CHAPTER 16

Decreased Vision in Infants and Children

When an infant has not developed good visual attention or the ability to fixate on and follow objects by 3–4 months of age, a number of causes must be considered. Ophthalmic (pregeniculate) causes of visual impairment include corneal and lenticular opacities, glaucoma, retinal anomalies or dystrophies, and optic nerve anomalies. Many of these are covered elsewhere in this volume. Other causes of reduced visual attention include delayed visual maturation and cerebral visual impairment (ie, postgeniculate visual impairment). These entities, which may be associated with other neurologic abnormalities, are discussed in this chapter.

Normal Visual Development

Visual development is a highly complex maturational process. Structural changes occur in both the eye and the central nervous system. Laboratory and clinical research has shown that normal vision develops as a result of both genetic coding and experience in a normal visual environment.

A blink reflex to bright light should be present within a few days of birth. The pupillary light reflex is usually present after 31 weeks’ gestation, but it can be difficult to evaluate in the early neonatal period because the pupils are miotic in the newborn.

At about 6–8 weeks of age, the healthy full-term infant should be able to make and maintain eye contact with other humans and react with facial expressions. Infants aged 2–3 months should be interested in bright objects. By age 3–4 months, smooth pursuit asymmetry should have resolved, the eyes should be orthotropic, and fix-and-follow visual responses to a small (2–4 inches in diameter) toy should be present. Premature infants can be expected to reach these landmarks later, but there is not an exact week-for-week correlation for the attainment of these milestones.

Disconjugate eye movements, skew deviation, and sunsetting (tonic downward deviation of both eyes) may be noted in healthy newborns but should not persist beyond 4 months of age. Signs of poor visual development include searching eye movements, lack of response to familiar faces and objects, and nystagmus. Staring at bright lights and forceful rubbing or poking of the eyes (oculodigital reflex) in an otherwise visually disinterested infant are other signs of poor vision and suggest an ocular cause for the deficiency.

Evaluation of the Infant With Decreased Vision

A careful history, beginning with a review of family history, is essential. The clinician should review details of the pregnancy, including maternal infection, maternal diabetes mellitus, radiation exposure, maternal drug or alcohol use, and trauma. Perinatal problems such as prematurity, intrauterine growth retardation, fetal distress, bradycardia, meconium staining, and oxygen deprivation are important. In addition, the clinician should inquire about the presence of systemic abnormalities or