Color Deficiency Research Articles

Frequency of Color Blindness in Driving License Candidates Presenting in Allied Hospital, Faisalabad

Background: Color vision is an integral part of visual functions. Defective color vision may leadto difficulties in daily activities and even choosing and continuing in a certain profession. Colorvision deficiency or blindness may be congenital or acquired due to retinal or optic nerve disorders Aim: To investigate the frequency of color blindness or weakness in driving license candidates presenting for medical exam, for the year 2019. Methodology: The study design was descriptive cross sectional and the sampling technique wasnon probability convenient sampling. The place of study was eye outdoor of Allied Hospital,Faisalabad. The sample size was 13,637 based on inclusion criteria. The subjects ranged in agefrom 18 years onwards to a maximum presentation of 76 years with mean age as 30.728 ±10.131.Both genders were included in the study. Visual acuity was tested on Snellen’s Chart andrefraction, if needed, was performed to obtain best corrected acuity. Results: The results of the study showed that most of the subjects had 6/6 vision as 96.6% in righteye and 96.5% in left eye, 6/9 as 2.8% and 2.9% and 6/12 as 0.3% and 0.4% respectively for rightand left eye. The frequency of normal color vision was 94%, 4.9% for red green deficiency and 1.1% for color blindness. Conclusion: A frequency of 4.9% and 1.1% for color deficiency and color blindness respectively, in drivers, indicates that color vision must be tested to avoid any possible accidents related todeficient color perception. Keywords: Driving license, colorblindness

Trichromatic Enhanced Dynamic Color Screening on the PDI Check Nintendo 3DS Game.

IntroductionClassification of color deficiency has required substantial time and expense with the static Farnsworth-Munsell and Innova Rabin tests. Therefore, dynamic color tests were developed for the Nintendo 3DS.MethodsFifteen color deficient patients and 17 age-matched normals performed Rabin color test in addition to PDI Check dynamic color games resembling Farnsworth-Munsell presentation (version 0.2.8) and 3-color iso-luminance gray (version 0.2.13).ResultsTests of red, green and blue cone-deficient with the v0.2.8 had sensitivity/specificity/PPV of 92%/86%/92% protanopes, 78%/90%/88% deutanopes and 87%/50%/93% tritanopes. Version 0.2.13 had sens/spec/PPV of 78%/83%/78% red-cone, 100%/85%/80% green cone and 67%/78%/33% blue cone. Corresponding IntraClass Correlation (ICC) utilizing v0.2.8 were red-cone 0.22 (−0.02–0.60), green-cone 0.34 (−0.10–0.67) and blue-cone 0.38 (0.12–0.75). ICC for v0.2.13 was higher with protanope 0.62 (−0.07–0.87), deuteranope 0.64 (−0.09–0.88) and tritanope 0.31 (−0.07–0.70). The PDI Check color game took 65 seconds compared to 197 seconds for Innova Rabin.ConclusionThe PDI Check color game quickly identifies patients with inherited color deficiencies.

Prevalence and predictors of colour vision defects among Egyptian university students.

Nowadays, widespread usage of colours increases the need for accurate estimation of colour vision defects and their effect on performing daily activities and study/work tasks. To determine the prevalence and predictors of colour vision defects among Assiut university students and to identify their relationship with self-reported visual function and perceived difficulties in performing daily activities. A cross-sectional study was conducted among 1426 students at Assiut University, Egypt. Data were collected by self-administered questionnaire consisting of: personal characteristics, prior awareness of colour vision defects, difficulties in daily colour vision activities, and visual function. Colour vision was assessed using Ishihara's test of colour deficiency. The prevalence of colour vision defects among students was 6.9% (red-green colour vision was 4.3% and total colour blindness was 2.6%). Students with colour vision defects had significantly higher odds ratios for difficulties in daily activities and study/work tasks related to colour perception. Students with colour vision defects had significantly lower mean values of general health, role difficulties, and colour vision scores compared to students with normal colour insight. Male sex and family history of colour vision defects were risk factors. A non-negligible percentage of Egyptian university students had colour vision defects, which had a negative impact on performing daily activities, executing study/work tasks, and choice of study/work specialties. Colour vision defects affected quality of life with regard to general health, role difficulties and colour vision. Male sex and family history of colour vision defects are nonmodifiable risk factors. This emphasizes the need for genetic counselling, especially in consanguineous marriage.

Vergleich zweier Screening-Verfahren zur Farbsinnprüfung: Ishihara-Tafeln vs. digitales Replikat

Comparison of two screening procedures for testing colour perception: Ishihara plates vs. digital replication Purpose: The study was designed to prove that the digitalized colour vision test integrated into the Optovist II is equivalent to the traditional Ishihara colour charts. Methods: Colour vision was tested with a sample size of 220 subjects (36 colour-deficient) and three different test methods. A new version of the Ishihara tablets was used under standard lighting conditions and at a distance of about 75 cm. The colour vision test (digitalized Ishihara plates) of a calibrated Optovist II (Vistec AG, Olching) and an HMC anomaloscope (Oculus Optikgeräte GmbH, Wetzlar) were also used. The first 17 plates of the Ishihara test were assessed in both the Ishihara colour vision test and the Optovist II, because the plates contain 18–24 lines that are not suitable for testing in the vision-testing device. Results: The test subject was classified as colour-deficient after two false readings of the pseudoisochromatic plates. The Ishihara plates provided the correct result in 200 subjects compared to the gold standard anomaloscope. In contrast, the Optovist II rated correctly in a total of 202 subjects. In the case of the Ishihara plates, 17 persons with normal colour vision were identified as having a colour deficiency, and three colour-deficient persons were classified as colour-competent. The Optovist II classified 16 colourcompetent persons as colour-deficient, and two colour-deficient persons as colour-competent. In addition, it was possible to test for equivalence using the McNemar test and to verify this. Conclusion: The two test methods should be considered equivalent. Both methods – Ishihara plates and their digital replica in the Optovist II – should be used exclusively as a screening method. A test with the anomaloscope should be performed for the final diagnosis. Keywords: Ishihara colour vision test – pseudoisochromatic panels – color vision – anomaloscope – digital colour vision test

Task-dependent contrast gain in anomalous trichromats

Anomalous trichromacy is a form of color vision deficiency characterized by the presence of three cone types, but with shifted spectral sensitivities for L or M cones, causing a red-green color deficiency. However, long-term adaptation to this impoverished opponent input may allow for a more normal color experience at the suprathreshold level (“compensation”). Recent experimental evidence points to the presence of compensation in some tasks. The current study used threshold detection, suprathreshold contrast matching, and a reaction-time task to compare contrast coding in normal and anomalous observers along the cardinal cone-opponent axes. Compared to color normals, anomals required more L-M contrast, but not S contrast, to detect stimuli and to match an achromatic reference stimulus. Reaction times were measured for several contrast levels along the two cone-opponent axes. Anomals had higher overall reaction times, but their reaction-time versus contrast functions could be matched to those of controls simply by scaling contrast by the detection thresholds. Anomalous participants were impaired relative to controls for L-M stimuli in all three tasks. However, the contrast losses were three times greater for thresholds and reaction times than for suprathreshold matches. These data provide evidence for compensation in anomalous trichromats, but highlight the role that the experimental task plays in revealing it.

Color perception and compensation in color deficiencies assessed with hue scaling

Anomalous trichromats have three classes of cone receptors but with smaller separation in the spectral sensitivities of their longer-wave (L or M) cones compared to normal trichromats. As a result, the differences in the responses of the longer-wave cones are smaller, resulting in a weaker input to opponent mechanisms that compare the LvsM responses. Despite this, previous studies have found that their color percepts are more similar to normal trichromats than the smaller LvsM differences predict, suggesting that post-receptoral processes might amplify their responses to compensate for the weaker opponent inputs. We evaluated the degree and form of compensation using a hue-scaling task, in which the appearance of different hues is described by the perceived proportions of red-green or blue-yellow primary colors. The scaling functions were modeled to estimate the relative salience of the red-green to blue-yellow components. The red-green amplitudes of the 10 anomalous observers were 1.5 times weaker than for a group of 26 normal controls. However, their relative sensitivity at threshold for detecting LvsM chromatic contrast was on average 6 times higher, consistent with a 4-fold gain in the suprathreshold hue-scaling responses. Within-observer variability in the settings was similar for the two groups, suggesting that the suprathreshold gain did not similarly amplify the noise, at least for the dimension of hue. While the compensation was pronounced it was nevertheless partial, and anomalous observers differed systematically from the controls in the shapes of the hue-scaling functions and the corresponding loci of their color categories. Factor analyses further revealed different patterns of individual differences between the groups. We discuss the implications of these results for understanding both the processes of compensation for a color deficiency and the limits of these processes.

Analysis of Color-Specific Visual Processing Speed Differences in Division 1 College Football Players

IntroductionThe University of Cincinnati has been doing NeuroVisual Training (NVT) as part of an injury prevention and performance enhancement program since 2010. We recently noticed that some athletes have substantial differences in visual reaction time based on color, specifically red versus green. We set out to assess if they may have had any color processing deficiencies.MethodsWe identified 4 out of 107 screened athletes with deficiencies in their ability to react to green compared to red. After identifying these color deficiencies, we developed a protocol to assess and manage the said deficiencies. The protocol included assessing for color blindness with the Ishihara plates, color Visual Evoked Potentials (cVEP), and color-based visual reaction times.ResultsNone of the individuals had color blindness based on the Ishihara plates. There were significant differences in visual reaction times for red and green with red being significantly slower. cVEP mean red P100 latency was 115.5 ± 3.2 ms versus 104.4 ± 1.3 ms for green, and mean voltage was 7.30 ± 1.4 µV versus 9.20 ± 1.4 µV for green.
 DiscussionNVT is becoming a mainstream means to improve performance and safety for athletes in competitive sports. It was interesting to note that high caliber athletes in a division 1 college football program were showing relatively slow visual reaction times. We were able to train them to a higher level of NVT proficiency once we included color-based tasks that best suited their ability to see and process quickly. People performing NVT on athletes may wish to be aware of and consider checking for color processing deficiencies such that one can train the athletes to the highest level possible.

Color perceptibility and validity of silicon carbide–based protective coatings for dental ceramics

Statement of problemA silicon carbide (SiC) protective coating has been developed for dental ceramics, but whether the coated ceramics can match the classical VITA shades is unclear. PurposeThe purpose of this observational in vitro study was to evaluate the color adaptability of SiC-coated dental ceramics by testing the hypotheses that SiC-coated disks can be fabricated to match standard tooth shades and have a perceptible color match rate of at least 50% for disks with a color difference (ΔE)<2.0. The effects of ΔE, shade hue, shade value, observer sex, years of experience, profession, and shade guide orientation on color perception were studied. Material and methodsSiC-coated disks were fabricated to color match (ΔEab<3.3) all 16 VITA classical shades. Uncoated disks of each VITA shade were used as the reference materials to determine whether the SiC-coated disks were color matched to the classical VITA shade guide. Three ΔE formulas (76, 94, and 2000) were applied and compared. Participants (N=120) with an average of 22 years of experience included dental school students, dental faculty members, and dental assistants. Pseudoisochromatic plate and the Farnsworth D-15 Panel test for assessing color deficiency and color blindness were administered. Participants then attempted to match SiC-coated disks to standard shade guides arranged by value or hue. All spectrophotometer readings and color matching were conducted in a light booth with standardized daylight illumination. Statistical analysis used the Fisher's exact test to determine factors associated with improved matching performance (α=.05). ResultsA significant difference in color match rate was found between disks with ΔE<2.0 (63.9%) and ΔE≥2.0 (41.7%) (P<.001). Arranging shade by value (72.2%) instead of hue (67.2%) produced better color matching (P<.001). Sex (P=.430), profession (P=.708), and years of experience (P=.902) had no significant influence on color matching. ConclusionsSiC-coated disks were successfully fabricated to match all VITA classical shades, and clinical visual color matching results confirmed that ΔE was a useful metric in optimizing color matching for the SiC-coated dental ceramics.

Examining Spatial Attributes for Color Deficient Observers

Color deficiency is a common affliction for males, with about 8% of the male population suffering from some form of – colloquial – color blindness. In common description, this is interpreted as the inability to perceive certain colors from a sensory standpoint. If that description is sufficiently complete, spatial attributes of the color signal should not influence the visual experience of a Color Deficient Observer (CDO).In this paper we describe the set-up and results of an experiment that is intended to vary the spatial attributes of a color deficiency test when shown to an observer. For this, we modified color vision charts to maintain their colorimetric attributes while varying spatial attributes and we measured color deficient observers with respect to their response accuracy and their response speed. We show results that indicate that there is a clear influence of color proximity in the responses.

Color Compensation in Anomalous Trichromats Assessed with fMRI

Anomalous trichromacy is a common form of congenital color deficiency resulting from a genetic alteration in the photopigments of the eye's light receptors. The changes reduce sensitivity to reddish and greenish hues, yet previous work suggests that these observers may experience the world to be more colorful than their altered receptor sensitivities would predict, potentially indicating an amplification of post-receptoral signals. However, past evidence suggesting such a gain adjustment rests on subjective measures of color appearance or salience. We directly tested for neural amplification by using fMRI to measure cortical responses in color-anomalous and normal control observers. Color contrast response functions were measured in two experiments with different tasks to control for attentional factors. Both experiments showed a predictable reduction in chromatic responses for anomalous trichromats in primary visual cortex. However, in later areas V2v and V3v, chromatic responses in the two groups were indistinguishable. Our results provide direct evidence for neural plasticity that compensates for the deficiency in the initial receptor color signals and suggest that the site of this compensation is in early visual cortex.

Color vision assessment‐1: Visual signals that affect the results of the Farnsworth D‐15 test

AbstractThe Farnsworth D‐15 test (D‐15) is commonly used to screen for moderate to severe congenital color vision deficiency. The aim of this study was to establish reliable D‐15 statistics for normal, deutan and protan subjects, and to investigate the different visual signals one can use to carry out the test, even in dichromats and rod monochromats. Six hundred and seventy‐four subjects were examined using the D‐15, the Colour Assessment and Diagnosis test and the Nagel anomaloscope. A rod monochromat and five dichromats were tested using the standard D‐15 protocol before the caps were separated into two groups and subjects were asked to repeat the task. D‐15 spectral radiance data, measured under D65 illumination, were used to estimate differences in photoreceptor excitations for each of the caps. When no crossings and up to two adjacent transpositions on the D‐15 results diagram are accepted as a pass, 100% of normal trichromats, 54% of deutans and 43% of protans pass the D‐15. A rod monochromat and two protanopes and deuteranopes were able to complete the D‐15 when the caps were separated into two groups, despite severe loss or even complete absence of color vision. When up to two adjacent transpositions are accepted 50% of color deficient subjects, some with severe red/green loss, pass the D‐15. While the D‐15 is normally used to screen for moderate to severe color deficiency, subjects with severe loss can still use combined, residual red/green, yellow/blue and luminance signals to pass.

Prevalence of Color Vision Deficiency among Dental Practitioners and its Effect on Shade Matching Ability

Objective: Shade selection is a crucial step in achieving aesthetically-pleasing restorations, and it is affected by the dentist’s ability to match the shade of the patient’s teeth. Color Deficiency Disease (CVD) has been thought to be a potential factor affecting color perception. The study aims to find the prevalence of CVD between dentists and dental students and to evaluate its effect on shade matching ability. Methods: A sample of 319 dentists and dental students in the College of Dentistry at Ajman University, Ajman, UAE was examined with the Ishihara test to find the prevalence of CVD. Then participants with CVD were tested for shade matching ability, and were compared to participants with normal color vision with the same gender and qualification level. They were asked to match 10 random composite samples with different shades to a custom shade guide made from the same composite material. A score was calculated, representing the number of correct answers they achieved. Results: The results showed that 8 out of 143 males (5.6%) had CVD, and 0 out of 176 females had CVD. There was no significant difference in the score of shade matching test between participants with CVD and participants with normal color vision (p=0.075). Conclusion: Males showed a higher prevalence of color vision deficiency than females. CVD had no significant effect on shade matching ability.

THE EFFECT OF EYE DOMINANCE IN COLOR PERCEPTION AMONG DENTAL STUDENTS WITH NORMAL COLOR VISION

Introduction: Various factors were reported to be responsible for influencing color perception during shade matching. These factors include lighting conditions and viewer's physiological variables. There is limited information regarding the effect of eye dominance in color perception in the dental literature. Objectives: To evaluate the effect of eye dominance on color perception among dental students in Alexandria University with normal color vision using Farnsworth- Munsell 100- hue test and the corresponding software. Materials and Methods: One hundred undergraduate dental students without congenital color deficiency were evaluated using Ishihara plates upon their voluntary participation. Out of these 100 participants, 43 were males and 57 were females. The dominant eye of each participant was determined using Miles test. Color perception evaluation was examined using Farnsworth – Munsell 100 hue test (FM 100 hue test). The data were tabulated and statistically analyzed using the Wilcoxon signed-rank test (α=0.05). Results: Statistical tests showed significant difference between the dominant eye and non-dominant eye in male participants (P=.031) and no significant difference between the dominant eye and non-dominant eye in female participants (P=.691). Conclusions: The dominance of the eye had a significant effect on the color perception in male participants. Keywords: Color matching, eye dominance, FM 100 hue test. Running title: The effect of eye dominance on color perception.

Analysis of Hue Circle Perception of Congenital Red-green Congenital Color Deficiencies Based on Color Vision Model

To investigate individual property of internal color representation of congenital red-green color-deficient observers (CDOs) and color-normal observers (CNOs) precisely, difference scaling experiment using pairs of primary colors was carried out for protans, deutans, and normal trichromats, and the results were analyzed using multi-dimensional Scaling (MDS). MDS configuration of CNOs showed circular shape similar to hue circle, whereas that of CNO showed large individual differences from circular to U- shape. Distortion index, DI, is proposed to express the shape variation of MDS configuration. All color chips were plotted in the color vision space, (L, r/g, y/b), and the MDS using a non-linear conversion from the distance in the color vision space to perceptual difference scaling was successful to obtain U-shape configuration that reflects internal color representation of CDOs.

Quantifying Color Vision Changes Associated With Cataracts Using Cone Contrast Thresholds.

PurposeTo evaluate effects of age and simulated and real cataractous changes on color vision as measured by the high-definition cone contrast test (CCT).MethodsTwenty-four healthy volunteers from two cohort studies performed CCT using best-corrected visual acuity, filters, mydriasis, and pinhole correction. Retrospective cross-sectional study of patients seen in eye clinics evaluated the relationship between age and color vision, and age and lens status in 355 eyes. Last, 25 subjects underwent CCT before and after cataract surgery.ResultsCCT scores were most reliable in the nonmydriatic condition without pinhole correction. Progressively dense brown filters produced small decreases in S-cone sensitivity. Linear regression analysis of phakic subjects showed a decline for all cone classes with age. Rate of decline was greater for S-cones (slope = −1.09; 95% confidence interval [CI], −1.30 to 0.86) than M-cones (slope = −0.80; 95% CI, −1.03 to −0.58) and L-cones (slope = −0.66; 95% CI, −0.88 to −0.44). CCT scores increased for S-cones but reduced for L- and M-cones in pseudophakic subjects compared with phakic patients. CCT scores after cataract surgery increased for S-cones, M-cones, and L-cones by 33.0 (95% CI, 8.6 to 57.4), 24.9 (95% CI, 3.8 to 46.0), and 22.0 (95% CI, −3.2 to 47.3), respectively.ConclusionsCCT assessment allows for clinically practical quantitation of color and contrast vision improvement after cataract surgery and aging patients who note poor vision despite good visual acuity.Translational RelevanceCCT testing, which quantifies hereditary and acquired color deficiency, can also quantify the degree of cataract severity and, combined with other parameters, can provide more precise guidance for cataract extraction to optimize patient care.

How colour‐deficient observers see things, or not.

AbstractColour deficiency or, colloquially, colour blindness, is common and has been observed and described in the scientific literature for ca. 200 years. In more recent times, algorithms have been developed that simulate the effect of colour deficiency to a colour‐normal observer. Sometimes these algorithms are used to indicate potential problems in the colour design, but often the implicit assumption is that a colour‐deficient observer actually sees things that way. But do they? This paper questions some of the underlying assumptions of the algorithms.

Color image evaluation of congenital red-green color deficient and normal color vision observers

How and to what extent the increase of Cab * affects on various subjective evaluations for congenital red-green color deficiency (CVD) and normal color vision (NCV) observers was investigated using scenery, food, and graph images. Results of "Pale vs Deep" evaluation indicate similar tendency for all color vision types in all test images, indicating that CVDs recognize the saturation change of images similar to NCVs using some kind of strategy. Individual differences of the CVDs in the results of other adjective pairs such as "Unnatural vs Natural" are generally larger than those of NCVs. Some color combinations in the graph images are indiscriminable for either protan or deutan, and thus are not recommended to be used.

Prevalence of Color Vision Deficiencies

Purpose. The study of color deficiencies prevalence in young people, students of higher educational university.Materials and methods. The study was carried for the half year — fall semester. A total of 1,609 students were examined, aged 17–21. There were 1191 boys and 418 girls. The survey was conducted to determine the health groups in physical training and in various sports sections. An ophthalmologic examination determined refractive disorders and other ocular pathology, which is important for determining health groups. Rabkin polychromatic tables and Neitz color vision test (Neitz Lab (UW Medicine) were used for determining of color deficiencies. The obtained results of these tests were compared in terms of the time spent on the test, the results of the test effectiveness, the determination of dissimulation, and the assessment of the shift in the color spectrum in individuals with impaired color perception.Results. A total of refractive disorders were detected in 856 students (53.2 %). The high degree of myopia was in 40. Disorders of color deficient were noted in 101 students (8.48 %) of 1191 male subjects when using the Neitz color test. Dichromatic eye changes were observed from 2.1 % students: protanopia and deiteranopia were in 0.67 % and 1.43 %. Most of all there were violations with the perception of shades of light brown and light green colors. A third of healthy students noted the impossibility of distinguishing light brown from light gray. This is regardless of the state of refraction. Simultaneous violations of the perception of shades of red, green, yellow and blue were observed in one subject, it was associated with congenital cataracts. In four young people, acquired eye diseases caused. In two girls, violations of the perception of a pastel shade of light green were noted, with one girl (0.24 %) having a violation in two eyes, and was presumably due to a gene anomaly. The second girl had one eye and was associated with partial atrophy of the optic nerve after the optic neuritis.Conclusions. Neitz color test expands the diagnostic possibilities, since in its design it has pastel shades of light green and light brown colors on a gray background, reduces the likelihood of dissimulation, reduces the time of the survey. Neitz color test allows to expand the possibilities for more accurate and differential diagnosis dichromatic and anormal trichromatic subjects and acquired color vision defects.

Frequency of Color Vision Deficiency among Saudi Dental Students: A Cross-Sectional Study.

Objective The current research was conducted to evaluate the frequency of color-vision deficiency among dental students of King Khalid University College of Dentistry, Saudi Arabia. Materials and Methods A cross-sectional study was performed among 203 dental students working as interns at male and female dental clinics of King Khalid University College of Dentistry (KKUCOD), Saudi Arabia. The Ishihara color-vision deficiency (CVD) test with 24 plates was used for diagnosis of the problem. Analysis of the data was done by performing Chi-square tests using SPSS software version 20. Results The frequency of total CVD was found to be 3.9%. While the association of gender with total CVD was observed to be statistically nonsignificant, a statistically significant relation was drawn with red-green color deficiency. Out of the total of 203 patients, 44 males were identified with red-green color deficiency, whereas only three females were found to have this condition, therefore revealing that CVD is more prevalent in males. Age was found to have a significant association with red-green color vision deficiency, protanopia, and total CVD. Conclusion A total of 20.19% male dental students had red-green color vision deficiency compared to 1.4% in female students. The dental students must be aware of their congenital color vision deficiency and its impact on their professional life. Screening of such dental students and professionals is quite important so that they can tackle the color vision problems well without having detrimental effect on their future dental practice.

Color Vision: Glasses Half Full

A new study finds that individuals with color deficiencies report long-term changes in their color vision after only a few days of wearing glasses that boost color contrasts, potentially because they learn to see or interpret color in new ways.