Studies on the control of accommodation and convergence

A control model of accommodation and convergence has been developed further, in accordance with the physiology of the eye. It is argued on control theory grounds for accommodation, and more tentatively for convergence, that effort is able to be exerted on both sides of a resting point which lies at an intermediate position between the extremes of the range. Thus convergence and active divergence, in addition to positive and negative accommodation, are examined