Our range of vision or “ambient vision” is a key factor in our spatial orientation. Patients suffering from disorders such as glaucoma may have impaired abilities to orient themselves without realising this for a long time.

Perimetry is a technique that allows a precise assessment of a patient’s visual field. The patient sits in front of a half-open globe and stares at a fixed light while light stimuli of various intensities coming from different directions at differing intensities. Each time a light stimulus is detected, the patient pushes a button.