1. A method of simultaneously evaluating a visual field and retinal function in a patient, the method comprising a. using an instrument containing a light source to shine a relatively stronger pulse of light on the retina until the patient indicates lack of seeing the light source thereby indicating bleaching the patient's retinal photoreceptors; b. using the instrument to shine a plurality of subsequently weaker pulses of light than in step a on the retina until the patient indicates seeing the light source thereby measuring recovery of the bleached retinal photoreceptors, and c. assessing the time interval between steps a and b as the patient's photoreceptor recovery thereby indicating the patient's photoreceptor health compared to photoreceptor health of a normal individual.