If history and examination are otherwise normal, wait 2 months to refer.

If nystagmus or abnormal pupils are present, refer.

What Shouldn’t Be Missed

Septo-optic dysplasia should not be missed owing to the potential for pituitary dysfunction.

During the first 1 to 2 months of life, visual behavior in infants varies widely. Some babies fixate immediately after birth, whereas others take several weeks to begin tracking. At the 1-month well-child examination parents may specifically express concern if their baby is not fixating. Others may not be aware of any problems, but you will notice poor tracking on your examination. If everything else is normal (see the following sections), an appropriate plan is to wait until 2 months of age to see whether the tracking spontaneously improves, which will occur in most cases.

By 2 months of age, the absence of fixation does not necessarily mean that there is an underlying problem, but the level of concern is raised. Referral to a pediatric ophthalmologist is appropriate at this time. Items from the history and ocular examination can help determine what additional steps are indicated.

There are 3 main categories for infants who are not fixating by 2 months of age:

• 1. Infants who are otherwise normal, and have no other ocular abnormalities.
  
  
  
  • These children most commonly have delayed visual maturation (DVM) (also known as cortical inattention). The eyes themselves are fine in these babies, but the cortical connections that allow the brain to perceive images and make appropriate behavioral responses are underdeveloped. Most of these children will improve by 4 to 6 months of age, and further workup by the ophthalmologist is not indicated early in life, unless other abnormalities are found on the eye examination. If the infants continue to demonstrate poor fixation when they return for their follow-up examination with the ophthalmologist, additional testing will be necessary.
  
  
• 2. History of serious systemic disease.
  
  
  
  • Any significant illness, particularly one that affects the central nervous system, may cause a delay in visual tracking in infants (Table 3–1). Common diseases include prematurity (especially less than 30 weeks gestation), perinatal hypoxia, hydrocephalus, and seizure disorders. Children with other severe systemic diseases, such as cardiac or pulmonary disorders, may also not track well initially.
    
  • Children with developmental delay, regardless of the etiology, also frequently take longer than usual to begin tracking normally. However, because of the wide variability in normal development in the first few months of life, and because isolated poor visual tracking may be confused with general developmental delay, it may be difficult to determine whether children are delayed until they are several months old.
    
  • Children with these other medical problems may have DVM, but it frequently takes more time to improve than similarly affected normal infants described above. If the vision does not improve, cortical visual impairment (CVI) may be present. Unlike DVM, in which normal cortical connections eventually form, children with CVI are assumed to have structural abnormalities in the visual processing portions of the brain. Although the vision in affected patients usually improves with age, it may not reach normal levels.
  
  
• 3. Children with primary vision disorders.
  
  
  
  • If an infant has an ocular problem that seriously affects vision, a pattern of abnormalities typically develops by 2 to 3 months of age. Depending on the severity of the underlying disorder, the infants may have no or minimal reactions to light, even when very bright lights are shined directly into the eyes. The absence of pupil reactions to light is another manifestation of severe vision loss. Although this is an excellent objective measure of visual function, the pupil reaction may be difficult to assess in a newborn. If infants do not have normal vision, nystagmus usually develops around 2 months of age. The combination of these 3 findings (abnormal pupil reactions, no or minimal fixation, and nystagmus) suggests a serious underlying problem, and further investigations are warranted. The list of potential etiologies is very long, including congenital retinal dystrophies (e.g., Leber’s congenital amaurosis), cataracts, optic nerve hypoplasia, severe retinopathy of prematurity, and multiple other disorders.