ACCOMMODATION AND THE AUTONOMIC NERVOUS SYSTEM

Abstract

The rôle of the sympathetic nervous system in accommodation has been variously assumed and denied, but its active participation seems necessary to explain certain clinical and experimental phenomena to be presented in this paper. It would appear that the sympathetic system tends to adapt the eye for relatively distant objects and as such opposes the parasympathetic system, which tends to adapt the eye for relatively near objects.¹ The mechanism whereby the sympathetic system effects this distance adjustment is not obvious. It is suggested that the radial fibers of the ciliary muscle are innervated by the sympathetic system and on contraction exert a pull on the zonule which flattens the lens. They would be opposed, of course, by the circular fibers which on contraction decrease the circumference of the ciliary ring and allow greater curvature of the lens as postulated in Fincham's²modification of the Helmholtz