Application of Second Harmonic Imaging Microscopy to assess structural changes in optical
nerve head structure ex vivo
Annie Lay
Mentor: Dr. Donald J. Brown
Glaucoma represents the second leading cause of blindness worldwide. The loss of vision is
known to be associated with the death of retinal ganglion cells, or RGC, mainly due to damage
of the axons in the optical nerve head (ONH). These injuries seem to be caused by the structural
distortion in the ONH and the mechanical vulnerability of the lamina cribrosa, which is the ONH
region composed of collagen beams making up the channels through which axon bundles leave
the eye. In this study, we use multiphoton microscopy known as Second Harmonic Imaging
Microcopy, or SHIM, to generate second harmonic signals from collagen allowing direct optical
imaging of the lamina cribrosa. SHIM permits us to compare the structure of age matched optic
nerve heads and lamina cribrosa between normal and glaucomatous eyes. My results include
three-dimensionally reconstructed data sets of the optical nerve head structure from patients with
and without glaucoma. These second harmonic images demonstrate optic disc deformation and
cupping present in glaucoma patients. Second Harmonic Imagining Microcopy has been a
valuable tool in this study and presents great potential for future projects.