Development Of The Visual Evoked Potential Detecting Instrument

Losing eyesight is syndrome after ophthalmic operation. In order to avoiding this hurt, both diagnosing carefully or making best project before operation and monitoring the eyesight after operation are passive. The most positive method is to monitor the integrity of the vision channel using the visual evoked potential (VEP) during the operation. By doing so can we reduce the damage of the retina. The traditional measurement usually uses flash VEP and pattern VEP to monitor the vision channel. But these methods have strong side effect, they can damage eyeball and damage the patients.For the disadvantages which have mentioned above, we introduce a new kind of monitor for ophthalmic operation. We detect the integrity of the vision channel by using visual electrical evoked potential. The electrical signal with some frequency and magnitude is loaded onto the bistouries during the operation, and the VEP magnitude is a function of the distance between the bistouries and the retina, it can be detected and used to monitor the distance between the bistouries and the retina. When the distance is too close to damage the retina, the alarm will be given to the doctor to caution them to stop the operation. It is much more effective and reliable to use this method to monitor the ophthalmic operation than to use the traditional method. It can help doctor know the integrity of the vision channel and can not damage any tissue.The thesis bases on the anatomical physiology of the vision channel, and discusses generated reason of the visual evoked potential. According to its physiological parameter, we design a VEP detected system. The main study is involved some aspects as following. Firstly, we discuss the detected methods of the VEP deeply, including the choice of the stimulus, the parameter and the electrode, and find a lot of information about VEP detection. Secondly, we bring forward a new method to detect the vision channel using visual electrical evoked potential for the first time, and this thesis has introduced system framework of VEP and the design of hardware and software. Thirdly, the experiment has validated the feasibility of the system. Finally, we put forward a new method to detect EEG by using Laplacian electrode.