2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Chapter 4: Clinical Refraction
Prescribing for Children
The correction of ametropia in children presents several special and challenging problems. In adults, the correction of refractive errors has 1 measurable endpoint: the best-corrected visual acuity. Prescribing visual correction for children often has 2 goals: providing a focused retinal image and achieving the optimal balance between accommodation and convergence.
In some young patients, subjective refraction may be impossible or inappropriate, often because of the child’s inability to cooperate with subjective refraction techniques. In addition, the optimal refraction in infants or small children (particularly those with esotropia) requires the paralysis of accommodation with complete cycloplegia. In such cases, objective techniques such as retinoscopy are the best way to determine the refractive correction. Moreover, the presence of strabismus may require modification of the normal prescribing guidelines.
There are 2 types of childhood myopia: congenital (usually high) myopia and developmental myopia, which usually manifests itself between the ages of 7 and 10 years. Developmental myopia is less severe and easier to manage because the patients are older and refraction is less difficult. However, both forms of myopia are progressive; frequent refractions (every 6–12 months) and periodic prescription changes are necessary. The following are general guidelines for correction of significant childhood myopia:
Cycloplegic refractions are mandatory. In infants, children with esotropia, and children with very high myopia (>10.00 D), atropine refraction may be necessary if tropicamide or cyclopentolate fails to paralyze accommodation in the office.
In general, the full refractive error, including cylinder, should be corrected. Young children tolerate cylinder well.
Some ophthalmologists undercorrect myopia, and others use bifocal lenses with or without atropine, based on the theory that accommodation hastens or increases the development of myopia. This topic remains controversial among ophthalmologists. (See BCSC Section 6, Pediatric Ophthalmology and Strabismus.)
Intentional undercorrection of a child’s myopic esotropia to decrease the angle of deviation is rarely tolerated.
Intentional overcorrection of a myopic error (or undercorrection of a hyperopic error) may help control intermittent exodeviations. However, such overcorrection can cause additional accommodative stress.
Parents should be educated about the natural progression of myopia and the need for frequent refractions and possible prescription changes.
In older children, contact lenses may be desirable to avoid the problem of image minification that arises with high-minus lenses.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.