accommodation (visual)

Introduction

Adjustment or adaptation to bring objects into focus, usually increase to an object coming close to the eye. Accommodation involves a neural circuit from the eye to the visual cortex & back. Focusing is facilitated by stimulating the smooth muscle of the ciliary body to contract, thus enabling the shape of the lens to change. This is accommodation. During accommodation, the pupil also constricts. Both accommodation & pupillary constriction are facilitated by contraction of muscle innervated by parasympathetic components of CN 3.

Pathology

• the syphilitic (Argyl-Robertson) pupil constricts during accommodation, but does not react to light

Additional terms

• Argyl-Robertson pupil
• ciliary body
• pupil (P)