System and method for vision screening using interrupt signals to synchronize the sampling rate with visual evoked potential stimuli.

摘要

System for performing a vision test, comprising: a computer (14) having a CPU (453), a device (23) generating a visual stimulus, connected to said computer and connected to a screen (25) display to expose a variety of models (30) in order to be observed by a patient (17), said variety of models clear (18) and dark (19) in contrast bands, horizontally oriented, and each differing model that variety respect other models belonging to a series in the thickness of each band; we few electrodes (20-22) connected to the scalp / forehead of leather to a patient, generate electrical signals representing said patient's evoked potentials in turn in response to said range of models; and a device (11) for registering and measuring visual evoked potentials, connected to said computer (14) and coupled to said electrodes (20 - 22), said device (11) for registering and measuring visual evoked potentials various media ( 12) for detecting said signals connected to said group of electrodes (20-22), means (12) for amplifying said signals and to highlight; connected to said means (12) for detecting said signals, means (13) for converting said signals into digitized data representative of said signals, means (11, 14) for recording said data connected to said means (12) for amplifying and highlighting said signals, and means (11, 14) for measuring said data connected to said means (11, 14) for recording said data; characterized by: means for synchronizing the presentation of the variety of models with the sampling rate of said evoked potential signals, generating interrupt request signals for initiating and conducting said sampling, said means for synchronizing including: a graphics card (450) , which in turn includes a record of line count for counting horizontal lines displayed on said display screen, said graphics card (450) connected to the CPU (453) of said computer (14) and connected to said device ( 23) generating visual stimuli, wherein said graphics card generates interrupt request signals (454) at predetermined periods based on information from said count register lines, and an interrupt controller (455) connected to said graphics card ( 450), wherein said controller activates interrupt, by way of said CPU (453), said means for converting said signal is in digitized data representative of said signals, where, at the time when said CPU (453) receives a signal interrupt request (454) from said graphics card (450), said CPU (453) suspends a running program and establishes an interrupt service routine (507), wherein said CPU (453) activates said means (13) for converting and loads pattern data into said graphics card (450) for a next display frame.