A new non-contact corneal aesthesiometer (NCCA).

A novel method for testing the corneal nerve function, through non-invasive measurement of corneal sensitivity, is presented. The method of using a controlled pulse of air to stimulate the corneal surface is described. Technical information of the aesthesiometer's construction is given. Examples of the ability of the instrument to accurately locate the corneal sensitivity threshold using either a method of constant stimuli, or a method of limits, is described for 14 normal, non-lens wearing eyes. Measurements are made in millibars of air pressure required. Mean normal values found were 0.342 +/- 0.068 millibars. Discussion is made of the instrument's mode of action, its advantages over other invasive instruments, and potential clinical application.