Chapter 613 Disorders of Vision
Severe visual impairment (corrected vision poorer than 6/60) and blindness in children have many etiologies and may be due to multiple defects affecting any structure or function along the visual pathways (Table 613-1). The overall incidence is approximately 2.5 per 100,000 children; the incidence is higher in developing countries, in low birthweight infants, and in the first year of life. The most common causes occur during the prenatal and perinatal time periods; the cerebral-visual pathways, optic nerve, and retinal sites are most often affected. Important prenatal causes include autosomal recessive (most common), autosomal dominant, and X-linked genetic disorders as well as hypoxia and chromosomal syndromes. Perinatal and neonatal causes include retinopathy of prematurity, hypoxia-ischemia, and infection. Severe visual impairment starting in older children can result from central nervous system or retinal tumors, infections, hypoxia-ischemia, injuries, neurodegenerative disorders, or juvenile rheumatoid arthritis.
Table 613-1 CAUSES OF CHILDHOOD SEVERE VISUAL IMPAIRMENT OR BLINDNESS
CONGENITAL
PHAKOMATOSES
TUMORS
NEURODEGENERATIVE DISEASES
INFECTIOUS AND INFLAMMATORY PROCESSES
HEMATOLOGIC DISORDERS
Leukemia with central nervous system involvement
VASCULAR AND CIRCULATORY DISORDERS
TRAUMA
DRUGS AND TOXINS
OTHER
Modified from Kliegman R: Practical strategies in pediatric diagnosis and therapy, Philadelphia, 1996, WB Saunders.
