الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Ametropia is a condition of refractive error it occurs when the shape, dimensions and components of the human eye prevent parallel light rays from focusing directly on the retina. The axial length of the eyeball, changes in the shape and curvature of the cornea, and or the crystalline lens are the common causes for refractive errors. The most common types of refractive errors are myopia and hyperopia, which occurs respectively when parallel rays of light coming from infinity are focused either in front or behind the retina after passing through the dioptric power of the eye when the accommodation is at rest. However, in astigmatism the parallel rays of light focused in a circle in contrast to point in astigmatic eye, hence this error gives blurry and stretched images.
Refractive errors remain one of the most common causes of visual impairment. In developing countries mostly 500 million of population, including children do not have access to undergo an eye examination. Many of them are not aware that their compromised vision could be cured or they cannot afford the appliance needed for correction. The most common problems among school children is childhood visual impairment due to refractive errors. Two thirds of visually impaired children live in the developing countries of the world and approximately 500,000 children become amblyope each year. WHO and a coalition of nongovernment organizations launched a global initiative, Vision 2020: the right to sight which aims correction of refractive errors in childhood.
Nowadays, uncorrected refractive error is the second leading cause of treatable blindness and the primary cause of visual disability among children in the world. Most of the children with uncorrected refractive error are asymptomatic and hence children without vision correcting glasses is of meticulous concern in latest studies.
Ocular screening programs in school-aged children are valuable and crucial for children as screening programs helps in early detection and timely interventions. It also has constructive effects on the psychosocial development of children. School screening programs enable detection of amblyopia and its risk factors such as strabismus, refractive errors particularly anisometropia, and media opacities earlier hence, It facilitates the prophylaxis and treatment of amblyopia. Diagnosis and treatment of amblyopia at a younger age may result in an enhanced and more stable concluding visual acuity in association with shorter treatment periods, rapid improvement of visual acuity, and better compliance in general with treatment regimens.