Visual FieldThe assessment of the extent of optic nerve damage, manifested by a reduction or loss of vision a part of the area normally from which the patient should normally see is with conducted using machines called perimeters or visual field analyzer or simply visual fields.
With this painless test, which takes several minutes for each eye, the patient is asked to confirm the lighting of a series of strategically placed light signals by pressing the button on a controller that he/she is given.
This is an examination that is absolutely necessary, since it shows the actual, functional visual impairment, as this perceived by the patient.
However, the visual fields examination begins to present findings when optic nerve damage is already extensive, established and irreversible.
Studies have shown that when the first damage appears in the visual field analysis, more than 30-40% of optic nerve fibers have already been lost . Thus, it is imperative to use new technologies in order for this damages to be identified as early as possible and avoid the bad consequences of glaucoma.