The infant's first eye examination is performed sometime after birth and prior to discharge home. The extent of the examination should be appropriate to the infant's condition. This initial selective screening examination assesses structural development of the eyes and the relationship of the eyes to the overall facies. In addition, reactivity of the pupils and the red reflex are assessed. The eye examination also provides a good opportunity to observe an infant's resting state and his or her ability to transition from one state to another. Observations that give information about the infant's general well-being and maturity include apparent awareness and visual interest in the surroundings as opposed to abnormal staring or absent visual fixation. In otherwise healthy infants, assessment of visual acuity is delayed until early childhood when cooperation with the eye examination can be expected. Normal findings that resolve include edema, eversion, bruising, hemorrhage, and nevus simplex. (See also Chapter 6.)
The American Academy of Pediatrics (AAP) recommends an age-appropriate assessment in the newborn period: ocular history, vision assessment (ability to fix and follow objects after 3 months of age), external inspection of the eyes and lids (conjunctiva, sclera, cornea, iris, and lids), ocular motility assessment, pupil examination (equal, round, and reactive to light), red reflex examination (should be bright reddish-yellow, or light gray in brown-eyed infants, and identical in both eyes). Newborns should be evaluated for cataracts, ptosis, and corneal opacities. Any abnormalities on examination should be referred to a pediatric ophthalmologist. Infants at high risk of eye problems (premature, significant neurological or developmental difficulties, metabolic or genetic diseases, positive family history of congenital cataracts, retinoblastoma, any systemic diseases associated with eye abnormalities) should be referred for a specialized eye examination by a pediatric ophthalmologist.
II. BASIC EYE INFORMATION
Structure and function of the eye are dynamic processes that begin early in pregnancy and continue throughout childhood. In term infants, the eye and visual pathway system are immature with most neonates being farsighted. During early school age, they become more nearsighted. Binocularity is established by 3–4 months of age. By 4–5 months, infants can fixate on an image with both eyes simultaneously with a steady gaze; the ability to distinguish color begins at ∼5 months. Visual acuity in infants ranges from 20/400 to 20/50. The optic nerve is completely myelinated by 2 years of age and visual acuity reaches 20/40 by that time.
The pupils are small with undeveloped reflexes until about 5 months of age. Transient nystagmus is common in infants <6 months. Extraocular muscle function is poorly coordinated for the first 6 months of life, resulting in intermittent convergent strabismus. Accommodation and convergence should be established by 24 months. There is little pigment in the iris at birth; pigmentation of the eye is complete by 6–12 months of age. The lacrimal apparatus is not fully developed at birth. Neonates don't produce tears until ∼4–6 weeks of age. Both corneal and blink reflexes are present at birth. The eye size reaches adult proportion by about 8 years of age.
Definition. Amblyopia is a reduction in corrected visual acuity in the absence of organic eye disease. It results from unequal visual stimulation during the sensitive period of visual development and is the most common cause of monocular vision loss in children.
Incidence. Estimated prevalence is 2–5% in the United States. This condition ...