Colour Vision Impairment in Young Alcohol Consumers

Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency

Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.

Bacteria in the oral cavity of individuals consuming intoxicating substances

Food habits and oral hygiene are critical attributes for physiochemical environment of the oral cavity. Consumption of intoxicating substances such as betel nut ('Tamul'), alcohol, smoking and chewing tobacco may strongly influence the oral ecosystem including commensal microbes. Therefore, a comparative assessment of microbes in the oral cavity between individuals consuming intoxicating substances and non-consumers may indicate the influence of these substances. Oral swabs were collected from consumers of intoxicating substances and non- consumers of Assam, India, microbes were isolated by culturing on Nutrient agar and identified by phylogenetic analysis of their 16S rRNA gene sequences. The risks of consumption of intoxicating substance on occurrence of microbes and health conditions were estimated using binary logistic regression. Mostly pathogens and opportunistic pathogens were found in the oral cavity of consumers and oral cancer patients which included Pseudomonas aeruginosa, Serratia marcescens, Rhodococcus antrifimi, Paenibacillus dendritiformis, Bacillus cereus, Staphylococcus carnosus, Klebsiella michiganensis and Pseudomonas cedrina. Enterobacter hormaechei was found in the oral cavity of cancer patients but not in other cases. Pseudomonas sp. were found to be widely distributed. The risk of occurrence of these organisms were found in between 0.01 and 2.963 odds and health conditions between 0.088 and 10.148 odds on exposure to different intoxicating substances. When exposed to microbes, the risk of varying health conditions ranged between 0.108 and 2.306 odds. Chewing tobacco showed a higher risk for oral cancer (10.148 odds). Prolonged exposure to intoxicating substances conduce a favorable environment for the pathogens and opportunistic pathogens to colonize in the oral cavity of individuals consuming intoxicating substances.

Comprehensive visual electrophysiological measurements discover crucial changes caused by alcohol addiction in humans: Clinical values in early prevention of alcoholic vision decline

Alcohol addiction often compromises vision by impairing the visual pathway, particularly the retina and optic nerve. Vision decline in alcoholics consists of a sequential transition from reversible functional deterioration of the visual pathway to irreversible clinical vision degeneration or vision loss. Thus, the control of alcoholic vision decline should focus on prevention before permanent damage occurs. Visual electrophysiology is a promising method for early detection of retinal dysfunction and optic neuropathy, including full-field electroretinography (ffERG) and pattern-reversal visual evoked potential (PR-VEP). So far, however, research studying the electrophysiological characteristics in the preclinical stage of vision decline caused by alcohol addiction is still lacking. Here we conducted a retrospective study with 11 alcoholics and 14 matched control individuals to address this need. We had performed comprehensive visual electrophysiological tests, including ffERG and PR-VEP. We next analyzed all electrophysiological parameters using multivariate statistical analyses and discovered some highly sensitive alterations to alcohol addiction. We found severely reduced amplitudes in scotopic ffERG oscillatory potentials (OPs) in alcohol addicts. These changes indicate the alcohol-induced disturbances of amacrine cells and retinal circulation. In subjects with alcohol addiction, the amplitudes of b-waves diminish significantly in scotopic but not photopic ffERG, implying the impaired function of the retinal rod system and the dysfunction of the inner retina. PR-VEPs elicited by checkerboard stimuli with large 1 degree (°) checks mainly reflect the state of the optic nerve and ganglion cells, and PR-VEPs provoked by small 0.25° checks mainly reflect the function of the macular. We performed both measurements and observed a robust amplitude reduction in all three peaks (N75–P100, P100–N135) and a significant peak time extension in P100. Our research provides an affordable and non-invasive tool to accurately evaluate visual pathway conditions in alcohol addicts and help clinicians take targeted treatment.

A Dose–Response Relationship of Alcohol Consumption with Risk of Visual Impairment in Korean Adults: The Kangbuk Samsung Health Study

Visual impairment is a global health problem that leads to poor quality of life. The aim of the study was to examine the dose–response relationship between alcohol consumption and incident visual impairment (VI). This longitudinal cohort study consisted of 287,352 Korean adults who attended health screenings between March 2011 and December 2017 and were followed for up to 8.8 years (median, 4.9 years). Participants were categorized based on their average alcohol consumption. VI was defined as bilateral visual acuity (VA) worse than 0.3 logMAR. We identified 8320 cases of new-onset bilateral VI (incidence rate, 6.0/1000 person-years). Increased alcohol intake was positively and dose-dependently associated with elevated incidence of VI (p_trend < 0.001). With lifetime abstinence (reference), the multivariable-adjusted hazard ratios (HRs) (95% confidence intervals (CIs)) for incident VI with alcohol intake of <10, 10 to <20, 20–39.9, and ≥40 g/day were 1.07 (0.96–1.19), 1.15 (1.03–1.30), 1.15 (1.01–1.30), and 1.23 (1.08–1.40), respectively. Frequent binge drinking (≥once/per week) was associated with elevated risk of VI (HRs, 1.22; 95% CIs: 1.13–1.32). Former drinkers, particularly men, were at a higher risk for incident VI than lifetime abstainers. Similar associations were observed on evaluating changes in alcohol consumption and other confounders as time-varying covariates. Alcohol consumption, both in moderation and excess, was associated with increased VI incidence.

The influence of alcohol intake in myopia development or progression: The SUN cohort study

BACKGROUND

Myopia is a highly prevalent disorder, and one of the first causes of blindness. In turn, alcohol consumption has been shown to be a risk factor for many diseases and a main contributor to the global burden of disease. However, no studies have investigated the relationship between alcohol intake and myopia. Our aim was to prospectively assess the association between alcohol intake and the development or progression of myopia.

METHODS

In a Spanish dynamic prospective cohort (the SUN Project) we assessed 15,642 university graduates, recruited between 1999 and 2018 and followed up biennially through mailed questionnaires. Alcohol intake was assessed with a validated 136-item food frequency questionnaire. Development or progression of myopia was collected in subsequent questionnaires during follow-up every two years.

RESULTS

Alcohol intake was linearly and significantly associated with a higher risk of myopia development or progression: the OR for 10-year incidence/progression of myopia was 1.05, 95% CI 1.01-1.09 per each 10-grams increase in alcohol intake.

CONCLUSIONS

Alcohol consumption might lead to the development or progression of myopia, although confirmation is needed for the mechanisms through which this association may occur, thus further research is needed to verify these findings.

Alcohol and the Eye

In this article, we present a review of ocular conditions related to alcohol consumption. A search of the literature published from 1952 to March 2020 was performed. The titles and abstracts were screened and the eligible studies were selected. PubMed, ISI Web of Knowledge database, Scopus, Embase, and the Cochrane Library were searched. We categorized the relationship between alcohol intake and ocular conditions by the type of ocular exposure to alcohol. Accordingly, ocular findings following acute alcohol intoxication, optic neuropathy following methanol toxicity, congenital conditions related to maternal alcohol consumption, and ocular disease related to chronic alcoholism are discussed. The main feature of alcohol intoxication in the eye is abnormal eye movement. Acute optic neuropathy secondary to methyl alcohol consumption is a serious ocular disease with permanent vision loss or scotoma. Prenatal exposure to ethanol may end in fetal alcohol spectrum disease, where ocular findings are a constant component. The association between chronic alcohol consumption and increased risks of cataract, age-related macular degeneration, diabetic retinopathy, different types of optic neuropathy, impairment of visual quality, retinal vascular disease, and ocular surface disease has also been reported. Along with detrimental medical and social effects, the role of alcohol consumption in different ocular conditions should be considered, as alcohol-induced visual disturbances may contribute to the heavy burden of alcohol abuse on the healthcare system and overall quality of life.

Visual function and psychological variables in alcohol dependency syndrome

INTRODUCTION

Alcohol Dependence Syndrome (ADS) is defined as excessive alcohol consumption accompanied by psychological, physical, social, and economic disorders. Alcohol consumption affects motor and proprioceptive functions, decreasing motor and cognitive functions and causing attention deficits. We aim to evaluate visual function and attention, and psychological profiles in consumer and abstainer ADS patients.

METHODS

This quantitative, descriptive, cross-sectional and correlational study evaluates visual function in a sample of ADS patients. The Portuguese version of the Brief Symptom Inventory was used to assess patients' psychological status. The orthoptic examination protocol for visual function consisted of 11 standardized tests: VA for distance and near, ocular movements, near convergence and accommodation point, cover and prismatic cover tests, fusional vergence for distance and near, near stereoacuity, chromatic vision, contrast sensitivity and visual attention.

RESULTS

The sample included 176 patients. 121 were consumers and 55 were abstainers, aged between 31 and 72. The most affected parameters of visual function were visual acuity (80.39%), contrast sensitivity (67.50%), convergence at distance (66.44%) and near stereopsis (62.75%). Visual function was impacted in both groups. Regarding psychological status, consumers had higher averages for the Depression subscale, followed by Paranoid Ideation and Obsession. Abstainers had the highest averages in the Obsession subscale, followed by Paranoid Ideation and Depression. Statistically significant differences existed between the groups in the subscales for depression (p=.046) and paranoid ideation (p =.042).

CONCLUSION

Changes in visual function and attention, as well as psychopathological function, should be considered in the rehabilitation of ADS patients.

Magnocellular and Parvocellular Mediated Luminance Contrast Discrimination in Severe Alcohol Use Disorder

BACKGROUND

Severe alcohol use disorder (SAUD) is associated with widespread cognitive impairments, including low-level visual processing deficits that persist after prolonged abstinence. However, the extent and characteristics of these visual deficits remain largely undetermined, impeding the identification of their underlying mechanisms and influence on higher-order processing. In particular, little work has been conducted to assess the integrity of the magnocellular (MC) and parvocellular (PC) visual pathways, namely the 2 main visual streams that convey information from the retina up to striate, extrastriate, and dorsal/ventral cerebral regions.

METHODS

We investigated achromatic luminance contrast processing mediated by inferred MC and PC pathways in 33 patients with SAUD and 32 matched healthy controls using 2 psychophysical pedestal contrast discrimination tasks that promote responses of inferred MC or PC pathways. We relied on a staircase procedure to assess participants' ability to detect small changes in luminance within an array of 4 gray squares that were either continuously presented (steady pedestal, MC-biased) or briefly flashed (pulsed pedestal, PC-biased).

RESULTS

We replicated the expected pattern of MC and PC contrast responses in healthy controls. We found preserved dissociation of MC and PC contrast signatures in SAUD but higher MC-mediated mean contrast discrimination thresholds combined with a steeper PC-mediated contrast discrimination slope compared with healthy controls.

CONCLUSION

These findings indicate altered MC-mediated contrast sensitivity and PC-mediated contrast gain, confirming the presence of early sensory disturbances in individuals with SAUD. Such low-level deficits, while usually overlooked, might influence higher-order abilities (e.g., memory, executive functions) in SAUD by disturbing the "coarse-to-fine" tuning of the visual system, which relies on the distinct functional properties of MC and PC pathways and ensures proper and efficient monitoring of the environment.

Effects of Chronic Alcohol Use Disorder on the Visual Tilt Illusion

Rationale: Among the serious consequences of alcohol use disorder (AUD) is the reduced ability to process visual information. It is also generally agreed that AUD tends to occur with disturbed excitation-inhibition (EI) balance in the central nervous system. Thus, a specific visual behavioral probe could directly qualify the EI dysfunction in patients with AUD. The tilt illusion (TI) is a paradigmatic example of contextual influences on perception of central target. The phenomenon shows a characteristic dependence on the angle between the inducing surround stimulus and the central target test. For small angles, there is a repulsion effect; for larger angles, there is a smaller attraction effect. The center-surround inhibition in tilt repulsion is considered to come from spatial orientational interactions between orientation-tuned neurons in the primary visual cortex (V1), and tilt attraction is from higher-level effects of orientation processing in the visual information processing. Objectives: The present study focuses on visual spatial information processing and explores whether chronic AUD patients in abstinence period exhibited abnormal TI compared with healthy controls. Methods: The participants are 30 male volunteers (20-46 years old) divided into two groups: the study group consists of 15 clinically diagnosed AUD patients undergoing abstinence from alcohol, and the control group consists of 15 healthy volunteers. The TI consists of a center target surround with an annulus (both target and annulus are sinusoidal grating with spatial frequency = 2 cycles per degree). The visual angle between center and surround is a variable restricted to 0°, ±15°, ±30°, or ±75°. For measuring the TI, participants have to report whether the center target grating orientation tilted clockwise or counterclockwise from the internal vertical orientation by pressing corresponding keys on the computer keyboard. No feedback is provided regarding response correctness. Results: The results reveal significantly weaker tilt repulsion effect under surround orientation ±15° (p < 0.05) and higher lapse rate (attention limitation index) under all tested surround orientations (all ps < 0.05) in patients with chronic AUD compared with health controls. Conclusions: These results provide psychophysical evidence that visual perception of center-contextual stimuli is different between AUD and healthy control groups.

Effects of alcohol consumption on maxillofacial fractures in simple falls

Objectives

This study aimed to investigate the effects of alcohol consumption (AC) on maxillofacial fractures caused by falls on a level surface (simple falls).

Material and Methods

Patients with maxillofacial fractures caused by falls who visited the Oral and Maxillofacial Surgery Clinic from January 2006 to December 2016 were evaluated. Patients with simple falls were subdivided into those who fell with AC (Falls with AC) and those who fell without AC (Falls without AC).

Results

Of 180 patients with falls with maxillofacial fractures, 155 had simple falls, and 25 patients had falls from a height. Of the simple falls, 52 were Falls with AC, and 102 were Falls without AC. Falls with AC were significantly more frequent in males (p = .0005). The average number of fracture lines in the mandible was significantly higher in Falls with AC (2.13 ± 0.99 [mean ± SD]) than in Falls without AC (1.76 ± 0.91) (p = .011). The average Facial Injury Severity Scale was significantly higher in Falls with AC (3.08 ± 1.43) than in Falls without AC (2.43 ± 1.29) (p = .007).

Conclusions

Falls with AC were associated with more severe maxillofacial fractures than Falls without AC.

Ophthalmologic examinations under the acute influence of alcohol

Alcohol is the most widely used recreational drug in Western countries. It affects the psychophysical performance in different ways, e.g. by reducing cognitive functions, causing coordination disturbances or impairing vision. Visual impairments both concern oculomotor and visual sensory functions, such as decreased mesopic vision, decreased field of vision and an increase of saccadic eye movements. During cycling trials with alcoholised test persons, repeated measurements of (1.) the time needed to read a 50-word text, (2.) the time to perform a swing test by tenfold touching the moving fingertip of the examiner, and (3.) the amplitude of fusion were carried out. The results of these tests were further evaluated to test the hypothesis that impaired vision is significantly correlated to reduced cycling performances of alcoholised persons. In a second step, it was examined which test is most useful to identify alcohol intoxicated cyclists. The ophthalmologic examination results of the groups of best and worst cycling-performing test persons at blood alcohol levels between 0.10% and 0.15% were set into relation to the documented allocated demerits. Additionally, the individual results of these persons were compared to the state of soberness. The time needed to read a 50-word text significantly correlated with the cycling performance. As this is an easy and objective test, it might contribute to a synoptic evaluation of the psychophysical performance of a drunken cyclist.

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 ± 0.20 g/kg while performing perimetry and 0.84 ± 0.20 g/kg while performing anomaloscopy (BAC: 0.1 g/kg ≈ 0.01 g/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 0.8 g/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.

Psychophysical Evaluation of Visual Functions of Ex-Alcoholic Subjects After Prolonged Abstinence

Chronic alcohol abuse can lead to a brain damages, and the health status of alcoholics even after a long-term alcohol abstinence is a public health concern. The present study investigated the color vision and spatial luminance contrast sensitivity of a group of 17 ex-alcoholics (46.3 ± 6.7 years old) in long-term alcohol abstinence after having been previously under alcohol dependence for many years. We also investigated the association of impaired psychophysical performance in different tests we applied. The mean time of alcohol consumption was 16.9 ± 5.1 years and the mean abstinence period was 12.4 ± 8.5 years. Achromatic vision of all subjects was evaluated using spatial luminance contrast sensitivity function (CSF) test and color vision was evaluated using Mollon-Reffin color discrimination test (MR) and the Farnsworth-Munsell 100 hue arrangement test (FM100). Relative to controls, the spatial luminance contrast sensitivity was lower in 10/17 of the ex-alcoholic subjects. In the color vision tests, 11/16 ex-alcoholic subjects had impaired results compared to controls in the FM100 test and 13/14 subjects had color vision deficits measured in the MR test. Fourteen subjects performed all visual tests, three subjects had impaired results for all tests, seven subjects had impaired results in two tests, three subjects had visual deficit in one test, and one had normal results for all tests. The results showed the existence of functional deficits in achromatic and chromatic vision of subjects with history of chronic alcoholism after long abstinence. Most subjects had altered result in more than one test, especially in the color vision tests. The present investigation suggests that the damage in visual functions produced by abusive alcohol consumption is not reversed after long term alcohol abstinence.

The impact of age-related cataracts on colour perception, postoperative recovery and related spectra derived from test of hue perception

Background

Cataract patients were always excluded from studies on ageing of colour vision; thus, effect of age-related cataracts on deterioration of colour perception has not been analysed. In present study, impacts of age-related cataracts on colour discrimination, postoperative recovery and related spectra were investigated.

Methods

In this cohort study, thirty age-related cataract patients scheduled for binocular surgery and 30 elderly volunteers were enrolled. Colour discrimination under photopic (1000 lx) and mesopic (40 lx) conditions was evaluated with Farnsworth-Munsell 100-hue test. The total error score (TES) and partial error score (PES) were calculated.

Results

Preoperatively, the TES in the patient group was 129.7 ± 59.5 at 1000 lx and 194.6 ± 74.5 at 40 lx, exhibiting worse discrimination than the volunteer group (TES_1000lux = 71.5 ± 37.5 and TES_40lux = 113.1 ± 38.8, p ≤ 0.001). Inferior perception were detected in the yellow to green-yellow (Y-GY), green-yellow to green (GY-G), green to blue-green (G-BG) and blue-green to blue (BG-B) colour bands (p ≤ 0.003), corresponding to the 470 nm–580 nm range of the visible light spectrum. Under mesopic conditions, the impact expanded to all colour bands except for yellow-red to yellow (YR-Y). Postoperatively, the TES in the patient group were 80.4 ± 62.4 at 1000 lx and 112.0 ± 85.2 at 40 lx, which were lower than those of the preoperative phase (p ≤ 0.001) but similar to those of the volunteer group (p ≥ 0.505). Postoperative improvement occurred in the Y-GY, GY-G and G-BG colour bands (490 nm to 580 nm) at 1000 lx (p ≤ 0.001) and shifted to the Y-GY, GY-G, G-BG and BG-B colour bands (470 nm to 580 nm) at 40 lx (p ≤ 0.001). Deterioration of hue perception for decrement of illumination was detected in the red to yellow-red (R-YR), Y-GY, G-BG, BG-B, blue to purple-blue (B-PB) and red-purple to red (RP-R) colour bands (450 nm to 500 nm) in the volunteer group (p ≤ 0.002) and the R-YR, G-BG, BG-B, B-PB, PB-P and red-purple to red (RP-R) colour bands (from the short-wavelength end to 500 nm) in the patient group preoperatively (p ≤ 0.001).

Conclusions

Phacoemulsification could effectively rebuild colour perception in patients with age-related cataract. The postoperative benefits were most significant in colour bands corresponding with spectrum from 470 nm to 580 nm.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1057-6) contains supplementary material, which is available to authorized users.

Effects of acute alcohol ingestion on eye movements and cognition: A double-blind, placebo-controlled study

Alcohol is one of the most consumed psychoactive substances in the world, and the negative impact related to alcohol use has become a worldwide public health issue. Alcohol is able to affect diffusely several areas of the Central Nervous System, which could impair visual functions, including eye movements, and cognitive processes. The objective of the present study was to investigate the effects of moderate alcohol intake in eyes movements, as an indicator of cognitive processing underlying the visual search in a the Maze task. We investigated the concentration of 0.08% blood alcohol concentration (BAC), using an intra-subject, double-blind, and placebo-controlled experimental design with a sample size of 20 young adults (11 men and nine women). All volunteers participated in both conditions, i.e., alcohol (0.08%) and placebo (0.00%), in a counterbalanced order. We use the Tobii TX300 eye tracker to evaluate eye movements during completion of Visual Maze Test. The results showed significant differences in the following eye movement patterns: the first fixation latency, number and duration of fixations (mean and total), the number and duration of saccades (mean and total), and the total execution time in the test. In addition, we investigate the areas of interest (AOI), decision points in which the participant must decide which course to follow. We verified that the participants in the alcohol condition had a significantly greater number of fixations in both AOI, in comparison to the placebo condition. Overall, our findings confirm that moderate doses of alcohol can change the eye movements of young adults. These alterations may evidence the influence of alcohol in cognitive processes, such as flexibility, attention, and planning, which are required during resolution of Maze Task.

The Gold Standard Paradox in Digital Image Analysis: Manual Versus Automated Scoring as Ground Truth

CONTEXT

- Novel therapeutics often target complex cellular mechanisms. Increasingly, quantitative methods like digital tissue image analysis (tIA) are required to evaluate correspondingly complex biomarkers to elucidate subtle phenotypes that can inform treatment decisions with these targeted therapies. These tIA systems need a gold standard, or reference method, to establish analytical validity. Conventional, subjective histopathologic scores assigned by an experienced pathologist are the gold standard in anatomic pathology and are an attractive reference method. The pathologist's score can establish the ground truth to assess a tIA solution's analytical performance. The paradox of this validation strategy, however, is that tIA is often used to assist pathologists to score complex biomarkers because it is more objective and reproducible than manual evaluation alone by overcoming known biases in a human's visual evaluation of tissue, and because it can generate endpoints that cannot be generated by a human observer.

OBJECTIVE

- To discuss common visual and cognitive traps known in traditional pathology-based scoring paradigms that may impact characterization of tIA-assisted scoring accuracy, sensitivity, and specificity.

DATA SOURCES

- This manuscript reviews the current literature from the past decades available for traditional subjective pathology scoring paradigms and known cognitive and visual traps relevant to these scoring paradigms.

CONCLUSIONS

- Awareness of the gold standard paradox is necessary when using traditional pathologist scores to analytically validate a tIA tool because image analysis is used specifically to overcome known sources of bias in visual assessment of tissue sections.

Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin's Ellipses and the Farnsworth-Munsell 100-Hue Test

We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse’s long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u’ = 0.225, v’ = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies.