Computer assisted electroretinogram data acquisition and analysis Nick Balge, Andrew Dias, Whitney Johnson, Dan Jonovic Advisor: Professor Mitch Tyler Client: Dr. Bikash Pattnaik 10/20/200810/21/2008 2 of 20 Contents Table of Figures ............................................................................................................................................. 3 1. Background ........................................................................................................................................... 4 2. Applications/Motivation: ...................................................................................................................... 5 3. Problem Statement: .............................................................................................................................. 6 4. Lab layout: ............................................................................................................................................. 6 5. Design constraints: ................................................................................................................................ 7 6. The current interface ............................................................................................................................ 8 7. Design 1: Tweak Existing Interface ....................................................................................................... 9 A. Functionality ..................................................................................................................................... 9 B. GUI Modification ............................................................................................................................. 10 8. Design 2: Complete GUI Overhaul ...................................................................................................... 11 A. GUI Plans ......................................................................................................................................... 11 B. GUI Design ....................................................................................................................................... 12 9. Design 3: Start over from scratch ....................................................................................................... 13 A. Existing Solutions ............................................................................................................................ 13 B. Programming Languages ................................................................................................................. 14 C. The Design ....................................................................................................................................... 14 10. Design Matrix .................................................................................................................................. 15 A. Definition of Criteria ....................................................................................................................... 15 11. Potential Problems .......................................................................................................................... 16 12. Future Work .................................................................................................................................... 17 13. Conclusion ....................................................................................................................................... 17 14. References ...................................................................................................................................... 18 15. Appendix A: Product Design Specifications .................................................................................... 1910/21/2008 3 of 20 Table of Figures Figure 1: Example of ERG wave .................................................................................................................... 4 Figure 2: Measuring the amplitudes and times of waves ............................................................................. 5 Figure 3: Organization of our client’s lab ...................................................................................................... 6 Figure 4: A solution valve opener ................................................................................................................ 7 Figure 5: GUI for the original interface ......................................................................................................... 8 Figure 6: The existing backend ..................................................................................................................... 9 Figure 7: Possible GUI Overhaul ................................................................................................................. 11 Figure 8: The Design Matrix ........................................................................................................................ 1610/21/2008 4 of 20 1. Background An electroretinogram (ERG) is used to measure the electrical responses of various cell layers in the retina (Medline, 2007). This response is gathered by placing an electrode either on the retina or the skin surrounding the eye, connecting the other electrode to ground, and stimulating the retina with light; the intensity and wavelength of the light stimulus is often varied. The result of the light stimulus is a triphasic wave that consists of a, b, and slow-waves (Figure 1). These different components represent separate layers of cells in the retina. The a-wave is called the “late receptor potential” and reflects the physiological health of photoreceptors in the outer retina. The b-wave reflects the health of the outer cell layers of the retina and the slow-wave provides information on the bipolar and ganglion cells (Creel, 2008; Ye and Goo, 2007). Measurements taken from the wave include the amplitude of the a-wave from time zero, the amplitude of the b-wave with respect to the a-wave, the time between the flash and trough of the a-wave, and the time between the flash and the peak of the b-wave (Figure 2). The measurement of the time from flash onset to wave peak is called the implicit time. The b/a wave ratio is a good indicator of ischaemia, or insufficient blood flow in a central retinal vein obstruction (Matsui, Y et al, 1994). Figure 1: Example
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