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The nasolacrimal duct is the tube that carries tears from the lacrimal sac into the nasal cavity. It runs downward through a bony canal beside the nose. Valves along the route help keep flow moving in one direction. The duct completes the tear drainage pathway from eye to nose.
read more about nasolacrimal duct ...It begins at the lower end of the lacrimal sac and opens beneath the inferior nasal turbinate. The channel passes through bone before entering the nasal passage. Surrounding soft tissues cushion the duct. This positioning allows efficient transfer with each blink.
The nasolacrimal duct measures about 12 to 18 millimeters in length and passes through the lacrimal canal in the maxilla. It is lined with pseudostratified columnar epithelium containing goblet cells. The valve of Hasner guards its nasal opening, preventing backflow. Its bony enclosure and mucosal lining maintain tear drainage toward the inferior meatus.
The nasolacrimal duct carries tears from the lacrimal sac into the nasal cavity. This drainage system keeps the eyes from overflowing with tears and helps flush away debris and microorganisms. Proper tear drainage through the duct maintains eye comfort and prevents infections.
Understanding the anatomy of the eye helps explain how vision works and why each part is important for healthy sight. From the cornea that focuses light to the retina that captures images, every structure plays a precise role. Learning about these components encourages better eye care and awareness of changes that could signal a problem.
By clearing used tears, it prevents overflow and keeps the surface fresh. One way valves reduce backflow that could irritate the eye. Smooth drainage supports a stable tear film. The duct's role is quiet but essential for clarity.
Tests may include dye disappearance, irrigation, or imaging to trace the channel. Findings show whether flow is open or narrowed. Early identification of issues supports simple, effective care. Documentation guides follow up over time.
It links surface lubrication to nasal drainage so the tear film renews continuously. Balanced outflow complements tear production for comfort and clarity. The duct maintains a clean optical surface during blinking. Its function keeps vision steady throughout the day.
Do both eyes share one duct? No, each eye has its own pathway.
Is the opening visible? No, it is inside the nose.
Can the duct be widened? Procedures can open narrowed segments when needed.
Cochran, M. L., et al. (2023). Anatomy, head and neck: Eye nasolacrimal. StatPearls. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK482213/
Ducker, L., et al. (2023). Anatomy, head and neck: Eye lacrimal duct. StatPearls. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK531487/
Patel, J., Levin, A., & Patel, B. C. (2023). Epiphora. StatPearls. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK557449/
EyeWiki. (2025). Dacryocystitis. EyeWiki. https://eyewiki.org/Dacryocystitis
Cleveland Clinic. (2024). Blocked tear duct: Causes, symptoms, treatment and prevention. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/14793-blocked-tear-duct