Knowledge of the anterior corneal shape is helpful in the fitting of contact lenses particularly in corneas that are misshapen by trauma, surgery, or disease. A contact lens base curve inventory or user design criteria are provided and these are used to evaluate contact lens fit and wear tolerance using a simulated clinical fluorescein test, shown in Figure NNN.4-1. The fluorescein pattern shows the contact lens clearance over the cornea. Numbers indicate local clearance in micrometers.