Abstract: An infusion apparatus for infusing liquid into a patient having a housing, a pump disposed in the housing and adapted to pump liquid through a conduit, a visual display for generating messages to the user of the infusion apparatus, a backlight associated with the visual display, and a light sensor that generates a signal indicative of the ambient light level where the infusion apparatus is being used. The infusion apparatus includes control means coupled to the light sensor and the backlight for causing the backlight to be selectively activated based on the signal generated by the light sensor. The selective illumination of the backlight saves power and is particularly advantageous when used in connection with ambulatory, battery-powered infusion pumps. The control means may cause the backlight to be activated when the ambient light level does not exceed a threshold value, and may cause the backlight to be automatically deactivated after a predetermined period of time.