Congenital Color Blindness in Young Turkish Men

Prevalence and genotypic frequency of color vision defects among primary schoolchildren in Adama Town, Eastern Ethiopia

Color vision deficiency is a common X-linked genetic disorder affecting the day-to-day lives of individuals, in which school-aged children's academic performance can be negatively affected. The aim of this study was to evaluate the prevalence and genotypic frequency of congenital color vision defects (CVD), among primary schoolchildren in Adama, Ethiopia. A school-based cross-sectional study design was used. Students were purposively selected based on their ethnicity but were randomly selected from their sections, resulting in a final sample size estimated at 846 schoolchildren who had received informed consent from their families. Data was gathered using the Ishihara color vision test, 38-plate edition. The result of the study revealed that the total prevalence of CVD was much higher (5.6%) among the male children than that of the females, which was only about 1.79%. The prevalence rates of CVD among the targeted ethnic groups were found to be the highest among Amhara (7.45%) > Oromo (5.00%) > Gurage (2.13%) children, respectively, in descending order. 62.76% of the study subjects were homozygous dominant (AA), followed by those with a heterozygous genotype (Aa) (32.51%), and the remaining 4.73% had recessive (aa) genes.

Prevalence of color vision deficiency among school-going boys in South India

Purpose:

Impact of color vision deficiency (CVD) on activities at school and productivity at work and consequential psychosocial difficulties has been reported. Although early detection and awareness help in overcoming these difficulties, screening for CVD is not a part of the school eye-screening initiatives in many countries. This study aimed at reporting the prevalence of CVD among school-going boys in Kanchipuram district, South India.

Methods:

The study was carried out as part of a school eye-screening program (SES) conducted in Kanchipuram district, Tamil Nadu, India for children between 6 and 17 years. The SES followed a three-phased protocol, which also included screening for CVD for all the boys between 11 and 17 years. The boys underwent CVD screening with Dalton's pseudo isochromatic plates (PIPs) followed by confirmation with Ishihara's PIP. The data were analyzed and the proportion of CVD in boys among different class grades, type of schools, location of schools, blocks of the district, and other clinical characteristics are presented.

Results:

Totally 250,052 children were screened in 1047 schools of which 74986 (60.61%) were boys between 11 and 17 years (mean age: 13.75 ± 1.91). The overall prevalence of CVD was found to be 2.76% (n = 2073; 95% confidence interval [CI]: 2.65–2.88). CVD was associated with urban locations (3.17% odds ratio [OR]: 1.90 95%CI: 1.69–2.13 P < 0.05) and public schooling (2.87%) (OR: 1.29 95%CI: 1.17–1.43 P < 0.05). Boys with CVD were less likely to have vision impairment (P = 0.002) and myopia (P < 0.001) as compared with boys with normal color vision. There was no significant difference in the proportion of other ocular conditions between children with and without CVD (P > 0.05).

Conclusion:

The study shows a significant proportion of CVD among boys in Kanchipuram district, India and its association with various demographic and clinical characteristics. Identification of CVD and counseling the stakeholders earlier through school children screening is crucial.

The prevalence of color vision deficiency in the northeast of Iran

PURPOSE

To determine the prevalence of color vision deficiency (CVD) in the northeast of Iran.

METHODS

This cross-sectional, population-based study was conducted in Mashhad, in the northeast of Iran. Multistage cluster sampling was used for selecting the participants. After preliminary screening, the subjects underwent a complete ophthalmic examination. The examination included the measurement of visual acuity, refraction, and slit-lamp biomicroscopy. The Farnsworth D-15 test was used to detect CVD. The color vision test was done with the best optical correction.

RESULTS

Of the 4453 invitees, 3132 participated in the study (response rate: 70.4%). The overall prevalence of CVD in this study was 13.93% [95% confidence interval (CI): 12.44-15.41]. The prevalence of CVD in males and females was 15.85% (95% CI: 13.26-18.44) and 12.96% (95% CI: 11.22-14.71), respectively. The most prevalent types of CVD were tritanopia (6.96%; 95% CI: 5.84-8.08), deuteranopia (3.92%; 95% CI: 3.14-4.70) and tritanomalous (2.21%; 95% CI: 1.55-2.86), respectively. According to the results of logistic regression, the odds of having protanopia were higher in females than males [Odds ratio (OR) = 4.80; 95% CI: 1.20-19.18]. The odds of having deuteranopia were lower in females than males (OR = 0.52; 95% CI: 0.35-0.76). The odds of having CVD were lower in 16-30 (OR = 0.52; 95% CI: 0.37-0.73) and higher in 46-60 (OR: 1.41; 95% CI: 1.01-1.97) year age groups compared to 7-15 year age group. The odds of having tritanopia in 16-30 and 46-60 year age groups was 0.56 (95% CI: 0.35-0.90) and 1.79 (95% CI: 1.19-2.67) compared to 7-15 year age groups, respectively.

CONCLUSION

The prevalence of CVD was high in this study, especially in males and people over 46 years of age. Planning for involvement of ocular disease control programs in health care systems can be helpful in the reduction of CVD and improving the quality of life in affected patients.

Prevalence of color vision deficiency among school children in Wolkite, Southern Ethiopia

Objective

Colour vision deficiency is the commonest disorders of vision and undiagnosed colour vision defect could pose a handicap to the performance of an affected student. The prevalence of colour blindness varies in different geographical area and ethnicity. Hence, a cross sectional study was conducted among school children in Gurage Zone, Southern Ethiopia from April 15 to June 20, 2018. Socio-demographic data was collected on a face to face interview using structured questionnaire. All study participants underwent color vision evaluation using Ishihara’s pseudo isochromatic test 38 plate editions. Data analysis was done using SPSS version 23.

Results

A total of 844 (471 boys and 373 girls) school children were screened for colour vision. The overall prevalence of colour vision deficiency was 4.1%, comprised of 3.6% in boys and 0.6% in girls. Out of 35 color blind subjects, 15 (42.9%) and 20 (57.1%) were the victims of protan and deutan defects respectively. Majority of the colour blind subjects were not aware of their colour vision status. Hence, the study concluded that the prevalence of colour vision deficiency in our study is significant and colour vision screening among school should be performed.

Frequency of color blindness in pre-employment screening in a tertiary health care center in Pakistan

Objective:

To describe the frequency of color vision deficiency among Pakistani adults presenting for pre-employment health screening in a tertiary care hospital.

Methods:

The cross-sectional study was carried out at the Aga Khan University Hospital, Karachi, and the data was collected for color vision deficiency, age, gender, and job applied for from pre-employment examination during 2013-2014. IBM SPSS 20 was used for statistical analysis.

Results:

Three thousand four hundred and thirty seven persons underwent pre-employment screening during 2013 and 2014; 1837 (53.44%) were males and 1600 (46.65%) females. The mean age was 29.01 (±6.53) years. A total of 0.9% (32/3437) persons had color vision deficiency with male being 1.4% and female 0.4%.

Conclusion:

Color vision deficiency was observed in 0.9% of candidates screened for pre-employment health check up in a tertiary care hospital. The color vision deficiency was predominantly present in male individuals.

Ability of Bottle Cap Color to Facilitate Accurate Patient-Physician Communication Regarding Medication Identity in Patients with Glaucoma

PURPOSE

To determine the accuracy of patient-physician communication regarding topical ophthalmic medication use based on bottle cap color, particularly among individuals who may have acquired color vision deficiency from glaucoma.

DESIGN

Cross-sectional, clinical study.

PARTICIPANTS

Patients aged ≥18 years with primary open-angle, primary angle-closure, pseudoexfoliation, or pigment dispersion glaucoma, bilateral visual acuity of ≥20/400, and no concurrent conditions that may affect color vision.

METHODS

A total of 100 patients provided color descriptions of 11 distinct medication bottle caps. Color descriptors were then presented to 3 physicians. Physicians matched each color descriptor to the medication they thought the descriptor was describing.

MAIN OUTCOME MEASURES

Frequency of patient-physician agreement, occurring when all 3 physicians accurately matched the color descriptor to the correct medication. Multivariate regression models evaluated whether patient-physician agreement decreased with degree of better-eye visual field (VF) damage, color descriptor heterogeneity, or color vision deficiency, as determined by the Hardy-Rand-Rittler (HRR) score and Lanthony D15 color confusion index (D15 CCI).

RESULTS

Subjects had a mean age of 69 (±11) years, with VF mean deviation of -4.7 (±6.0) and -10.9 (±8.4) decibels (dB) in the better- and worse-seeing eyes, respectively. Patients produced 102 unique color descriptors to describe the colors of the 11 bottle caps. Among individual patients, the mean number of medications demonstrating agreement was 6.1/11 (55.5%). Agreement was less than 15% for 4 medications (prednisolone acetate [generic], betaxolol HCl [Betoptic; Alcon Laboratories Inc., Fort Worth, TX], brinzolamide/brimonidine [Simbrinza; Alcon Laboratories Inc.], and latanoprost [Xalatan; Pfizer, Inc., New York, NY]). Lower HRR scores and higher D15 CCI (both indicating worse color vision) were associated with greater VF damage (P < 0.001). Extent of color vision deficiency and color descriptor heterogeneity significantly predicted agreement in multivariate models (odds of agreement = 0.90 per 1 point decrement in HRR score, P < 0.001; odds of agreement = 0.30 for medications exhibiting high heterogeneity [≥11 descriptors], P = 0.007).

CONCLUSIONS

Physician understanding of patient medication use based solely on bottle cap color is frequently incorrect, particularly in patients with glaucoma who may have color vision deficiency. Errors based on communication using bottle cap color alone may be common and could lead to confusion and harm.

Prevalence and gene frequency of color vision impairments among children of six populations from North Indian region

X-linked red-green color blindness is the most widespread form of vision impairment. The study aimed to determine the prevalence and gene frequencies of red-green color vision impairments among children of six different human populations of Jammu province. A total of 1028 healthy subjects (6-15 years of age) were selected from five Muslim populations and the color vision impairments were determined using the Ishihara's test of color deficiency. The gene frequency was calculated using Hardy-Weinberg equilibrium method. The prevalence of color vision deficiency (CVD) ranged from 5.26% to 11.36% among males and 0.00%-3.03% among females of six different populations. The gender based differences in the frequency of CVD was found to be statistically significant (p < 0.0001), with a higher prevalence among male (7.52%) as compared to female (0.83%) children. We observed high frequency of deutan as compared to protan defects. The incidences of deuteranomaly (5.68%) and deuteranopia (2.27%) were higher among male children of Syed population while the frequencies of protanomaly (1.94%), protanopia (1.28%) and achromacy (2.27%) were the highest among male subjects of Khan, Malik and Syed populations, respectively. The allele and genotype frequencies showed cogent differences among six populations. The population based assessment of CVDs help patients to follow adaptive strategies that could minimize the risks of the disease.

Color vision deficiency in Zahedan, Iran: lower than expected

PURPOSE

To estimate the prevalence of congenital red-green color vision defects in the elementary school students of Zahedan in 2012.

METHODS

In this cross-sectional study, 1000 students with a mean (±SD) age of 9.0 (±1.4) years were selected randomly from a large primary school population. Color vision was evaluated using the Ishihara pseudoisochromatic color plates (38-plate edition). A daylight fluorescent tube was used as an illuminant C equivalent (i.e., 860 lux, color rendering index greater than 92, and color temperature = 6500 K). Having more than three misreadings on the test was considered a failing criterion. Data were analyzed in SPSS version 17 software using χ2 tests.

RESULTS

Nine students (0.9%) made more than three errors on the Ishihara test. Based on this criterion, the prevalence of red-green color vision deficiency in girls and boys was 0.2 and 1.6% (p = 0.02), respectively.

CONCLUSIONS

The prevalence of red-green color vision deficiency was found to be significantly lower in Zahedan than comparable reports in the literature.

Color vision deficiency in preschool children: the multi-ethnic pediatric eye disease study

PURPOSE

To determine the sex- and ethnicity-specific prevalence of color vision deficiency (CVD) in black, Asian, Hispanic, and non-Hispanic white preschool children.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

The Multi-Ethnic Pediatric Eye Disease Study is a population-based evaluation of the prevalence of vision disorders in children in Southern California. A total of 5960 subjects 30 to 72 months of age were recruited for the study, of whom 4177 were able to complete color vision testing (1265 black, 812 Asian, 1280 Hispanic, and 820 non-Hispanic white).

METHODS

Color vision testing was performed using Color Vision Testing Made Easy color plates (Home Vision Care, Gulf Breeze, FL), and diagnostic confirmatory testing was performed using the Waggoner HRR Diagnostic Test color plates (Home Vision Care).

MAIN OUTCOME MEASURES

Testability of color vision in preschool children between 30 and 72 months of age and prevalence of CVD stratified by age, sex, and ethnicity.

RESULTS

Testability was 17% in children younger than 37 months of age, increasing to 57% in children 37 to 48 months of age, 89% in children 49 to 60 months of age, and 98% in children 61 to 72 months of age. The prevalence of CVD among boys was 1.4% for black, 3.1% for Asian, 2.6% for Hispanic, and 5.6% for non-Hispanic white children; the prevalence in girls was 0.0% to 0.5% for all ethnicities. The ethnic difference in CVD was statistically significant between black and non-Hispanic white children (P = 0.0003) and between Hispanic and non-Hispanic white children (P = 0.02). In boys, most CVD cases were either deutan (51%) or protan (34%); 32% were classified as mild, 15% as moderate, and 41% as severe.

CONCLUSIONS

Testability for CVD in preschool children is high by 4 years of age. The prevalence of CVD in preschool boys varies by ethnicity, with the highest prevalence in non-Hispanic white and lowest in black children.

Worldwide prevalence of red-green color deficiency

Literature that describes the prevalence of inherited red-green color deficiency in different populations is reviewed. Large random population surveys show that the prevalence of deficiency in European Caucasians is about 8% in men and about 0.4% in women and between 4% and 6.5% in men of Chinese and Japanese ethnicity. However, the male: female prevalence ratio is markedly different in Europeans and Asians. Recent surveys suggest that the prevalence is rising in men of African ethnicity and in geographic areas that have been settled by incoming migrants. It is proposed that founder events and genetic drift, rather than natural selection, are the cause of these differences.

Prevalence of refraction errors and color blindness in heavy vehicle drivers

AIM

To investigate the frequency of eye disorders in heavy vehicle drivers.

METHODS

A cross-sectional type study was conducted between November 2004 and September 2006 in 200 driver and 200 non-driver persons. A complete ophthalmologic examination was performed, including visual acuity, and dilated examination of the posterior segment. We used the auto refractometer for determining refractive errors.

RESULTS

According to eye examination results, the prevalence of the refractive error was 21.5% and 31.3% in study and control groups respectively (P<0.05). The most common type of refraction error in the study group was myopic astigmatism (8.3%) while in the control group simple myopia (12.8%). Prevalence of dyschromatopsia in the rivers, control group and total group was 2.2%, 2.8% and 2.6% respectively.

CONCLUSION

A considerably high number of drivers are in lack of optimal visual acuity. Refraction errors in drivers may impair the traffic security.

Ocular findings among young men: a 12-year prevalence study of military service in Poland

PURPOSE

To determine the prevalence of ocular diseases among young men and to assess the main ocular causes reflecting discharge from military service in Poland.

METHODS

A retrospective review of the medical records of 105 017 men undergoing a preliminary examination for military service during the period 1993-2004. Sample size for the study was calculated with 99% confidence within an error margin of 5%. All of the study participants were White men of European origin, most of whom live or lived in Poland. Data regarding the vision status were assessed in 1938 eyes of 969 participants. Two groups were distinguished based on the age of the participants: group I aged 18-24 years, and group II aged 25-34 years.

RESULTS

Presented visual impairment [visual acuity (VA)<20/40)] followed by colour vision defects were the most common ocular disorders, accounting for 13.2%. There were statistically significant differences in uncorrected VA as well as in the rates of particular refractive errors in between the age groups (p<0.05). The prevalence of glaucoma and ocular hypertension was significantly higher in older participants. Six hundred and sixty-seven (68.8%) participants examined medically in the study period were accepted for military service. However, 302 (31.2%) failed their examination and were temporarily or permanently discharged from duty. Fifty-two of them (17.2%) were discharged because of various ocular disorders. The most common causes were high refractive errors, which accounted for 38.5% of all the ocular discharges, followed by chronic and recurrent diseases of the posterior segment of the eye, which accounted for 19.2%.

CONCLUSION

The prevalence of ocular disorders among young men in an unselected military population was closer to the results obtained in other population-based studies comprising both men and women in the same age group. High refractive errors followed by chronic and recurrent diseases of the posterior segment of the eye are important causes of medical discharges from military service in Poland.

Shade matching performance of normal and color vision-deficient dental professionals with standard daylight and tungsten illuminants

STATEMENT OF PROBLEM

The lighting conditions of the environment and visual deficiencies such as red-green color vision deficiency affect the clinical shade matching performance of dental professionals.

PURPOSE

The purpose of this study was to evaluate the shade matching performance of normal and color vision-deficient dental professionals with standard daylight and tungsten illuminants.

MATERIAL AND METHODS

Two sets of porcelain disc replicas of 16 shade guide tabs (VITA Lumin) were manufactured to exact L*a*b* values by using a colorimeter. Then these twin porcelain discs (13 mm x 2.4 mm) were mixed up and placed into a color-matching cabinet that standardized the lighting conditions for the observation tests. Normal and red-green color vision-deficient dental professionals were asked to match the 32 porcelain discs using standard artificial daylight D65 (high color temperature) and tungsten filament lamp light (T) (low color temperature) illuminants. The results were analyzed by repeated-measures ANOVA and paired and independent samples t tests for the differences between dental professionals and differences between the illuminants (alpha=.05).

RESULTS

Regarding the sum of the correct shade match scores of all observations with both illuminants, the difference between normal vision and red-green color vision-deficient dental professional groups was not statistically significant (F=4.132; P=.054). However, the correct shade match scores of each group were significantly different for each illuminant (P<.005). The correct shade matching scores of normal color vision dental professionals were significantly higher with D65 illuminant (t=7.004; P<.001). Color matching scores of red-green color vision-deficient dental professionals (approximately 5.7 more pairs than with D65) were significantly higher with T illuminant (t=5.977; P<.001). CONCLUSIONS.: Within the limitations of this study, the shade matching performance of dental professionals was affected by color vision deficiency and the color temperature of the illuminant. The color vision-deficient group was notably unsuccessful with the D65 illuminant in shade matching. In contrast, there was a significant increase in the shade matching performance of the color vision-deficient group with T illuminant. The lower color temperature illuminant dramatically decreased the normal color vision groups' correct shade matching score.

Retinal nerve fiber layer thickness in congenital color vision deficiency

PURPOSE

To evaluate the thickness of the retinal nerve fiber layer (RNFL) in subjects with congenital red-green color vision deficiency (CVD).

METHODS

This study included 20 healthy subjects with congenital red-green CVD and 22 healthy subjects with normal color vision. After Ishihara test and examinations visual field by automated perimetry, all individuals underwent scanning laser polarimetry to measure the thickness of the RNFL.

RESULTS

All scanning laser polarimetry parameters related to RNFL thickness were found to be similar in subjects with congenital CVD and normal color vision (p>0.05).

CONCLUSIONS

This is the first report suggesting normal thickness of the RNFL in subjects with congenital red-green CVD.