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

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.

RPE Pre-exposure image Courtesy Jessica Morgan

150 uW Exposure for 15 minutes Courtesy Jessica Morgan

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

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

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.

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

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

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

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.

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-987683 And rest of the Center for Visual Science and Center for Adaptive Optics family that helped to make my research in Rochester, NY successful!

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