Abstract
Abstract: :
Purpose: To evaluate the overall prevalence of visual acuity (VA) deficiencies in a pre–school screening in the county of Parma, Northern Italy. Methods: 149 children out of a population aged 38 to 46 months attending 10 kindergarten classes were enrolled in a screening program in order to identify VA deficiencies . VA assessment was performed using the LEA Chart at 3 meters distance. After the screening test every child underwent a complete ophthalmic examination, including cycloplegic refraction , fundus examination and cover test. VA deficiency was defined as VA less than 0.1 Log MAR confirmed by any abnormal finding in the ocular examination. Abnormalities considered as significant to determine VA deficiency were: 1. potentially amblyogenic anisometropia or strabismus; 2. any media opacities; 3. uni– or bilateral refractive error that would not cause amblyopia but that would need spectacle correction to improve quality of vision (i.e.:unilateral myopia > 1,5 diopters (D), bilateral myopia >/= 3D, bilateral hyperopia > than 3D, uni– or bilateral astigmatism >/= than 1 D); 4. retinal or optic nerve abnormality. Results:22 children were found affected by visual acuity deficiency. 3 of them were amblyopic (1 had unilateral hyperopia, 2 had bilateral astigmatism). Among the non–amblyopic children, 8 had unilateral astigmatism , 4 had bilateral astigmatism, 1 had unilateral hyperopia, 4 had bilateral hyperopia , 1 had bilateral hyperopia and strabismus and 1 had bilateral hyperopia and astigmatism. The calculated overall prevalence of any kind of visual acuity deficiency was 14.76% (C.I. 95%: 10%–21.3%). Conclusions: To our knowledge this is the first attempt to estimate the prevalence of VA deficiency of any grade in a pre–school population. The observed VA deficiency prevalence doesn’t take into account normal children with a "false positive" VA test (those children, re–tested in a few weeks, presented with normal VA on the second test), so it evaluates the number of children with true eye abnormality and/or refractive error. Our results indicate that screening programs performed in this age range may offer the opportunity not only to treat amblyopia but also to achieve the best potential visual acuity in non–amblyopic children.
Keywords: amblyopia • clinical (human) or epidemiologic studies: prevalence/incidence • visual acuity