In Vivo Near-Infrared Fluorescence Imaging of Aqueous Humor Outflow Structures.

Area of Science:

• Ophthalmology
• Glaucoma Research
• Surgical Visualization

Background:

• Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
• Understanding the aqueous humor outflow pathway is crucial for glaucoma management.
• Current methods for visualizing the outflow system during surgery are limited.

Purpose of the Study:

• To visualize the functional aqueous humor outflow system in POAG patients.
• To assess the efficacy of indocyanine green (ICG) dye combined with viscoelastic solution for intraoperative visualization.
• To identify patent collector channels and aqueous veins.

Main Methods:

• A mixture of indocyanine green (ICG) and a high-viscosity viscoelastic solution was injected into the Schlemm canal.
• 10 patients with POAG undergoing canaloplasty were included.
• Visualization of dye progression along the Schlemm canal and into collector channels and aqueous veins was performed.

Main Results:

• ICG dye injection clearly visualized the functional portions of the conventional outflow pathway.
• Partial reflux of dye indicated intrachannel resistance.
• Filling of collector channels and aqueous veins was observed only in patent segments of the Schlemm canal.
• Retrograde filling of structures, possibly in the iris, was noted.

Conclusions:

• ICG dye combined with viscoelastic solution provides effective intraoperative visualization of the aqueous outflow system.
• This technique aids in identifying functional segments of the outflow pathway during glaucoma surgery.
• The method may help in assessing surgical outcomes and understanding POAG pathophysiology.