Prism induced accommodation in infants 3 to 6 months of age.

Convergence-accommodation, one of several cross-linkages in the oculomotor system is manifested by opening the accommodative feedback loop and increasing the vergence input. We elicited this response in human infants aged 3-6 months by placing a 15 delta prism (base-out) before one eye while they viewed a diffuse patch of light. Accommodation was measured and ocular alignment was confirmed with a video photorefractor. The convergence-accommodation response is therefore present during a time when blur driven accommodation and disparity vergence are maturing. The gain of convergence-accommodation (expressed as the stimulus CA/C ratio) appeared to be greater for infants than adults.