Red-Green Color Vision Deficiency and Lack of Awareness among Rural School Students in India

Color vision deficiency (CVD) occurs when there is an error in the development of one or more types of retinal cone cells that receive color in light and transmit that information to the optic nerve (1). Among them, red-green CVD shows the highest prevalence (2). Red-Green CVD is divisible into severe or dichromatic forms [protanopia and deu-teranopia] and milder or anomalous trichromatic forms [protanomaly and deuteranomaly] (2, 3). Color is used as a systematic identifier in some learning systems in school. In addition, students start growing their interest in career selection at school level. It is regrettable that a large section of school students are not aware of their color vision status (4). CVD does not cause complete blindness and there is no available therapeutics that can treat CVD. However, employment in certain professions like working as pilot, loco driver, traffic police, defense servant and a few others require a normal color vision as their eligibility criterion and hence color blind persons are likely to be rejected from such professions. The present study was to determine the occurrence of CVD among students of Nalgoradham Baikun-tha Vidyapith, a village based high school of West Bengal, India as well as to explore the awareness of CVD among them and their family members. The study was approved by the institutional Managing Committee and the Principal of Nalgoradham Bai-kuntha Vidyapith. Overall, 738 students (345 males and 393 females) were subjected to 38 plate edition of Ishihara Test Plates (ITP) following the recommendation of Ishihara (5). The data obtained was analyzed statistically with student's t test using Epi Info (SPSS, Chicago, IL, USA) software and a P value less 0.05 was considered significant. Of the 738 students, 30 were affected (4.06%). The total number of affected males was 22 (6.37%) while affected females were 08 (2.03%). Out of 345 males, 10 (2.9%) were dichromatic (prota-nopic and/or deuteranopic). Similarly, out of 393 females, 3 (0.76%) were dichromatic. Six males (1.74%) and 1 female (0.25%) were protanopic while 4 males (1.16%) and 2 females (0.51%) were deuteranopic. Among the 738 students, only 2 males were both protanopic and deuteranopic. To avoid statistical bias, their data were included separately as protan as well as deutan. Additionally, we found that 17 (2.30%) students were anomalous trichromates (protanomalic and/or deuter-anomalic). Among 345 males, 12 (3.47%) students exhibited anomalous trichromacy of which 3 (0.87%) were protanomalic and 9 (2.61%) were deuteranomalic. …