Tear duct blockages are a common issue affecting the eye’s drainage system, often leading to uncomfortable symptoms. A specific physical obstruction is the lacrimal stone, medically known as a dacryolith. This hardened deposit forms within the tear passages, preventing the natural flow of tears. Understanding how these stones form and the anatomy they affect is key to effective treatment.
Defining the Lacrimal System and Dacryoliths
The lacrimal system is the body’s network responsible for collecting tears from the eye’s surface and draining them into the nasal cavity. The process begins at two tiny openings on the inner edge of the eyelids, called the puncta, which act as entry points for the tears. From there, tears flow into small channels known as the canaliculi, which converge into the lacrimal sac, located next to the nose.
This sac connects to the nasolacrimal duct, a bony channel that directs the tears downward, emptying them into the nose. A dacryolith is a stone-like concretion that forms within this drainage system, most frequently developing within the lacrimal sac or the nasolacrimal duct.
Unlike kidney stones, dacryoliths are not primarily composed of pure calcium but are largely organic in nature. Chemical analysis shows they consist mainly of mucopeptides, sloughed-off epithelial cells, and other cellular debris, often laid down in laminated layers. Inorganic elements, such as calcium, magnesium, and potassium, are also present but constitute a smaller percentage of the stone’s mass. The formation of a dacryolith is thought to be triggered by chronic inflammation or stagnation within the tear duct, causing this organic material to accumulate and slowly harden.
Recognizing the Signs of Blockage
The most prominent sign of a dacryolith blockage is persistent, excessive tearing, a condition known as epiphora. Since the stone physically prevents tears from draining into the nose, the fluid backs up and spills over the lower eyelid onto the cheek. This symptom often worsens when a person is exposed to cold, wind, or bright sunlight, which naturally stimulate increased tear production.
The stagnant pool of tears and mucus that forms behind the obstruction creates an environment ideal for bacterial growth. This backup often leads to a secondary infection of the lacrimal sac, termed dacryocystitis, which causes acute and painful symptoms. Patients may observe tender, painful swelling and redness near the inner corner of the eye, adjacent to the nose.
Pressing on this swollen area can sometimes cause a thick, purulent discharge to reflux out through the puncta onto the eye’s surface. Other symptoms include crusting on the eyelashes, especially upon waking, and recurrent eye infections. These signs indicate that the natural drainage mechanism has failed due to a physical obstruction.
Clinical Procedures for Removal
The clinical evaluation for a dacryolith begins with diagnostic tests to confirm the location and severity of the blockage. A dye disappearance test is a simple initial procedure where a fluorescent dye is placed in the eye to see how quickly it drains; prolonged retention suggests an obstruction. A physician may also perform probing and irrigation, where a small instrument is inserted into the tear duct to flush the system and feel for the physical presence of the stone.
Imaging studies, such as dacryocystography or computed tomography (CT), provide a detailed view. These help pinpoint the stone’s size and exact location within the lacrimal sac or duct. Once a dacryolith is confirmed, the definitive treatment for removal is typically a surgical procedure called dacryocystorhinostomy (DCR).
The goal of a DCR is to create a new, permanent bypass channel between the lacrimal sac and the nasal cavity, rerouting the tear flow around the blocked nasolacrimal duct. The DCR procedure can be performed using two main approaches: external or endoscopic.
The external approach involves a small incision on the skin beside the nose, allowing direct access to the lacrimal sac and the underlying bone. The endoscopic approach is minimally invasive, using a camera and instruments inserted through the nostril to reach the blockage without any external skin incision. During either procedure, the surgeon removes the dacryolith and then opens the bone to connect the lacrimal sac directly to the nasal mucosa. A small silicone tube is often temporarily placed in the new passage to keep it open during the initial healing phase.