Some Possibilities of the Peritest Automatic and Semi-Automatic Perimeter

The Peritest is a computer-assisted perimeter which purposely offers the possibility of both automatic and semi-automatic examination modes. A fast multiple-stimulus screening is possible next to extensive automatic assessment. The instrument uses LEDs for the 206 stimuli, of which 151 are located within 25° eccentricity. The examination strategy uses the system of threshold-related suprathreshold presentations. The assessment phase may use 0.2 or 0.6 log unit steps. The progress of the examination can be followed on a LED monitor. The experience of over 800 examinations with the Peritest has shown that the instrument is able to do a relatively quick examination with reproducible results. The examination time varies from 4 minutes for a semi-automatic screening to 15 minutes for a completely automatic detection and assessment. The detection rate is better than that of classical kinetic perimetry. This is demonstrated by the fact that 70% of early glaucomatous defects which are usually overlooked by kinetic perimetry are detected. The non-interpolated grey scale printout on a special chart demonstrates the configuration of defects satisfactorily and makes comparison with classical kinetic perimetry possible. The defect volume in separate areas of the visual field or in the whole visual field can be easily expressed in numbers. With some precautions this could be used for describing changes in the visual field.