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People who suffer from dry eyes have various complaints, including blurred vision, irritation, and pain. The pain is often a sharp, transient, stabbing pain, known as “nociceptive pain.” The more chronic eye pain is called “neuropathic pain”. Neuropathic pain is secondary to changes in the somatosensory pathway.

What are Dry Eyes

Our eyes need balanced tears to stay healthy and comfortable. If your eyes do not produce enough balanced tears, you get a dry eye. Dry eye is also when your eyes do not make the right type of tears or tear film. 

Dry eyes can happen when tears evaporate too quickly (Evaporative dry eyes) or if the eyes produce fewer tears. It can affect one or both eyes, resulting in a lot of inflammation.

The eyes produce tears all day long – when we yawn or experience emotion. Healthy eyes are frequently covered with a fluid known as a tear film. It is designed to remain stable between each blink. This prevents the eyes from becoming dry and clear vision.

If the tear glands produce fewer tears, the tear film can become unstable. It can break down quickly, creating dry spots on the surface of the eyes. These dry spots show up on the fluorescence dye test.

Tears are made of water, fatty oils, protein, electrolytes, substances to fight off bacteria, and growth factors. The mixture helps keep the surface of the eyes smooth and clear so that we can see correctly.

Common Causes of Dry Eyes

Dry eye syndrome can occur at any age and in otherwise healthy people. It is more common with older people when less tear is produced. It is also more common in women than in men.

Dry eyes can result from:

  • an imbalance in the tear mixture so that it evaporates too fast
  • insufficient tear production for good eye health

Other causes include eyelid problems, some drugs, and environmental factors.

Imbalance of the tear – Blepharitis /Meibomian Gland Dysfunction (MGD)

The tear film has three layers, oil, water, and mucus. Problems with any of these can lead to dry eye symptoms.

The top layer, oil, comes from the eyelids’ edges, where the meibomian glands produce lipids or fatty oils. The oil smooths the tear surface and slows down the rate of evaporation. Faulty oil levels can cause the tears to evaporate too quickly – which is the major problem in meibomian gland dysfunction. 

Inflammation along the edge of the eyelids is known as blepharitis. Rosacea and some other skin disorders can cause the meibomian glands to become blocked, making dry eyes more severe.

The middle layer is the thickest, consisting of water and salt. The lacrimal glands, or tear glands, produce this layer. They cleanse the eyes and wash away particles and irritants. Problems with this layer can lead to film instability. If the water layer is too thin, the oil and mucus layers may touch each other, resulting in a stringy discharge, a hallmark sign of dry eyes.

The inner layer, mucus, enables the tears to spread evenly over the eyes. A malfunction can lead to dry patches on the cornea, the front surface of the eye.

What causes eye pain?

Eye pain can be caused by several conditions and factors. These can include:

  • A bacterial or viral infection in the eye. Often causing pink eye called conjunctivitis
  • A bacterial or viral infection that spreads from an area of one’s own body (such as the nose or sinuses) to the eyes.
  • Dirty contact lenses, poorly fitting contact lenses, or decorative contact lenses.
  • Allergic reactions to pollen or animals.
  • Irritation from cigarette smoke, air pollutants, chlorine in a swimming pool, or other toxins.
  • Swelling or inflammation of the eye- Iritis, Uveitis.
  • An increase in eye pressure caused by Glaucoma

What are some common conditions and symptoms associated with eye pain?

Common conditions and symptoms linked to eye pain can include:

  • Cellulitis: Inflammation of tissue beneath the surface of the skin.
  • Perceptual: Affects the skin of the eyelid; found predominantly in young children.
  • Orbital: Affects the eye socket, causing the eye or eyelid to swell so that proper eye movement becomes difficult.
  • Conjunctivitis (pink eye): An infection or allergic reaction in the conjunctiva, which is the mucous membranes that line the inner eyelids and surface of the eyeballs.
  • Viral: A most common type of pink eye. Causes burning, red, watery eyes. It is highly contagious, particularly in school settings or crowds of people. Viral eye infections should go away by themselves in 2 weeks. 
  • Bacterial: Maybe highly contagious. Causes sore, red eyes with sticky pus.
  • Allergic: Stems from an allergic reaction to an airborne allergen that is not contagious. Causes itching, red, watery eyes.
  • Corneal Abrasion: A scrape or scratch on the cornea. Happens often in severe chronic dry eyes. 
  • Corneal laceration: A cut on the cornea, usually caused by a sharp object flying into the eye, or something hitting the eye with force. A rip may tear partially or entirely through the eyeball.
  • Corneal ulcer: An open sore on the cornea, caused by either infection, severe dry eye, or other conditions.
  • Dry Eye: Lack of moisture in the eyes, leading to the sensation of a foreign object in the eye, sensitivity to light, tearing up, and sometimes redness. Causes include wearing contact lenses, using certain drugs (such as antihistamines, beta-blockers, opiates, and tricyclic antidepressants), disease, injury, or environmental factors (such as air conditioning).
  • Fuch’s Dystrophy: An eye disease in which cells in the upper layers of the cornea die off, causing fluid buildup, swollen and puffy eyes, and blurred vision.
  • Keratitis: An infection of the cornea (the clear dome-shaped front of the eye) resulting from injury or use of contact lenses. The condition can be caused by a fungus, bacteria, herpes virus, amoeba, or intense exposure to ultraviolet radiation (snow blindness or welder’s arc eye). If left untreated, blindness can occur.
  • Glaucoma: Fluid buildup in the front of the eye, causing pressure that damages the optic nerve. This is the leading cause of blindness in people over 60 years of age.
  • Primary open-angle Glaucoma: Fluid does not drain from the eye naturally. This kind of Glaucoma rarely causes eye pain.
  • Angle-closure Glaucoma: The iris (the colored part of the eye) is very close to the drainage angle of the eye, which can block proper drainage. Angle-closure Glaucoma causes pain more often than other types of Glaucoma.
  • Hyphema: Blood collects between the cornea and iris, usually due to an injury that causes a tear to the iris or pupil of the eye.
  • Microvascular cranial nerve palsy: Blood flow to the nerves that control eye movement is blocked. As a result, normal eye movement is not possible, and double vision may result. It is found frequently in people with diabetes or high blood pressure.
  • Optic neuritis: Swelling of the optic nerve, the nerve that carries light signals to the back of the eye then to the brain for the processing of visual images. Optic neuritis may be an autoimmune disease and is often found in people who have had virus-based diseases such as mumps, measles, flu, or multiple sclerosis.
  • Uveitis: Inflammation of the middle layer of the eyeball (the uvea). Damage to eye tissue can be serious, leading to blindness.

What causes Eye Pain in Dry Eyes?

Research studies showed that environmental factors and inflammation can cause ocular surface damage, which triggers alterations in peripheral corneal nerves. The alterations cause dry eye sensations, which lower the activation threshold of the nerve fibers. If ocular surface damage persists, shifts occur in the central nervous system (CNS), producing “central sensitization.” The hallmark of central sensitization is that pain continues to happen, even after the damage has resolved. This is commonly seen in dry eye patients where they continue to be symptomatic, but no ocular surface findings are observed. The process of central sensitization may initially be reversible, but it often becomes permanent. 

Traditional dry eye therapy includes topical and oral medications to improve the health of the eye. Central sensitization causes eye pain even when ocular surface is normal. 

Neuropathic Ocular Pain: An Important Yet Underevaluated Feature of Dry Eye 

How Can TheraLife Help?

 TheraLife Eye capsules are designed to treat dry eyes from inside out.  It works to improve deliver blood and nutrients to the eye as well as carrying out debri, unwanted fluids out of the eye.  TheraLife Eye capsules are strongly anti-inflammatory. 

To learn more: click here

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