The Anatomy of the Lacrimal Gland

The lacrimal gland is a small, almond-shaped gland that sits in the upper, outer corner of the eye socket, just about parallel to the outer edge of your eyebrow. It produces the aqueous (watery) portion of tears.

Tears have three layers—water, mucus, and oil layers. Tears are essential for keeping the eye's surface moist, washing away dirt and debris, and helping to refract (bend) light. 

Certain infections, diseases, and other factors can lead to inflammation of the lacrimal gland. That inflammation can play a role in dry eye disease (DED), a condition that affects about 20% of Americans and is caused by problems with the quality, quantity, and/or drainage of tears.

Without adequate lubrication, your eyes can look red and feel irritated, burning, and gritty—the hallmarks of dry eye disease.

This article will detail the anatomy and function of the lacrimal glands and associated conditions and tests.

Anatomy

Each of your eyes has a lacrimal gland, which sits inside your eye socket, underneath your upper eyelid. The gland itself is small, measuring less than an inch. In an individual, the glands tend to be symmetrical (the one over the left eye similar in size to the one over the right eye).

The lacrimal gland is made up of two parts (called lobes). The larger lobe is the orbital lobe, and the smaller one is the palpebral lobe. A series of ducts, blood vessels, and nerves pass from the orbital lobe into the palpebral one. 

The lacrimal gland also has two accessory glands, called the glands of Krause and Wolfring. They are similar in structure to the main lacrimal gland, but they produce just 10% of the fluid the lacrimal gland does.

These glands and the fluid they make provide the eye with essential moisture and act as an important barrier, protecting the eye from foreign matter like dust, dirt, and pollen.

Function

The lacrimal gland produces the aqueous layer of the eye’s tear film. The aqueous layer of tears is made up of water, proteins, vitamins, electrolytes, and other substances. All these help lubricate the eye, wash away debris, and promote overall eye health.

Tears from the lacrimal gland get to the eye via tiny openings in the corners of the eye called puncta. When you blink, that fluid is spread across the eye.

The gland can also trigger tear production when there are stimuli to the eye (for example, a hair gets in your eye or a sharp, cold wind hits the surface of your eye). These are called reflex tears.

Associated Conditions

Problems with the lacrimal gland often result from inflammation. The inflammation can be caused by various factors, including the natural aging process, hormonal imbalances, infection, and autoimmune diseases.

Dacryoadenitis

Dacryoadenitis is inflammation of the lacrimal gland. It can occur in one eye or both eyes simultaneously. Acute inflammation (inflammation that is short-lived) tends to be caused by infections, such as the mumps, the Epstein-Barr virus, and herpes viruses. 

More chronic inflammation is typically caused by autoimmune disorders, including the inflammatory bowel disease Crohn's disease and Sjögren's syndrome (an immune system disorder that occurs when the body attacks the healthy cells that produce saliva and tears).

Acute dacryoadenitis is more prevalent in younger rather than older people, and chronic dacryoadenitis is seen more often in females, probably because more females than males have autoimmune diseases.

Symptoms of dacryoadenitis include:

• Pain in the eye
• Droopy eyelid
• Redness in the eye
• Problems opening the eye
• Blurred or double vision

Dry Eye Disease

When the lacrimal glands become chronically inflamed, they can’t make as many tears, which can contribute to a common disorder known as dry eye disease.

One in five adults has dry eyes, affecting more females than males and more older people than young.

Symptoms include:

• Pain or burning in the eye
• Blurred vision
• Eye redness that progresses throughout the day

While the vast majority of dry eye disease occurs because of problems with the eye’s meibomian gland, which supplies oil to the tear film (helping to keep the watery portion of tears from evaporating), about 10% of dry eye disease is related to lacrimal gland dysfunction.

Sarcoidosis

Sarcoidosis is an inflammatory disease that can affect any part of the body.

When it affects structures within the eye—and that can include the lacrimal gland—it is called ocular sarcoidosis. In people with systemic (or whole-body) sarcoidosis, 23%–56% will have eye involvement.

Common symptoms of ocular sarcoidosis are:

• Blurred vision
• Itchy, dry, burning eyes
• Pain in the eyes
• Floaters (spots or lines in your vision)
• Sensitivity to light

Tests

The first step your healthcare provider will take to diagnose a problem with your lacrimal gland(s) is ask about your family history and symptoms and perform a physical exam of your eyes.

Depending on what your healthcare provider suspects may be causing your eye problems, a variety of tests may be performed, including:

• A Schirmer test involves placing a special paper strip inside your lower eyelids to test your eye’s tear production. Not enough tears can be a signal your lacrimal gland is inflamed.
• Imaging tests, such as a computed tomography (CT) scan, may be ordered to visualize any lacrimal gland swelling/dysfunction.
• Nasal endoscopy may be performed. This involves using a thin, flexible tube with a camera at the end inserted into the nasal cavity to view the tear duct system.
• A biopsy may be done. If any lumps or masses are discovered, your doctor may surgically remove a portion to examine for cancerous cells.

Summary

Your lacrimal glands play an important role in your eye's production of tears. But when the gland is inflamed or infected, problems such as dry eyes or dacryoadenitis can occur. These problems are common and highly treatable with remedies like eye drops and, in rarer cases, surgery.

Your healthcare professional may refer you to an ophthalmologist (a specialist in eye diseases) who can properly diagnose problems with the lacrimal gland and set you on a proper treatment course.