Anatomy & Education
Lacrimal System Anatomy
Lacrimal System Anatomy
The lacrimal system produces, distributes, and drains tears. A healthy tear film is essential for corneal health, clear vision, and comfort. When any part of the drainage pathway is obstructed, tears overflow onto the cheek (epiphora) and may become a source of chronic infection.
Overview
The lacrimal system has two functional components: the secretory system (which produces tears) and the excretory system (which drains them). The two components must be in balance — inadequate drainage causes overflow, while inadequate production causes dry eye.
Tears flow across the ocular surface from lateral to medial with each blink, collecting in the medial lake (lacus lacrimalis) near the inner corner of the eye. They then enter the drainage system through small openings at the inner edge of each lid margin.
Tear Film & Production
The tear film is a three-layer structure essential for optical clarity and corneal nutrition:
Lipid Layer (outer)
Source: Meibomian glands (in tarsal plate)
Prevents evaporation; stabilizes the tear film
Aqueous Layer (middle)
Source: Lacrimal gland & accessory glands (Krause, Wolfring)
Provides oxygen, nutrients, and antibacterial proteins to the cornea
Mucin Layer (inner)
