The Blood-ocular Barriers and their Dysfunction: Anatomy, Physiology, Pathology

Area of Science:

• Ophthalmology
• Cell Biology
• Physiology

Background:

• The blood-aqueous barrier (BAB) and blood-retinal barrier (BRB) are critical ocular barriers.
• These barriers maintain ocular homeostasis by regulating the passage of molecules and cells from circulation.
• Tight junctions between endothelial and epithelial cells form the structural basis of these barriers.

Purpose of the Study:

• To describe the structure and function of the BAB and BRB.
• To explain the role of tight junctions in maintaining ocular barrier integrity.
• To highlight the involvement of barrier dysfunction in ocular diseases.

Main Methods:

• Review of existing literature on ocular barrier physiology and pathology.
• Analysis of the morphological components of the BAB and BRB, focusing on tight junctions.
• Discussion of clinical measurement techniques for barrier function.

Main Results:

• The BAB involves tight junctions in the iris vasculature, Schlemm's canal, and ciliary epithelium.
• The BRB comprises tight junctions in retinal vessels (inner BRB) and retinal pigment epithelium (outer BRB).
• These barriers are susceptible to pathophysiological changes leading to leakage.

Conclusions:

• Ocular barriers are essential for preventing pathogen entry and maintaining immune privilege.
• Compromised BAB and BRB function are implicated in various ocular conditions, including diabetic retinopathy and age-related macular degeneration.
• Understanding these barriers is crucial for developing treatments for vision-threatening diseases.