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Updated: May 8, 2025
Deep Vascular Imaging in the Eye with Flow-Enhanced Ultrasound
Published on: October 4, 2021
Visualization of porcine and human aqueous humor outflow tract anatomies with transparency enhancement
Yuichi Asahina1, Makoto Aihara2, Takashi Miyai2
1Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. yasahina_oph@yahoo.co.jp.
Purpose:
There is no established method for visualizing the three-dimensional (3D) structure of the aqueous humor outflow tract. This study attempted to visualize the 3D structures of porcine and human ocular tissues, particularly the aqueous humor outflow tract using a transparency reagent composed of 2, 2-thiodiethanol.
Study Design:
Clinical and experimental.
Methods:
The porcine eyes were collected in Japan, and the human eyes were imported from the United States. The human eyes were obtained from a 64-year-old Caucasian woman, arriving 7 days after her death. The specimens were formalin-fixed upon arrival, fluorescently labeled, optically cleared using a transparency-enhancing reagent, and visualized using a confocal microscope.
Results:
Both porcine and human eyes were visualized to the extent that the choroidal vessels were observed on gross examination. The aqueous humor outflow tract was clearly observed as a luminal structure in the porcine eye, mainly depicted by autofluorescence, and in the human eyes as a luminal structure continuing from the trabecular meshwork without fluorescence.
Conclusion:
Observations using transparency-enhancing technology enabled us to obtain 3D images useful for visualizing ocular tissues, especially the aqueous humor outflow tract.
