APPARATUS FOR EVALUATING THE VISUAL FIELD OF A PATIENT

An apparatus for assessing the visual field of a patient is disclosed which utilizes a virtual image of a visual stimulus. The disclosed apparatus includes a light pattern generator which generates a visual stimulus, such as a moving fixation target, and an optical assembly which produces a virtual image of the visual stimulus projected a distance in front of the patient's eye. During measurement of the patient's visual field, the patient observes the virtual image of the visual stimulus. A centration illumination source, such as an infrared laser, also illuminates the patient's pupil with an infrared beam, which is then scattered off the patient's iris. In operation, the apparatus monitors the patient's fixation on the visual stimulus by tracking the movement of the patient's pupil using the scattered infrared image. When the center of the pupil image moves beyond a predefined threshold, a lost of fixation is indicated, from which the patient's visual field can be assessed.