A patient's visual acuity can be impaired by ailments such as choroidal neovascular lesions. Perimetry is used to measure a patient's sensitivity to differential light within their visual field, by displaying objects to the patient and measuring their response to them. Test objects – often just small spost of light – are projected onto a hemispherical surface. Kinetic perimeters display moving (hence kinetic) objects of a fix size across the visual field, which the patient must react to. A kinetic perimetry system can have a measurement range of up to 80 degrees across the hemisphere. They employ eye fixation monitors, which can be computer controlled via USB. Kinetic perimeters employ the various Goldman standards available (I-V) for use with the Goldman Visual Field. Presets for glaucoma or testing specific regions of the visual field are also offered.