Functional morphology of rabbit iridial ciliary processes.

Area of Science:

• Ophthalmology
• Vascular Biology
• Cell Biology

Background:

• The iridial ciliary processes possess a distinct vascular architecture compared to major ciliary processes.
• The pigment epithelium (PE) of iridial processes exhibits unique ultrastructural features, including a basolateral labyrinth.

Purpose of the Study:

• To investigate the vascular supply and ultrastructure of iridial ciliary processes.
• To examine the response of iridial ciliary process vasculature and PE to paracentesis.

Main Methods:

• Scanning electron microscopy of vascular resin casts.
• Transmission electron microscopy of iridial ciliary processes.

Main Results:

• Iridial ciliary processes have dedicated arterioles and isolated venules, distinct from the major ciliary processes' shunt system.
• The PE of iridial processes forms an extensive basolateral labyrinth.
• Paracentesis induced capillary enlargement, leakage, and protein exudation in iridial processes, but not major ones.

Conclusions:

• Iridial ciliary processes may primarily function in fluid reabsorption under normal conditions.
• The blood-aqueous barrier in iridial processes is sensitive and can break down, leading to protein exudation after procedures like paracentesis.