Abstract
Purpose :
Non-arteritic anterior ischemic optic neuropathy (NAION) is the second most common optic neuropathy in adults, yet its etiology remains uncertain. This research aims to address this gap by employing various analytical methods to visualize and reconstruct the vascular structures of the human optic nerve head to enhance our understanding of vascular perfusion patterns while laying the groundwork for future studies on biomechanical stresses affecting optic nerve head blood vessels.
Methods :
Serial sections (10 micron thick) obtained from a human with clinically-presumed NAION were stained with Hematoxylin and Eosin (H&E), a fraction of which were scanned and digitized using the Zeiss Axio Scan Z1 microscope. Zen (Zeiss) software, Intellesis an automated image segmentation tool, and Arivis facilitated 3D reconstruction and differentiation of veins and arteries. Separately, we have dissected seven complete orbits from fresh cadavers. These specimens are being studied either: 1) by preparing serial orbital cross sections that will be stained histochemically and immunohistochemically, then analyzed with respect to location of arteries and veins, connective tissue and neural tissue; or 2) by prolonged optical clearing to be able to visualize it using Light sheet fluorescence microscopy.
Results :
Two methods are providing significant insights into human optic nerve head vasculature. Our analysis of serial, H&E-stained cross sections of human optic nerve, aided by Zeiss software, is yielding the foundation for a 3D reconstruction of the complex vascular anatomy. Verhoeff-Van Gieson staining is also being applied to highlight blood vessels. Our second anatomical method uses Light Sheet Fluorescence Microscopy to provide 3D and 4D imaging of entire human orbits (freshly dissected from cadavers, with infusion of DiI into the ophthalmic artery). Automated image segmentation is enabling categorization of posterior ciliary arteries and orbital veins.
Conclusions :
This multi-pronged approach marks a significant step forward in exploring the vascular terrain of the human optic nerve. The comprehensive analysis of vascular structures, coupled with advancements in technology and artificial intelligence, sets the stage for more nuanced investigations into optic nerve biomechanics. The results not only enhance our understanding of NAION but also other vascular related optic neuropathies.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.