Blanc a E. Marine z Ca brillo College Ap tos, California

1. Retinal Imaging ProtocolsforConstructing High Resolution MosaicsofIn Vivo PhotoreceptorCells Blanca E. Marinez Cabrillo College Aptos, California ThomasHebert, Austin Roorda, College of Optometry, University of Houston, Houston, Tx.

2. Why is retinal imaging important? Retinal imaging, the process of obtaining detailed images of the retina, it is important for: • Early diagnosis of retinal diseases. • Monitoring the progression of retinal diseases. • Studying the distribution of photoreceptors throughout the retina. AOSLO Image 1.5x1.4 deg Courtesy: Austin Roorda

3. How is retinal imaging possible? Courtesy: Austin Roorda wavefront sensing Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) light detection light delivery wavefront compensation raster scanning eye

4. To Construct a mosaic… Why is the protocol important? M O S A I C S THE B I G PICTURE… High correlation between images is important when matching them.

5. To Construct a mosaic… Why is the protocol important? M O S A I C S THE B I G PICTURE… High correlation between images is important when matching them.

6. To Construct a mosaic… Why is the protocol important? M O S A I C S THE B I G PICTURE… High correlation between images is important when matching them.

7. To Construct a mosaic… Why is the protocol important? M O S A I C S THE B I G PICTURE… High correlation between images is important when matching them.

8. To Construct a mosaic… Why is the protocol important? M O S A I C S THE B I G PICTURE… (Images from different protocols) The protocol affects the clarity of the images, the ability of the subject to fixate well, the region of the retina being imaged and the problems when creating the mosaic. High correlation between images is important when matching them.

9. AOSLO Image 1.5x1.4 deg Courtesy: Austin Roorda This shows a mosaic of approximately 9x9 degrees co-aligned with the same region of the fundus photograph.

10. P r o t o c o l Targets allow you to map the region of the retina that you want to image and to keep track of where your images should match when constructing the mosaic. It’s what you look at… how you look at it... And how we collect the data.

11. P r o t o c o l Video of a subject gazing across a line on a target. It’s what you look at… how you look at it... The subject can fixate at one point of the target, gaze across given points or line on the target, or follow a moving point of light like a laser. And how we collect the data.

12. P r o t o c o l Video of a subject fixating at one point of the target. It’s what you look at… how you look at it... The subject can fixate at one point of the target, gaze across given points or line on the target, or follow a moving point of light like a laser. And how we collect the data.

13. P r o t o c o l You may vary: It’s what you look at… • The length of your videos. • The number of • videos you take. how you look at it... • The number of images you register and sum for each location. And how we collect thedata.

14. ProtocolA Twenty-five videos, twenty seconds each. Target

15. KV ProtocolA Courtesy: Ramesh Sundaram • Drastic difference in intensity of photoreceptors in the two images. • Low correlation between images. • Edges are more prominent.

16. Protocol B Ten continuous videos where the subject gazes across given points. Target

17. Protocol B RS • Noticeable change in images from different videos. • Good foveal region due to the amount of videos taken at the fovea. • When constructing the mosaic there was a high correlation between images of the same video but not between corresponding images of different videos.

18. Protocol C One continuous video where the subject gazes across lines 1-11. Target

19. Protocol C RS • The mosaic shows uniform brightness. • Edges are not prominent. • High correlation between images. • The subject had difficulties gazing across the lines. • Fixation on the central region was minimal therefore we didn’t get a good image of the foveal region.

20. Protocol D One continuous video where the subject followed a laser point move along lines 1-11. Target

21. Protocol D RS • The mosaic shows uniform brightness. • Edges are not prominent • High correlation between images. • Subject could fixate well following the laser across the lines. • Fixation on the central region was minimal therefore we didn’t get a good image of the foveal region.

22. C o n c l u s i o n Subjectively, the best results were given by Protocol D. This protocol allows the subject to fixate well and it minimizes the effect of change in reflectivity of photoreceptors due to time difference in which the images were captured. It also allows us to match common features of neighboring frames more accurately. This creates a mosaic that is uniform in brightness, that has less visible edges, and easy to construct.

23. Acknowledgments • Center for Adaptive Optics • National Science Foundation #AST-987683 • Dr. Tom Hebert • Dr. Austin Roorda • Dr. Fernando Romero • Ramesh Sundaram • Dr. Krishnakumar Venkateswaran • Siddharth Poonja • The Roorda Lab