The small opening near the inner corner of your eye is a normal anatomical feature present in every healthy eye. This tiny structure is not a defect but a necessary part of the body’s system for managing tear fluid. It prevents the buildup of tears that would otherwise spill over your eyelid onto your cheek. Observing this feature often happens only when a person looks closely at their reflection or experiences mild irritation.
Identifying the Punctum Lacrimale
This opening is scientifically known as the punctum lacrimale, which translates from Latin to “lacrimal point.” There are two openings on each eye: one on the margin of the upper eyelid and one on the margin of the lower eyelid. Both puncta are situated close to the nose, in the area called the medial canthus, resting on a slight elevation of tissue known as the lacrimal papilla.
The punctum appears as an often pinkish opening, typically measuring only about 0.2 to 0.3 millimeters in diameter. To locate it, gently pull your lower eyelid down and look toward the inner corner of your eye. These two openings are positioned to oppose one another, nearly touching when the eyelids are fully closed.
The punctum serves as the visible entrance to a channel called the canaliculus, a duct that extends away from the eyelid margin. This channel begins vertically for about two millimeters before making a sharp turn inward, running horizontally along the lid. It is the beginning of the entire tear drainage pathway, the nasolacrimal system.
The Essential Function of Tear Drainage
The primary purpose of the punctum is to act as the receiving port for tears that constantly bathe the surface of the eye. Tears are produced by the lacrimal glands, spreading across the cornea to lubricate, nourish, and cleanse the eye with every blink. Once their job is done, the fluid must be cleared from the eye to prevent blurring of vision and overflow.
The drainage process relies on the lacrimal pump mechanism. When you blink, the orbicularis oculi muscle contracts and compresses the lacrimal sac, which is further down the drainage path. Simultaneously, the closing of the eyelids brings the upper and lower puncta together, squeezing tears into the canaliculi.
When the eyelids open, the compression is released, creating a negative pressure that pulls the tear fluid further into the drainage system. Once tears pass through the punctum and the canaliculi, they converge and drain into the lacrimal sac, a small reservoir located beside the nose. From the lacrimal sac, the fluid travels down the nasolacrimal duct, eventually emptying into the nasal cavity.
This explains why crying often causes a runny nose, as excess tears drain directly into the nose and mix with mucus. The entire system is a continuous, low-pressure network designed to maintain the delicate balance of moisture on the eye’s surface.
When the Small Eyelid Hole Causes Trouble
While the punctum is normally an efficient drain, certain conditions can cause it to malfunction, leading to noticeable symptoms. The most common issue is punctal stenosis, which is a narrowing or partial closure of the opening. This narrowing reduces the eye’s ability to drain fluid, resulting in chronic excessive tearing known as epiphora.
Punctal stenosis may occur due to age-related tissue changes, chronic inflammation of the eyelid margin like blepharitis, or as a side effect from certain topical medications, such as glaucoma eye drops. If the punctum is narrowed, the primary symptom is a persistently watery eye.
A more serious issue occurs if the obstruction is further down the drainage path, leading to an infection of the lacrimal sac called dacryocystitis. Stagnant tears allow bacteria to accumulate, causing infection. Symptoms include a painful, tender swelling or lump near the inner corner of the eye, often accompanied by redness, discharge of pus or mucus, and sometimes a fever.
If the eyelid hole appears swollen, red, or if you experience persistent excessive tearing, pain, or discharge, seek medical attention. These symptoms necessitate an examination by an eye care professional to determine the location and cause of the blockage or infection.