1. Ophthalmic Instruments & Ex Vivo Retinal Pigment Epithelium Autofluorescence
By: Andrew Williams
University of Rochester
Primary Investigator: Dr. David Williams, PhD
Mentor: Dr. Jennifer Hunter, PhD
Home Institution: Xavier University of Louisiana

3. Autofluorescence
The Retinal Pigment Epithelium nourishes the rods and cones.
It develops a substance called lipofuscin.
It is the lipofuscin in the cells causing the light emitted onto the retina to autofluoresce.

4. RPE Pre-exposure image
Courtesy Jessica Morgan

5. 150 uW Exposure for 15 minutes
Courtesy Jessica Morgan

6. These light intensities were expected to be safe.
RPE immediately Post-exposure Image
Dimming is a phenomenon that occurs in vivo and ex vivo for light intensities of 18.8 mW/cm2 on the retina.
These light intensities were expected to be safe.
Long term dimming may completely recover or cause long term changes depending on the light level.
Courtesy Jessica Morgan
150 uW Exposure Location

7. Goals
What are the light exposures of ophthalmic devices currently used in retinal surgery?
Do they cause dimming ex vivo?

10. Methods: Dimming Ex Vivo
Imaging
Exposure
1º Field of View
1º Field of View
After location was found an image was taken of that location.
Power levels of the imaging light source were recorded to ensure safe light exposures would be used to image the retina.
Images of the retina were taken at a 1º field. Block half of the image and expose area for 15 min. Then take a post image of the full 1º field.

12. RPE Pre-Exposure Image
20 Gauge B & L Millennium Exposure Location

13. Fluorescence Half Blocked Exposure Image
20 Gauge B & L Millennium Exposure Location

14. RPE Post-Exposure Image
20 Gauge B & L Millennium Exposure Location

16. Conclusions
For the Bausch & Lomb Millennium, dimming does not occur in retinal pigment epithelium ex vivo at the exposure time of 15 minutes.
More trials are necessary to confirm that dimming occurs for the Photon light source.
There is a continued quest for light intensities and light exposure durations that are safe for the human retina in vivo.

17. Acknowledgements I would like to thank: Dr. Jennifer Hunter, PhD
Dr. David Williams, PhD
Jessica Morgan
Dr. Mina Chung, MD
Ben Masella
Bob Wolfe
Lana Nagy
Dr. William Fischer
Funding Provided through the Center for Adaptive Optics, a National Science Foundation Science and Technology Center (STC) AST
And rest of the Center for Visual Science and Center for Adaptive Optics family that helped to make my research in Rochester, NY successful!

18. References
Bennett, Arthur G. Clinical Visual Optics. Butterworths Inc. Second Ed pp. 9-22, pp
Rodieck, R. W. The Vertebrate Retina: Principles of Structure and Function. W. H. Freeman and Company pp
Delori, Francois C. “Maximum permissible exposures for ocular safety (ANSI 2000), with emphasis on ophthalmic devices.” Optical Society of America. Vol. 24, No. 5. May pp
Inoue, Y. “A2e mediated phototoxic effects of endoilluminators.” Br. J. Ophthalmol. Vol. 90. February pp
Lamb, Laura E. “A2e: A Component of Ocular Lipofuscin.” Photochemistry and Photobiology. Vol pp
“Endoilluminator.”
“Endoilluminator.”
“Mathematics.”