An appreciation of the anatomy of normal tear flow is essential to understanding abnormal tearing.

• Tear production starts in the lacrimal gland which is located in the upper lid. Additionally there are multiple smaller secretory glands located along both the upper and lower lids that provide oil and mucous to the tear film.

• Tears flow across the front of the eye to lubricate, nourish and cleanse the surface.

• Tears “exit” from the ocular surface both through evaporation and through two small drainage holes (puncta) which are located near the inner corner of both the upper and lower lids. These openings, called puncta, collect the tears which have been propelled horizontally along the lower lid and into the corner by the act of blinking.

• From these two drainage holes the tears flow “down-hill” through two drainage pipes (canalicula) and into the drainage sack (lacrimal sac).

• From the lacrimal sac tears descend directly into the nose and back of your throat.

The continuous flow of fresh tears across the eye’s surface is critical to the health of our external ocular tissues: the cornea and conjunctiva. We produce about 2-3 ounces of tears daily. A reduction in tear production (e.g., dry eyes) will result in a compromise of our ocular tissues and discomfort. An increase in tear production or a blockage of tear outflow will result in tears either running down our cheeks or into our nose. A simple, everyday demonstration of the result of this anatomy occurs when our nose “runs” when we cry. Similarly those of us taking drops will often “taste” the drops that we instill into the eye.

Abnormalities of Tear Flow (Tearing):
Any problem that slows or blocks the drainage of the tears from the eye will result in annoying tearing (epiphora). (Just like a kitchen sink will overflow if the drain is blocked, the tears will run down the side of your face if your tear drains are blocked.) A blockage can occur anywhere along the drainage system connecting the lower lid to the nose. If the blockage is partial, it can often be reversed (opened) by a simple, painless, in-office procedure call “Dilation, Probing & Irrigation”. During this procedure the eye is numbed with drops, a small canula (a tiny hose) is inserted into the tear drain in the lower lid and the passages “flushed” with warm salty water. If the patient can taste the salty water in the back of the throat, the test indicates that the passages can be opened. This simple, painless test is both diagnostic and therapeutic:

• Diagnostic in that it can indicate if the blockage is complete or partial.
• Therapeutic in that the simple act of irrigation will often open the blockage permanently.

If the blockage is “complete” and the doctor is unable to flush the salt water into the nose during the Dilation, Probing & Irrigation procedure, surgery is indicated. This is often as simple as enlarging the drain hole (an office procedure) but may require a more extensive operating room procedure called a “DCR” (DacryoCystoRhinostomy). During the DCR outpatient procedure, a direct opening is made connecting the tear sack and the nose.

Although tearing abnormalities occur most commonly with age, they also can occur in infancy. Most children are born with their small tear “drainage pipes” not yet completely developed. Fortunately, during this early period, infants have little or no tear production and the absence of good drainage is not a problem because there is very little to drain. As infants develop, their tears begin to be more abundant and their tear drains begin to open. If tear production begins before the “drainage pipes” are developed, infants will develop a sticky, mucous discharge in their eyes. This may continue until eight months of age, at which time most infants have fully developed tear drains. This is considered “normal” and requires no treatment other than prophylactic soaking and cleansing, and occasionally antibiotic eye ointment.

Abnormalities of Tear Production (Dry Eyes):
With age, our tear production decreases. As a result, our eyes are no longer adequately lubricated and they become “dry”. Gritty, sandy, scratchy, itchy, burning, achy, tired, sticky symptoms result. Taking advantage of our knowledge of the anatomy of tear-flow, small “plugs” are used to block the tear drains (puncta) in an attempt to retain those tears that are still being produced. This procedure is called punctal occlusion and is done as an office procedure. Punctal occlusion as a treatment for dry eyes can be either supplemented or replaced by the use of other topical agents: Omega 3-6-9 pills, Artificial Tears, Restasis eye drops (see Dry Eye article).