Guidelines for prescribing optical correction in children.

As the eye grows, the axial length increases while the cornea and lens flatten. High refractive errors which are common in the neonatal period, reduce rapidly during the first year of life through the process called emmetropization. The possibility that long-term full- time glasses wear may impede emmetropization must be considered. Hyperopia greater than 5.00 diopters (D) in young children is associated with an increased risk of amblyopia and strabismus, therefore optical correction should be prescribed. When hyperopia is associated with esotropia, full correction of the cycloplegic refractive error should be prescribed. Myopia greater than 8.00 D and astigmatism greater than 2.50 D are common causes of isometropic amblyopia. Patients with hyperopic anisometropia with as little as l D difference between the eyes may develop amblyopia while the difference should reach 3-4 D for myopic anisometropia to develop amblyopia. Full cycloplegic refractive difference between two eyes should be given to the anisometropic child in spite of age, strabismus and degree of anisometropia. Myopia control is the attempt to slow the rate of progression of myopia such as cycloplegic agents, plus lenses at near, and rigid contact lenses.