Pediatric visual acuity examinations and vision care

Abstract

The visual system of newborn infants is not like that of adults. Both ocular and neural structures essential for vision will undergo anatomical and physiological changes as maturation process. The maturation of all visual systems occurs relatively rapidly in normal children. So, early examination of visual acuity is critical for normal visual funciton achievement. Visual acuity in preverbal children can be assessed using several techniques, such as fixation and following behavior under both monocular and binocular conditions, the optokinetic nystagmus technique, preferential looking, visual evoked potential, and recognition acuity using a vision chart. Most clinicians consider the standard technique of recognition acuity to be the gold standard for visual acuity assessments, 20/20 vision should be achieved by 7 years of age. Significant refractive error, a high degree of hyperopia, myopia, or astigmatism may result in not only blurred vision, but also strabismus and amblyopia. Therefore, early vision screening is very valuable. Subjective and objective refractive techniques are standard for detecting significant refractive errors in children and are available under either non-cycloplegic or cycloplegic conditions. Amblyopia is the most common cause of vision loss in children and young adults, defining as a reduction of best-corrected visual acuity due to the interruption of normal visual development during the so-called sensitive period. If the problem is not identified until the sensitive period is complete, the vision loss is permanent. Visual impairment in childhood affects all aspects of the child's development. Earlier treatment is associated with better outcomes. Of course, patient compliance and parental support are the most important factors contributing to treatment success.