Introduction: Human vision allows for the perception of three primary colors: red, green, and blue. Any impairment in the perception of colors is referred to as color vision deficiency (CVD). CVD follows genetic inheritance. Genetic inheritance also extends to blood groups. While it is acknowledged that certain genetic diseases may exhibit a prevalence within specific blood groups, there is a dearth of such studies in CVD. Therefore, this study aims to ascertain the prevalence of CVD and explore any potential association with ABO blood groups, given their genetic inheritance. Materials and Methods: The research was conducted among young adults attending a tertiary care hospital in India. The Ishihara test plates were utilized to assess color vision, while the agglutination method was employed for ABO blood grouping. Results: Screening revealed that 640 (93.98%) participants had normal color vision, 40 (5.87%) exhibited CVD, and 1 (0.15%) subject was completely color blind, all of whom were male. Among those with CVD, blood group distribution included 7 (17.07%) individuals with blood group A, 21 (51.22%) with blood group B, 1 (2.44%) with blood group AB, and 11 (26.83%) with blood group O. Notably, the solitary color blind student belonged to blood group B (2.44%). Conclusion: Given the significance of color perception in their profession, this study enables young adults to identify and address any color vision deficiencies early in their careers. Additionally, it offers insights into the distribution of ABO blood groups among the study population. Future research with a larger sample size is recommended for more precise outcomes.
The atmosphere presents a vivid display of colors, from the azure hue of the sky to the crimson petals of roses and the verdant shades of grass. The human eye, endowed with the ability to perceive color in its entirety, distinguishes between various hues, intensities, and saturations, a privilege bestowed upon trichromatic individuals.. Trichromacy allows normal humans to discern three primary colors: red, green, and blue. Any deviation from this norm constitutes a condition known as color vision deficiency (CVD), with complete inability to perceive color termed color blindness. The genetic basis of red and green CVD lies on the q arm of the X chromosome, demonstrating X-linked recessive inheritance, predominantly affecting males while females act as carriers. Conversely, blue CVD follows autosomal transmission, residing on chromosome number 7, with a lower incidence compared to the former types. The perception of color relies on specialized cone cells within the retina, the lateral geniculate nucleus of the thalamus, and area V8 of the striate cortex [1,2]. The ability to discern color holds particular significance in certain professions, notably within young adults.
Karl Landsteiner's groundbreaking observation of blood variations among individuals led to the establishment of the modern ABO blood group classification system, a milestone recognized with the Nobel Prize in Physiology and Medicine
in 1930. This seminal discovery laid the groundwork for safe blood transfusion practices, marking a pivotal moment in medical history. Genetic inheritance governs the distribution of various blood groups, with certain diseases exhibiting differential prevalence among specific blood types. Notably, individuals with blood group A demonstrate a higher incidence of gastric carcinoma, while those with blood group O show elevated rates of duodenal ulcers. Furthermore, an increased propensity for myocardial infarction and diabetes mellitus is observed in individuals with blood group A [3,4].
Despite the recognized association between genetic diseases and specific blood groups, investigations in India, where consanguineous marriages are prevalent, have been lacking. Hence, this study aimed to ascertain the prevalence of CVD among young adults in India and explore any potential correlations with ABO blood groups. Additionally, the study sought to identify the types of CVD present among participants, facilitating early awareness and intervention.
A cross-sectional study was conducted involving young adults attending a tertiary care hospital in India. The participants, aged between 18 and 25 years. Out of the 789 who consented, 108 were excluded due to refractive errors, resulting in a final sample size of 681, comprising 445 males and 236 females. Written consent was obtained from each participant prior to the study.
Color vision assessment utilized Ishihara polychromatic plates featuring printed figures or numbers composed of colored spots against a background of similar-sized spots. Normal individuals correctly identify the figures or numbers, whereas those with CVD perceive different figures or numbers, or are unable to discern them altogether. Each eye underwent separate testing from a distance of 75 cm from the test chart, held perpendicular to the eye, under adequate room illumination for comfortable reading. Each plate was presented for three seconds. Participants identified with CVD underwent ABO blood grouping via the slide agglutination method in the hematology laboratory. Results were meticulously recorded and statistical analysis was performed using Microsoft Excel upon completion of the study.
Among the 681 students assessed, 640 (93.98%) demonstrated normal color vision, while 40 (5.87%) exhibited signs of CVD. Notably, one student (0.15%) exhibited complete color blindness (see Table 1). All identified color vision defects were of the red-green type, indicating a genetic transmission pattern. Additionally, all affected individuals were male.
Figure 1 illustrates the distribution of blood groups within the study population, with the majority falling under blood group B.
Analysis of blood group distribution among CVD subjects reveals a predominance of blood group B. Remarkably, the sole student with complete color blindness also belonged to blood group B (refer to Table 2).
0.15%, demonstrated complete color blindness. Notably, all affected individuals exhibited red-green type deficiencies, with no instances of blue CVD observed. Moreover, all identified cases were male subjects.
As documented in prior research, individuals with CVD face professional challenges. The prevalence of CVD varies across different racial groups and geographical regions. Vijayalaxmi et al. [5] reported a CVD prevalence of 2.1% in males and 0.2% in females among the South Indian Hindu population. Spalding [6] documented a prevalence of 8% in men and 0.4% in women among Caucasians. Niroula and Saha [7] found a prevalence of 3.8% among boys in western Nepal, with no cases observed in girls. In the USA, prevalence rates were reported as 12.8% among medical students [8] and 7.8% among dental students [9]. In the UK, histology students exhibited a prevalence of 8.7% [10]. Approximately 7% of males and 0.4% of females in the general American population were reported to have CVD [11]. In Faisalabad, Pakistan, prevalence rates were 2.4% in males and 4.48% in females [12]. A previous study in a medical college in coastal Odisha reported a prevalence of 8.91% in males and 0% in females [13]. Ebrahim [14] reported the percentage distribution of CVD among different blood groups in Kerala as 32 in group A, 27 in group B, 31 in group O, and 10 in group AB.
The distribution of CVD observed in the current study differs from previous findings, possibly due to the involvement of a distinct regional population compared to other studies, resulting in divergent outcomes. Further research involving a larger sample size, ideally sourced from the general population, is warranted to obtain more comprehensive insights.
CVD exhibits notable prevalence among young adults within India, with its distribution showing variance across distinct ABO blood groups. Early screening initiatives are imperative for individuals to ascertain their CVD status. Additionally, categorizing subjects based on their blood groups is recommended. Expanding the scope of screening to encompass larger cohorts, including those in schools and colleges, is advisable