Aqueous Angiography in Normal Canine Eyes

Area of Science:

• Ophthalmology
• Veterinary Medicine
• Animal Models

Background:

• Assessing aqueous humor outflow is crucial for understanding glaucoma and other ocular conditions.
• Canine models are valuable for studying ocular physiology and disease due to similarities with human eyes.
• Current methods for visualizing aqueous humor dynamics in vivo can be limited.

Purpose of the Study:

• To establish a clinically applicable aqueous angiography (AA) technique in normal dogs.
• To compare the findings of AA with intravenous scleral angiography (SA).
• To evaluate the utility of AA for visualizing conventional aqueous humor outflow (CAHO) pathways.

Main Methods:

• Examined canine cadaver and live normal dog eyes.
• Utilized a gravity-fed trocar system for intracamerally (IC) delivered indocyanine green (ICG) in cadaver eyes.
• Performed in vivo AA via IC bolus of ICG and intravenous SA using ICG in live dogs, imaging with a confocal scanning laser ophthalmoscope.

Main Results:

• Intracameral AA visualized CAHO pathways in vivo, showing sectoral outflow patterns in the superotemporal sclera.
• Pulsatile aqueous movement was observed in some dogs during AA.
• SA showed comparable fluorescence patterns to AA, with evidence of weak pulsatile aqueous humor outflow.

Conclusions:

• Both AA and SA in dogs allow in vivo visualization of the CAHO pathway and its vascular components.
• Intracameral AA demonstrates potential as a more useful modality for assessing aqueous humor outflow in dogs.
• AA in dogs offers potential utility for evaluating CAHO in vivo, supporting its use in this important animal model.