Ocular accommodation in human infants.
The present longitudinal investigation evaluated the proficiency of the human ocular accommodation system during the 20-week period after birth. Fourteen human infants were tested at specific intervals during the age of 2 through 20 weeks. At each age the refractive state of the eyes during fixation of a vertical-striped, high-contrast stimulus pattern presented at viewing distances ranging from 10 to 50 cm was measured by dynamic retinoscopy. The accommodative performance of the infants demonstrated the following: (1) the newborn accommodation system executes reasonably appropriate responses to weak dioptric stimuli; (2) accommodative accuracy generally decreases from 2 through 8 weeks of age; and (3) accommodative accuracy increases beyond 8 weeks of age until adult-like levels of proficiency are attained between 16 and 20 weeks. Factors which could affect individual accommodative responses and explanations for the observed developmental pattern of accommodative performance are discussed.
D000065:Accommodation, Ocular; D000328:Adult; D000367:Age Factors; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012029:Refraction, Ocular; D014787:Vision Tests / Q000295:instrumentation / Q000379:methods