Do you wonder from where do your tears originate? What are the uses of tears? From does your tear originate and what is the pathway for you tears? What are the problems associated with your tears and the glands?
Tears are composed of water, proteins, vitamins, electrolytes, and other substances. All of this helps to smooth the eyes, wash away debris and promote overall eye health.
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Anatomy of the eye
The eyes are in a protective bone cavity called the orbit. Six eye muscles in orbit are connected to the eye. These muscles move the eyes up, down, left and right, rotating the eyes.
The extraocular muscles are attached to the part of the eye called the sclera. This is a layer of thick tissue that covers almost the entire surface of the eyeball.
The surface of the eye and the inner surface of the eyelids are covered with a transparent film called the conjunctiva.
A layer of tear film moistens the front of the eye. Tears wet the eyes and are composed of three layers. The combination of these three layers is called the tear film. The mucous layer is formed by the conjunctiva.
The watery part of the tear fluid is made up of the lacrimal glands. The lacrimal duct of the eye is below the outer edge of the eyebrows of the eye socket (away from the nose). The meibomian glands produce oil, which is another part of the tear film. Tears flow out of the eye through the lacrimal duct.
Each eye has a lacrimal gland in the orbit below the upper eyelid. The glands themselves are small, less than an inch. In individuals, the glands are usually symmetrical (the glands above the left eye are similar in size to the glands above the right eye).
The lacrimal gland is made up of two parts also called as lobes. A series of tubes, blood vessels, and nerves pass through it.
The lacrimal gland also has two appendages called the Krause gland and the Wolfring gland. They are similar in structure to the main lacrimal glands, but produce only 10% of the fluid produced by the lacrimal glands.
These glands and the fluids they produce provide essential moisture for the eye and act as an important barrier to protect the eye. Eyes are protected from foreign matter such as dust, dirt and pollen.
The lacrimal glands produce a layer of tear film in the eye. The water layer of tears is composed of water, proteins, vitamins, electrolytes, and other substances. All of this helps to smooth the eyes, wash away debris and promote overall eye health.
Tears from the lacrimal duct enter the eye through a small opening in the corner of the eye called a puncta. After blinking, this liquid spreads throughout your eyes.
When a stimulus is applied to the eye, the glands can also cause tear production (for example, hair in the eye or a sharp, cold wind on the surface of the eye). These are called reflex tears.
Conditions associated with lacrimal gland
Lacrimal gland problems often result from inflammation. Inflammation can be caused by several factors, including the natural aging process, hormonal imbalances, infections, and autoimmune diseases.
- Dacryoadenitis
Dacryoadenitis is an inflammation of the lacrimal glands. It can occur in one or both eyes at the same time.
Acute inflammation (short-lived inflammation) is usually caused by infections such as mumps, Epstein-Barr virus, and herpesvirus. Chronic inflammation from is usually due to autoimmune diseases such as Crohn’s disease, which is an inflammatory bowel disease, and Sjogren’s syndrome (an immune system disorder that occurs when the body attacks healthy cells that produce saliva and tears).
Acute dacryoadenitis is more common in younger people than in the elderly, and chronic dacryoadenitis is more common in females. This is probably because women suffer from autoimmune diseases more than men.
The symptoms of dacryoadenitis are:
- Eye sore
- Eyelids drooping
- Redness of the eyes
- Problems in opening eyes
- Blurred vision or diplopia
- Dry eye disease
When the lacrimal duct becomes chronically inflamed, the lacrimal duct cannot shed so much tears and can contribute to a common condition known as dry eye.
One in five adults suffers from dry eye, with more females than males and older people than younger ones.
Symptoms are:
- Eye sore or burning sensation
- Blurred vision
- Red eye that progresses all day long
Most of the dry eye is due to problems with the meibomian glands that supplies oil to the tear film (which helps prevent the watery part of the tear from evaporating).
- Sarcoidosis
Sarcoidosis is an inflammatory condition that can affect any part of the body. When it affects the structure of the eye (which may include the lacrimal gland), it is called sarcoidosis of the eye. In patients with systemic (or systemic) sarcoidosis, 23% to 56% have their eyes involved.
Common symptoms of ocular sarcoidosis are:
- Blurred vision
- Itchy, dry, burning eyes
- Eye sore
- Floater (spot or line in view)
- Sensitivity to light
Testing and diagnosis
Depending on what your healthcare provider suspects, you can perform a variety of tests, including: The
Schirmer test inserts a special piece of paper into the lower eyelid to test for the formation of tears in the eyes. Not having enough tears may indicate that the lacrimal duct is inflamed.
Imaging studies such as computed tomography (CT) scans may be ordered to visualize lacrimal gland swelling / dysfunction.
Nasal endoscopy can be done. A thin, flexible tube with a camera at the end is inserted into the nasal cavity to see the lacrimal duct system. You can do a biopsy. If a lump or mass is found, the doctor may surgically remove part of it to check for cancer cells.
There is a small opening at the end of the eyelid near the nose. The upper and lower eyelids each have one of these openings called a punk.
These four openings or punctums act like small valves to remove tears from the eye. Every time you blink, tears are drained from your eyes.
When part or all of the punctum is blocked, tears overflow.
Because the punctum is small, even small particles of dirt or loose cells from the skin around the eyes can block them. Occasionally, the infection swells near the punctum and the punctum does not function properly. Any of these things can cause epiphora.
Function of tears
The precorneal tear film has several important functions that are essential for eye health. It maintains a moist environment on the surface of the eye and prevents epithelial cells from drying out and damaging, smooths the surface of the eyes and promotes eyelid movement, maintains a smooth refraction surface of the cornea and ensures that the eye have a correct vision, provides the avascular cornea with the nutrients and oxygen needed for its metabolism, contains enzymes (such as lysozyme), antibodies, and phagocytic cells that destroy bacteria and prevent the growth of corneal microcysts, removes waste products from the cornea, blink to remove foreign matter from the surface of the eye, protects the cornea and conjunctiva from atmospheric and chemical irritants, as well as temperature fluctuations, changes in the balance of the three layers of tear film can cause damage and cause symptoms such as dry eye.
After the tears leave the eye through the punctum, they flow down a small “tube” called the nasolacrimal duct.
This tube passes under the skin, through the bones of the face and into the nose. Usually, there is almost no tears, so the nose does not get very wet. If the punctum is open and functioning properly, it can also block the nasolacrimal duct. Not only does this cause problems with tear flow, it also usually causes other symptoms such as:
Swelling and redness in the area between the eyes and nose. Pain around the eyes and nose.
Treatment
If the test has showed that tears cannot pass through the punctum, your doctor may recommend that you put a warm, moist, clean washcloth on your eyes several times a day. This helps to open the clogged puncture and drain the liquid inside. Your doctor will tell you exactly how to do this and how many times a day it should be done.
Your doctor may recommend a procedure to open the obstructed lacrimal duct. He or she can do this correctly in the office by paralyzing the eyes with an anesthetic and then passing a special instrument through the puncture.
This may be necessary if the nasolacrimal duct appears to be infected. If you suspect that an infection is present, your doctor may prescribe antibiotics.
Sometimes infections have the side effect of permanently blocking the nasolacrimal duct and there is a problem for two reasons, one is, not only does the eye overflow with tears, but the clogged lacrimal duct continues to inflame. Fortunately, there are steps to resolve this issue.