Punctum caecum

Punctum Caecum is a small anatomical structure located in the eye. It is part of the lacrimal apparatus, which is responsible for the production and drainage of tears. The primary function of the punctum caecum is to serve as the initial entry point for tears to be drained from the eye's surface into the nasolacrimal duct, eventually leading to the nasal cavity. This process is essential for maintaining proper eye health and vision, as it helps to remove debris and maintain the eye's moisture balance.

Anatomy

The punctum caecum is found at the medial (inner) margin of each eyelid, specifically at the junction where the upper and lower eyelids meet, known as the canthus. There are two puncta in each eye, one located on the upper eyelid (superior punctum) and one on the lower eyelid (inferior punctum). Each punctum appears as a small, round opening that is barely visible to the naked eye.

Function

The primary role of the punctum caecum is to facilitate the drainage of tears from the eye's surface. Tears are produced by the lacrimal gland and spread across the surface of the eye with each blink. These tears collect at the eye's inner corner, where the punctum caecum acts as a conduit, allowing tears to enter the lacrimal canaliculi, small channels that lead to the lacrimal sac. From the lacrimal sac, tears flow down the nasolacrimal duct and into the nasal cavity, where they are reabsorbed.

Clinical Significance

The punctum caecum can sometimes be involved in eye-related health issues. Blockages or abnormalities in the punctum caecum or associated lacrimal apparatus can lead to conditions such as dacryocystitis, an infection of the lacrimal sac, or epiphora, which is excessive tearing due to improper drainage. Treatment for these conditions may involve procedures to clear the blockage or, in some cases, surgery to create a new drainage pathway.

See Also

• Lacrimal apparatus
• Tear duct
• Eye anatomy