A perimeter, including two types: one is a fixation forcing perimeter, and the other is an objective perimeter combined with electro-physiology under forced fixation； the perimeter comprises a fixation forcing device, a display conduction device, a perimetry display device, a feedback device for recording feedback information, and a control center for controlling the perimetry display device and collecting feedback information； the fixation forcing device comprises a negative pressure ring (2) and a negative pressure tube (3), and is adsorbed to the eyeball by negative pressure； when the eyeball moves, the fixation forcing device moves synchronously, and the fixation is forced at the same position, thereby eliminating the influence of a fixation point on the examination results of the perimeter； in the objective perimeter, an electro-physiological signal after forced fixation is automatically recorded by an electro-physiological instrument, so that the subjective response of a patient is eliminated, and the examination results are objective； and the change in the field of view can be early discovered using the electro-physiological signal as an analysis indicator.
