Volume 9 - تابستان 85-                   mjms 2010, 9 - تابستان 85-: 13-24 | Back to browse issues page

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1- Assistant Professor of Iran University of Medical Science, Optometry Department of Iran University of Medical Science
2- Assistant Professor of Tarbiat Modares University Medical Physics Dept.
3- Associated Professor of Azadeh Eslami University Medical Physics Dept.
4- Professor of Tarbiat Modares University Biostatics Dept
5- Medical Engineering M.Sc. Graduate, Tehran University of Medical Sciences.
Abstract:   (4954 Views)
Background and objective: VEP is a powerful method to study visual system via evaluating evoked potentials. Technologic and instrumental restrictions may be the reason of having studies on optical modulation and induction such as color, spatial frequency and contrast. Developments of computer software and hardware may lead to an increase in the flexibility of pattern designs. Material and methods: Visual psychophysical principles of color, spatial frequency and contrast was used to design patterns. Using the Delphi 5 package. Recording system and pattern reversing were synchronized by a software and some hardware components including an A/D, monostable and an extension Board. A trigger signal from a VEP system was used to change optical properties of patterns according to a definite algorithm. Results and conclusion: All of the optical parameters such as color, spatial frequency and contrast that have influence on visual evoked potentials can be changed independently or in an interactive manner by means of user friendly multiple windows and logical methods. Therefore, optical modulation and induction are made possible by this system. Temporal, spatial and contrast modulation can be carried out independently or dependently with a trigger signal from a VEP system. Dynamic interaction of optical parameters shows new horizons on VEP studies.
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Received: 2006/07/12 | Accepted: 2006/07/21

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