It is important to understand that multiple factors can simultaneously contribute to tearing: tear film abnormalities, eyelid malposition, and nasolacrimal duct obstruction. Thus, a thorough exam in the office is necessary to determine which factors contribute to a patient's tearing problem.
The tear film is composed of three layers: outer (oil) layer, middle aqueous (water) layer, and inner layer (mucin) layer. The oil layer serves to keep the middle aqueous layer from evaporating. The mucin layer acts as a lubricant on the ocular surface. A deficiency in any or all of these layers can lead to eye irritation and watering.
Tears are primarily made from the lacrimal gland, which is located in the outside corner of the orbit (eye socket). Tears are distributed over the ocular surface with each blink, much like a windshield wiper on a car's windshield. The tear film is an important component of the eye's optical system. Thus, an abnormality of the tear film can cause blurry vision as well as irritated, dry eyes and reflex tearing.
The tear drainage system begins at the inner corner of the upper and lower eyelids. Small openings called puncta on the inner margins of the lids collect the tears, which then drain through passageways called canaliculi into the nasolacrimal sac. The sac is located between the inner corner of the eyelids and the bridge of the nose. The nasolacrimal sac empties in the nasolacrimal duct, which is a bony passageway into the nose. Tears are then swallowed.
A blockage can occur anywhere along the drainage system, from the puncta to the canaliculi, to the nasolacrimal sac and finally the nasolacrimal duct into the nose.
If only the punctal openings are blocked, a simple procedure called a punctoplasty is performed in the office under local anesthesia. More often, though, a blockage exists further downstream, usually in the nasolacrimal duct.
Examination in the office is used to determine where along this pathway a blockage may exist in a patient with tearing.
Dacryocystitis (infection of the tear sac) may occur with a nasolacrimal duct obstruction. Symptoms can range from mild redness and irritation on the inside corner of the eyelids to a severe cellulitis requiring emergent care. Antibiotics are used in the short term, but ultimately a dacryocystorhinostomy (DCR) is necessary to prevent the infection from recurring.
A procedure called a dacryosystorhinostomy, otherwise known as a DCR, is used to alleviate tearing caused by a nasolacrimal duct obstruction. Dacryocysto means "tear sac", and rhinostomy means "opening to nose." The purpose of a DCR is to create a new pathway for the tears to enter the nose directly from the nasolacrimal sac, effectively bypassing the blocked nasolacrimal duct. This is accomplished through a small incision near the inside corner of the eyelids. The incision is hidden in a skin crease, and scarring is rarely an issue. A new connection is made between the nasolacrimal sac and the nose, thus allowing tears to directly enter the nose. A DCR is a same-day surgery under local with sedation and local anesthesia.
Dr. Nicholas J. Schmitt, MD specialist: Oculoplastic Surgeon http://www.nweyeplastics.com