Wube, Tilaye (PhD)Shiferaw, Solomon2022-01-042023-11-092022-01-042023-11-092021-12-30http://etd.aau.edu.et/handle/123456789/29467Acuity of vision is the ability of the eye to determine the precise shape and details of an object. Normal vision refers to a state in which parallel light rays entering the eye form images on the retina when the eye is in a completely unregulated state. Refractive errors affect a large proportion of the population worldwide, irrespective of age, sex and ethnic group. They can easily be diagnosed, measured and corrected with spectacles or other refractive corrections to attain normal vision. The eye is very important to perceive colors using photo receptors found in the retina. Color deficiency describes the inability or decreased ability to identify colors or perceive color differences under normal lighting conditions. The cause of color vision deficiency can be acquired or inherited. Certain diseases, drugs and chemicals may cause color blindness. It can also be caused by accidents or trauma which produces swelling of the brain in the occipital lobe. Most of the inherited color vision deficiencies are due to the inheritance of mutated gene on the X-chromosome. The purpose of this study was to assess the prevalence of visual deficiency and color blindness among high school students. Regular students of 824 Menelik II Preparatory School participated in the study. Visual acuity was tested by using Snellen chart and that of color vision test by using Ishihara 24 plates. The result shows that 92 percent of the students had a normal visual acuity. On the other hand, a small percentage i.e. nearly eight percent had mild visual deficiency where they were unable to discriminate all the letters in Snellens chart. More males showed the mild visual deficiency compared to females (39 vs 28), However, this difference was not statistically significant (p=0.179). Regarding color vision, 32(3.88%) males and 29(3.51%) females were found to be color deficient. The difference between male and female students with color deficiency was not statistically significant (p=0.701). Of the total subjects found to have color deficiency, 24(2.91%) males and 18(2.18%) females were deutans; whereas, 8(0.97%) and 11(1.33%) males and females were protons respectively. These data imply that 42(5.09%) of the subjects were deutans and 19(2.30%) were protans. Out of the 61 students who showed color vision deficiency 69% had the Deutran type while 31% had the Protan type. None of the students were Protanopan. Deutranopia was more common among males while the reverse was true for protan. The overall difference between deutans and protons was statistically significant (p=0.003).Therefore, the result of the present study showed that visual deficiency should be given importance.enColor BlindnessVisual AcuityVisual DeficiencySchool ChildrenThesis