devastating complication in patients with tuberculous meningitis. However, information regarding ophthalmological manifestation and its impact on vision is sparse in the literature. This study evaluated the spectrum of ophthalmological manifestations in tuberculous meningitis, including retinal nerve fiber layer thickness assessment by optic coherence tomography and its correlation with visual and clinical outcome. This was a prospective observational study done from October 2015 to March 2017. Consecutive patients of tuberculous meningitis, diagnosed as per consensus case definition were included in the study. The patients were divided into two categories: uncomplicated and complicated tuberculous meningitis. Clinical evaluation, cerebrospinal fluid examination and contrast enhanced MRI of brain was done. Detailed ophthalmological evaluation including optic coherence tomography was done in all patients. All the patients were followed for 6 months. The primary outcome was blindness or low vision after 6 months. The secondary outcome was death or severe disability after 6 months. It was defined as modified Barthel index (MBI) ≤ 12 at 6 months (including disability plus death). Appropriate statistical analysis was done. Out of 101 patients of tuberculous meningitis, 47 patients of TBM belonged to uncomplicated category, while 54 patients were of complicated group. The visual impairment was present in 24 out of 101 (23.76%) patients out of which 20 (19.8%) patients had low vision while 4 (3.96%) had blindness. The visual impairment was more evident in complicated group, low vision 0.03 (1.2-31.5). The most common abnormality on fundus examination was papilledema (22.8%). The complicated group had more incidence <0.0001 (19.6-48). Optic atrophy was found in three patients while choroid tubercles were found in eight patients (all complicated TBM group). RNFL thinning was noted in 10 patients in both the eyes. On univariate analysis, presence of diplopia at baseline, impairment of color vision at baseline, visual impairment at baseline, cranial nerve VIth involvement, optic atrophy and papilledema at baseline, RNFL thinning, abnormal VEP and baseline MBI were associated with poor visual outcome. On multivariate analysis, none of the factors were found to be independently associated with poor visual outcome. On univariate analysis, many factors including baseline MRC staging, altered sensorium, seizure, hemiparesis, basal exudates, infarcts, optochiasmaticarachnoiditis, visual impairment at baseline were found to be associated with poor clinical outcome at 6 months. On multivariate analysis, presence of seizure (P = 0.047, odds ratio = 78.59, 95% confidence interval (1.07-578.72)) was the only factor found to be independently associated with poor outcome. Wide spectrum of ophthalmological manifestation was observed in patients of tuberculous meningitis. The visual impairment was more evident in complicated tuberculous meningitis. Ophthalmological findings like optic atrophy, papilledema and RNFL thinning were associated with poor visual outcome on univariate but not multivariate analysis. Visual impairment at baseline, among other factors was associated with poor clinical outcome on univariate analysis, whereas seizure was the only factor independently associated with poor outcome on multivariate analysis.

Dichromacy: Color Vision Impairment and Consanguinity in Heterogenous Population of Pakistan

Dichromacy: Color Vision Impairment and Consanguinity in Heterogenous Population of Pakistan

Dichromacy: Color Vision Impairment and Consanguinity in Heterogenous Population of Pakistan

Abstract:&#x0D; Background and Objectives: Dichromacy, an X-linked recessive disorder is identified worldwide, more in males than females. In European Caucasians, its incidence is 8% in males and 0.5% in females. In India, it is 8.73% in males and 1.69% in females, and in Iran, it is 8.18% in males and 0.43% in females. Population based epidemiological data about dichromacy in different ethnic groups in Pakistan is not available. The aim of this study was to find out the population prevalence of inherited red-green dichromacy in a heterogenous population of the district of Chiniot, Punjab, Pakistan, and to determine the impact of consanguinity and ethnicity.&#x0D; Methods: In this cross-sectional study, boys and girls of the higher secondary schools were examined in the three tehsils of district Chiniot. Pseudoisochromatic Ishihara Test has been employed for detection of dichromacy in the study population. The sample size was calculated statistically as 260, which was expanded to 705 and divided by population density of the three tehsils.&#x0D; Results: Screening of 359 males and 346 females revealed 19 (5.29%) dichromat males and only 2 (0.58%) females. The study population belonged to 23 castes / isonym groups. The consanguinity found in the district of Chiniot is 84.82% and in the dichromat families, it is 85.71%, of which 52.37% are first cousin.&#x0D; Interpretation &amp; Conclusion: The study has shown that the incidence of dichromacy could be reduced through genetic counseling

Dichromacy: Color Vision Impairment and Consanguinity in Heterogenous Population of Pakistan

Dichromacy: Color Vision Impairment and Consanguinity in Heterogenous Population of Pakistan

Percepção Visual no Tremor Essencial: Uma Revisão Sistemática

RESUMO Investigou-se a relação entre percepção visual e tremor essencial (TE). Realizou-se uma revisão dos estudos publicados sobre o tema nas bases de dados PubMed, BIREME, CINAHL, Web of Science, PsycINFO, SciELO, SCOPUS e ELSEVIER desde a origem até 05 de janeiro de 2017. A triagem, extração de dados e avaliação foram realizadas por dois revisores. Para avaliar a qualidade dos estudos utilizou-se as diretrizes do National Institutes of Health (NIH). De 132 estudos potencialmente elegíveis, 12 foram selecionados de acordo com os critérios de elegibilidade. Os resultados indicaram que pessoas com TE apresentam baixa sensibilidade visual quando comparados com indivíduos saudáveis, apesar de não apresentarem prejuízos na visão de cores. Apesar da heterogeneidade dos dados, observamos que existem prejuízos visuais em pessoas com TE e estes podem ser uma das principais características clínicas não-motoras.

Effectiveness of a protocol for teaching dental tooth color in students with color vision impairment.

In patients with color vision alterations (CVA), the correct determination of color is altered, but not the detection of changes in luminosity or value. There is no accepted training protocol for dental value selection in dental students with CVA. The objective of this pilot study was to determine the effectiveness of a dental color training protocol based on the dental value selection. An intervention study was carried out on dental students in a University setting, applying a specific dental color training protocol on two groups of students. Group 1:4 students with CVA, Group 2:4 healthy students. A third group of four students without intervention was used as a control group. An initial diagnostic test was applied, which was reapplied at the end of the training. The number of errors in the selection of the dental color decreased after training in all three groups, P > .05. For the value parameter, there was a statistically significant decrease in the number of errors after training (P = .014). The applied training protocol could be of help in students with CVA, but multicenter studies are needed. Level 3 evidence level.

Subthreshold lasercoagulation (810 nm) for diabetic macular edema

Introduction. The threshold laser coagulation leads to irreversible damage of retinal structures, microscotomata appearance in the central visual field, contrast sensitivity decrease, and color vision impairment, being accompanied as well by the release of proinflammatory cytokines. For diabetic macular edema treatment, a method of high-density subthreshold laser coagulation (810 nm) was first developed, based on individualized choice of subthreshold parameters of laser irradiation, and permitting confluent application of laser impacts to the retina. Using multimodal diagnostic approach to the estimation of anatomic and functional treatment results, a minimally invasive character and safety of this DME treatment method were confirmed.&#x0D; Purpose. The aim of this study was to comparatively evaluate the efficacy of a diode laser (810 mn) subthreshold laser treatment using high-density laser impact application in diode laser coagulation (DLC) and diode microphotocoagulation (DMP) modes.&#x0D; Materials and methods. To compare the efficacy of subthreshold laser treatment methods (DLC and DMP), patients were divided into two groups, comparable in macular edema thickness and area. The first group (24 eyes) received a macular laser coagulation in grid pattern and MicroPulse diode laser (810 nm) regimen; biomicroscopically it was predominantly subthreshold high-density application of burns. The second group (29 eyes) received a macular laser coagulation in grid pattern and continuous diode laser (810 nm) regimen; biomicroscopically it was predominantly subthreshold high-density application of burns.&#x0D; Results. After DLC and DMP, there was no statistically significant difference between compared groups in best corrected visual acuity. There was also no significant difference in retinal edema maximal height dynamics, retinal edema area, and central thickness in 2 and 4 months.&#x0D; Conclusion. Subthreshold microphotocoagulation and laser coagulation methods at the same average power of laser exposure and other exposure parameters in the shortterm follow-up have comparable efficacy in the treatment of diabetic macular edema.

Prevalence of color blindness among school children in three primary schools of Gish \u2013Abay town district, Amhara regional state, north-west Ethiopia

BackgroundAlthough there are limited studies, recent data are lacking to accurately determine the magnitude of color blindness in Ethiopia and there is no evidence of such a study in Gish Abay town district. The purpose of thie study was to assess the prevalence of color blindness among school children in Gish Abaya town district, Ethiopia.MethodsThe study used a community-based analytical cross-sectional study design with multistage cluster random sampling technique from September to October 2016. Three primary schools were selected randomly in the district of Gish Abay town district. Ishihara color plates (24 –edition) was used for color vision test and Snellen’ tumbling ‘E’ chart was used for visual acuity test. The data was analyzed using Statistical Package for Social Sciences (SPSS) version 20 statistical software and binary logistic regression was used to identify factors associated with color blindness.ResultsAmong a total of 854 subjects, 850 participants with age range of 8–18 years were screened for color vision test giving a response rate of 99.53%. Among the participants, 452 (53.2%) were males and 398 (46.8%) were females. There were 36 (4.24%) cases of impaired color vision. Among these, 27 (3.18%) were males and 9 (1.06%) were females. Out of 36 cases of color blindness, 15 (1.77%) were deutan, 7 (0.82%) were protan and 14(1.65%) were unclassified (both deutan and protan forms). The variables; sex adjusted odds ratio (AOR [95% Confidence Interval] =3.19 [1.45; 6.98], p-value = 0.004); and visual impairment (AOR [95% CI] =4.15 [1.77; 9.75], p-value = 0.001) were significantly associated with color impairment.ConclusionThe prevalence of childhood color blindness in Gish Abay town district was relatively similar with other studies in Ethiopia. Sex and visual impairment are factors found to be related with the children’s color blindness. Periodical eye examination at the time of school admission is recommended to adjust the children’s occupation early in life.

Levamisol-induced leukoencephalopathy: clinical case

This is a description of a clinical case of levamisole-induced leukoencephalopathy. A few hours after the single intake of the immunomodulator levamisole (150 mg), the patient developed following cerebral symptoms: febrile fever, dizziness, frequent urination, impaired color vision, divergent strabismus, unsteady gait, severe weakness, increased drowsiness, retardation, delusions. The symptoms progressed towards a full clinical picture for about 2 months. The course of the disease was of a wavy nature: left-sided hemiparesis and the left facial nerve palsy were present at the beginning, with later inversion of symptoms represented by the right-sided hemiparesis and the right facial nerve palsy combined with dysarthria. Magnetic resonance imaging (MRI) revealed multiple foci of demyelination in both hemispheres of the brain that regressed after corticosteroid therapy administration. No abnormalities of the cerebrospinal fluid were detected. No pathology of the fundus was evident. The evoked potentials of the brainstem (auditory and visual) and somatosensory evoked potentials from the hands and feet were within normal limits. Plasmapheresis (3 procedures, each 2 liter, with intravenous administration of 1 g of solu-medrol after each session) was performed in the acute phase, which benefited the decrease in severity of the neurological symptoms. Vascular and metabolic therapy was performed afterwards, with the regression of the neurologic symptoms. No specific therapy was administered after the woman was discharged from the hospital. For a 10-year survey after the acute demyelinating process outbreak there’s a complete regression of neurologic symptoms and positive dynamics of the patient’s MRI. The woman is fully adapted physically, emotionally and socially.

Color vision impairments in schizophrenia and the role of antipsychotic medication type

Schizophrenia patients (SCZ) demonstrate deficits in many domains of mental functioning, including visual perception. An issue that has been relatively unexplored, in terms of explaining variation in visual function in SCZ, however, is medication use. The present study explored potential medication effects on color vision in SCZ, a process that is strongly linked to dopaminergic function in the retina. SCZ patients who had clear-cut either typical (n = 29) or atypical (n = 29) monotherapy, without any other concurrent medication, and a group of age- and gender-matched healthy controls participated in the study. Color vision was assessed by the Cambridge Colour Test, using the Trivector and Ellipse subtests. The results demonstrated impaired color perception in patients with schizophrenia, especially in those receiving typical antipsychotics, but these deficits were subtle and not generalized to all parameters. Our findings are consistent with the known neurophysiology of the retina and visual pathways, and with the effects of dopamine blocking medications, but the results should be carefully interpreted.

A comparison of intraoral spectrophotometers-Are there user-specific differences?

The objective of this study was to determine the potential impact of a positioning splint on the determination of the correct tooth color using VITA Easyshade 4 (VE4) or VITA Easyshade 5 (VE5) (VITA Zahnfabrik, Germany). Dental students (n = 50) in their third year and one expert determined the tooth shade of an extracted human tooth using VE4 and VE5, in presence or absence of a positioning splint. The determined shade values (L*a*b*) were collected and the delta E was calculated. A statistical evaluation was performed with the program SPSS® (P < .05). There was no significant difference in the determination of the correct tooth color (VITA 3D-Master shade), independent from either the expert or the students positioning splint, and independent of using VE4 (P = 1; P = .092) or VE5 (P = .125; P = .25). Using VE4 or VE5, a positioning splint has no effect on the determination of the correct tooth color (VITA 3D-Master shade). For an exact measurement of the L*a*b values in clinical studies, a positioning splint should be used. A person untrained in working with the devices can determine the correct tooth shade more frequently with VE5 than with VE4.© 2018 Wiley Periodicals, Inc. Correctly determining the tooth shade is an essential treatment step in esthetic reconstructive dentistry. Color is probably one of the most important determinants of esthetics in dentistry. Factors such as lighting conditions, gender, age, experience, and color vision impairment affect the process of shade matching. These deficits brought about the desire for an objective and reproducible shade determination method with digital devices for shade determination. One of the most proven and frequently used digital shade determination devices is the "VITA Easyshade" (VITA Zahnfabrik, Bad Säckingen, Germany). At this point in time, there are no (published) reports on the measurement accuracy of the new VE 5. In addition, there are, as of yet, no investigations comparing the VE 4 and VE 5.

Non-motor features of Parkinson’s disease in a nested case–control study of US men

BackgroundSeveral non-motor features may individually contribute to identify prodromal Parkinson’s disease (PD), but little is known on how they interact.MethodsWe conducted a case–control study nested within the Health Professionals Follow-up...

No blue-yellow color vision impairment after acute ethanol ingestion.

Several studies showed that chronic ethanol exposure can cause color vision deficiencies. There has been no agreement about the axis of color defects due to alcohol misuse since changes in the red-green and the blue-yellow axis have been described in literature. The acute influence of alcohol on the blue-yellow color vision has not been studied as well. The aim of this study was to determine the effect of acute alcohol ingestion on blue-yellow color vision by using short wavelength automated perimetry (SWAP) and anomaloscopy with the Moreland equation. This is the first study evaluating that question by using SWAP and anomaloscopy. Sixteen healthy subjects without a history of alcohol-related and ophthalmological problems were examined by SWAP and anomaloscopy (Moreland equation) before and after alcohol ingestion. Mean sensitivity (MS), mean deviation (MD), loss of variance (LV), reliability factor (RF), and duration of examination were assessed for perimetry and match midpoint (MP), matching range (MR), and duration of examination for anomaloscopy. Blood alcohol concentrations (BAC) were determined by gas chromatography and phosphatidylethanol concentrations (marker of an alcohol misuse) by liquid-chromatography tandem-mass spectrometry in venous blood samples from a cubital vein. Mean blood BAC was 0.86±0.20g/kg while performing perimetry and 0.84±0.20g/kg while performing anomaloscopy (BAC: 0.1g/kg≈0.01g/dL). MS, MD, RF, MP, MR, and duration of perimetry examination were not altered significantly after alcohol intake. LV showed a significant increase. The duration of anomaloscope testing was shortened significantly under the influence of alcohol. The subjects also revealed a significantly narrower matching range after alcohol intake. In the range of 0.8g/kg BAC, no blue-yellow vision deficiencies could be demonstrated. In further studies, the effect of higher BAC on blue-yellow vision should be investigated by different methods.

Accessible maps for the color vision deficient observers: past and present knowledge and future possibilities

Abstract. Color is part of the visual variables in map, serving an aesthetic part and as a guide of attention. Impaired color vision affects the ability to distinguish colors, which makes the task of decoding the map colors difficult. Map reading is reported as a challenging task for these observers, especially when the size of stimuli is small. The aim of this study is to review existing methods for map design for color vision deficient users. A systematic review of research literature and case studies of map design for CVD observers has been conducted in order to give an overview of current knowledge and future research challenges. In addition, relevant research on simulations of CVD and color image enhancement for these observers from other fields of industry is included. The study identified two main approaches: pre-processing by using accessible colors and post-processing by using enhancement methods. Some of the methods may be applied for maps, but requires tailoring of test images according to map types.

Color Vision in Aniridia.

PurposeTo assess color vision and its association with retinal structure in persons with congenital aniridia.MethodsWe included 36 persons with congenital aniridia (10–66 years), and 52 healthy, normal trichromatic controls (10–74 years) in the study. Color vision was assessed with Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates (4th ed., 2002); Cambridge Color Test and a low-vision version of the Color Assessment and Diagnosis test (CAD-LV). Cone-opsin genes were analyzed to confirm normal versus congenital color vision deficiencies. Visual acuity and ocular media opacities were assessed. The central 30° of both eyes were imaged with the Heidelberg Spectralis OCT2 to grade the severity of foveal hypoplasia (FH, normal to complete: 0–4).ResultsFive participants with aniridia had cone opsin genes conferring deutan color vision deficiency and were excluded from further analysis. Of the 31 with aniridia and normal opsin genes, 11 made two or more red-green (RG) errors on HRR, four of whom also made yellow-blue (YB) errors; one made YB errors only. A total of 19 participants had higher CAD-LV RG thresholds, of which eight also had higher CAD-LV YB thresholds, than normal controls. In aniridia, the thresholds were higher along the RG than the YB axis, and those with a complete FH had significantly higher RG thresholds than those with mild FH (P = 0.038). Additional increase in YB threshold was associated with secondary ocular pathology.ConclusionsArrested foveal formation and associated alterations in retinal processing are likely to be the primary reason for impaired red-green color vision in aniridia.