Concepts for automatic perimetry, as applied to the Scoperimeter, an experimental automatic perimeter

Abstract

The development of an experimental automatic perimeter, the Scoperimeter, is described. We use an oscilloscope as campimeter screen for the examination of the central 25 degrees of the visual field. The oscilloscope beam generates a homogeneous background luminance (0.1 cd/m2) and single stimulus static stimuli in any given position. The effective luminance-range of the stimuli is 3.0-3.5 log.unit. The visual field examination is controlled by a small computer system. Four examination programs written in Basic, are described. The screening programs using threshold related suprathreshold stimuli appear to be the most efficient compromise between speed and accuracy of the examination. The printout of these programs consists of a noninterpolated grey-scale presentation. Other programs perform static meridional perimetry or measure luminance threshold in 60 regularly distributed positions in the visual field. We have taken into consideration the factors that may influence the outcome of the examination: the presence of an instruction phase, the possibility to follow the progress of the examination and careful stimulus-timing. In a second paper we present clinical results we obtained using our instrument.

A new generation of algorithms for computerized threshold perimetry, SITA

“…One such period is immediately after stimulus onset to the minimum reaction time, measured to be 180-200 ms (de Boer et al 1982). FP answers are measured without using test time to perform catch trials .…”

Clinical evaluation of the Scoperimeter, an experimental automatic perimeter

“…The examination with the Scoperimeter consisted of an instructionphase followed by the phase of selected threshold measurements to determine the individual normal sensitivity curve (INSC). After the threshold determinations a suprathreshold detectionphase was performed followed by a limited assessmentphase if necessary (1).…”

“…The charateristics of the hardware (technical aspects) and software (test programs) of this instrument haven been described in detail (1). This article describes the result of a comparative clinical evaluation.…”

The Peritest, a new automatic and semi-automatic perimeter

“…This is achieved by a built-in compensation of the sensitivity gradient (gradient-adapted). This strategy has been described in extenso elsewhere (1,9,15,22). In our opinion it is at present the most efficient strategy for the detectionphase in case of glaucomatous or similar defects.…”

“…Some aspects of the manual version of the instrument are based on investigations by Greve (9). The examination strategy is based on experience with the experimental CAP ,,Scoperimeter'" of the Netherlands Ophthalmic Research Institute (1,11,22) and experience with other CAP (2,3,4,5,6,7,16).…”