To determine the prevalence of refractive error (RE) as a cause in squinted in children in this aged (6-12 years) in Sulaimania city. The prevalence rate study among patient attending Shahed Dr. Aso eye hospital for the period from 1st October 2008 - 1st June 2009. A total of 116 children (6-12 years) attending squint department for about 8 months. The study included both sexes, were boys 55 and girls 61. Under went full ocular examination. We found that (72) patients (62.02%) had refractive error, include: 33 patients (45.9 %) = Hypermetropia (H); 22 patients (29.16%) = Myopia [M]; 18 patients (24.3%) Astigmatism (Ast.); 4 mixed; 6 H-Ast. and 8 M-Ast. In conclusions, the most prevalent cause of childhood squint at this aged (6-12 years) is refractive error while the other causes as a whole constitute only 1/3 of the causes, and most common refractive error is hypermetropia.
Refractive Error; Myopia; Hypermetropia; Astigmatism
Refractive Error (RE) is inability of eye to parallel light to focus on the retina i.e Second principal focus of eye does not fall on the retina (where the eye is at rest or accommodation).
1. Myopia (short sight) second principal focus lies in front of the retina: a. Axial myopia - abnormally long eye. b. Index myopia - (Refractive) e.g., keratoconus and nucleosclerosis.
2. Hypermetropia (long sight) the second principal focus lies behind retina: a. Axial hypermetropia. b. Refractive hypermetropia e.g., aphakia.
3. Astigmatism - refractive power of the astigmatic eye varies in different meridians: a. Regular astigmatism - principal meridian are at 90 to each other. b. Oblique astigmatism - principal meridian at 90 to each other, but not lies at or near 90 and 180. C. Irregular astigmatism - principal meridian are not at 90 to each other.
4. Anisometropia: refraction of the two eyes is different. Large degree of anisometropia is significant cause of amblyopia. Anisometropia of more than 1D in hypermetropia is enough to cause amblyopia because accommodation is binocular functions. Myopic with anisometropia is unlikely to develop amblyopia because both eyes have clear near vision .