The device works by distinguishing what is known as light points in space, and therefore if the patient cannot distinguish these points, the computer will consider that there is an area affected by damage in the field of vision, and the device will consider that spot as a blind spot, although there is a natural blind spot in each eye intact as well . It aims to check the integrity of the range of vision for each individual eye, including central and peripheral vision (sides). It is an important integral part of every comprehensive visual examination, especially Glaucoma and retinal disease.