On Tuesday, July 15th the UR SPIE student chapter will be continuing its Summer Colloquium series. Please bring your lunch and come listen to our next presentation! Snacks and beverages will be provided.
Who: Robin Sharma
What: Two-photon fluorescence imaging of the retina in the living eye using adaptive optics
Date: 7/15/2014
Time: 11:30 am – 12:30 pm
Where: Sloan Auditorium (Goergen 101)
Abstract: Adaptive optics scanning laser ophthalmoscopy (AOSLO) permits diffraction-limited imaging of microscopic structures in the retina in living eyes. Thanks to various advances in system design and image registration software, functional imaging of different cell classes in the retina is within reach. Two-photon fluorescence imaging has a number of advantages for retinal imaging. All cells in the retina fluoresce with appropriate infrared two-photon excitation, offering the possibility of imaging every class of retinal cell, even those that are transparent in visible light. It also allows the study of molecular species whose excitation regime is in the ultraviolet, a region of the spectrum that is inaccessible in reflectance and single photon fluorescence imaging because it lies outside the transmittance spectrum of the ocular media. Additionally, it allows functional as well as structural imaging by monitoring molecular changes that are invisible with conventional imaging methods.
A two-photon adaptive optics scanning light ophthalmoscope has been developed for imaging living, anaesthetized primates. An ultrashort pulsed laser (~ 55 fs pulse-width) with a tunable central wavelength was used to excite two-photon fluorescence. Consistent with measurements made in excised retina, fluorescence emission was detected throughout the retina in vivo although the strongest autofluorescence signal originated from near the photoreceptor layer. Two-photon images of individual cells and other recognizable structures were obtained in multiple retinal layers such as the nerve fiber layer, individual rods as well as cones and retinal pigment epithelial cells. Also, the time-course of fluorescence from individual photoreceptor cells provides clues about the molecules that might be responsible for this autofluorescence. This is an important step towards noninvasively monitoring functional activity in individual retinal layers.
