The question can be answered in many ways. First of all, there are visual field devices used to perform automated static perimetry and those for manual kinetic perimetry. Automatedtests utilize computer programs to vary test speed, target size, and luminance. Automated tests also benefit from standardized testing conditions, which can be used to interpret results across machines, and efficient testing strategies (more on these later). They present light stimuli of varying luminance to the patient in specific locations for a given duration of time before the next stimulus is presented (0 dB is a maximal stimulus intensity, 10 dB is 1-log unit lower than the maximum, 20 dB is 2 log-units lower, etc). Automated devices provide results that can be directly compared to age-adjusted normative values, which have been derived from testing hundreds of normal subjects. Commonly used automated perimeters are the Humphrey visual field analyzer (HFA) (Zeiss, Inc., Dublin, CA) and the Octopus perimeter (Interzeag/Haag Streit, Koeniz, Switzerland). Manualperimeters require a skilled examiner to present targets to the patient. Both static and kinetic testing can be performed manually. In kinetic testing, a moving target of varying size and luminance is presented to the patient. Manual kinetic perimetry is more flexible and interactive for the patient, and it provides the opportunity to evaluate the far peripheral visual field [1]. Also in existence is a semi-automated kinetic perimetry program on the Octopus perimeter in which a computer program performs kinetic perimetry.