Select Page

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

 Call a doctor toll free 1-877-917-1989 US/Canada;  international 650-949-6080; email: info@theralife.com

References

  1. The epidemiology of dry eye disease: report of the Epidemiology Subcommittee of the International Dry Eye WorkShop (2007) The ocular surface. 2007;5:93–107.
  2. Yu J, Asche CV, Fairchild CJ. The economic burden of dry eye disease in the United States: a decision tree analysis. Cornea. 2011;30:379–387.
  3. Abetz L, Rajagopalan K, Mertzanis P, et al. Development and validation of the impact of dry eye on everyday life (IDEEL) questionnaire, a patient-reported outcomes (PRO) measure for the assessment of the burden of dry eye on patients. Health and quality of life outcomes. 2011;9:111.
  4. Pouyeh B, Viteri E, Feuer W, et al. Impact of ocular surface symptoms on quality of life in a United States veterans affairs population. American journal of ophthalmology. 2012;153:1061–1066. e1063.
  5. Rajagopalan K, Abetz L, Mertzanis P, et al. Comparing the discriminative validity of two generic and one disease-specific health-related quality of life measures in a sample of patients with dry eye. Value Health. 2005;8:168–174.
  6. Methodologies to diagnose and monitor dry eye disease: report of the Diagnostic Methodology Subcommittee of the International Dry Eye WorkShop (2007) The ocular surface. 2007;5:108–152.
  7. Galor A, Feuer W, Lee DJ, et al. Ocular surface parameters in older male veterans. Investigative ophthalmology & visual science. 2013;54:1426–1433.
  8. Nichols KK, Nichols JJ, Mitchel GL. The lack of association between signs and symptoms in patients with dry eye disease. Cornea. 2004;23(8):762–70.
  9. Sullivan BD, Crews LA, Messmer EM, et al. Correlations between commonly used objective signs and symptoms for the diagnosis of dry eye disease: clinical implications. Acta Ophthalmol. 2014 Mar;92(2):161–6.
  10. Schein OD, Tielsch JM, Munõz B, et al. Relation between signs and symptoms of dry eye in the elderly. A population-based perspective. Ophthalmology. 1997 Sep;104(9):1395–401.
  11. Galor A, Felix ER, Feuer W, et al. Dry eye symptoms align more closely to non-ocular conditions than to tear film parameters. The British journal of ophthalmology. 2015;99:1126–1129.
  12. Galor A, Levitt RC, Felix ER, et al. Neuropathic ocular pain: an important yet underevaluated feature of dry eye. Eye. 2015;29:301–312.
  13. Rosenthal P, Baran I, Jacobs DS. Corneal pain without stain: is it real? Ocul. Surf. 2009;7(1):28–40.
  14. Chao C, Golebiowski B, Stapleton F. The role of corneal innervation in LASIK-induced neuropathic dry eye. Ocul Surf. 2014;12(1):32–45.
  15. Rosenthal P, Borsook D. The corneal pain system. Part I: the missing piece of the dry eye puzzle. Ocul Surf. 2012;10(1):2–14.
  16. Belmonte C, Acosta MC, Merayo-Lloves J, et al. What causes eye pain? Curr Ophthalmol Rep. 2015;3:111–121.
  17. Rahman M, Okamoto K, Thompson R, et al. Sensitization of trigeminal brainstem pathways in a model for tear deficient dry eye. Pain. 2015;156:942–950.
  18. Pain Taxonomy: International Assocation for the Study of Pain website. http://www.iasp-pain.org/Taxonomy?navItamNumber=576. Accessed June 15.
  19. Melzack R. The short-form McGill Pain Questionnaire. Pain. 1987;30:191–197.
  20. Melzack R. The McGill Pain Questionnaire: major properties and scoring methods. Pain. 1975;1:277–299.
  21. Bouhassira D, Attal N, Fermanian J, et al. Development and validation of the Neuropathic Pain Symptom Inventory. Pain. 2004;108:248–257.
  22. Chalmers RL, Begley CG, Caffery B. Validation of the 5-Item Dry Eye Questionnaire (DEQ-5): Discrimination across self-assessed severity and aqueous tear deficient dry eye diagnoses. Contact lens & anterior eye : the journal of the British Contact Lens Association. 2010;33:55–60.
  23. Schiffman RM, Christianson MD, Jacobsen G, et al. Reliability and validity of the Ocular Surface Disease Index. Archives of ophthalmology. 2000;118:615–621.
  24. Dworkin RH, Turk DC, Farrar JT, et al. Core outcome measures for chronic pain clinical trials: IMMPACT recommendations. Pain. 2005;113:9–19.
  25. Chang MY, Chen CH, Huang KF. A comparison of massage effects on labor pain using the McGill Pain Questionnaire. The journal of nursing research : JNR. 2006;14:190–197.
  26. Melvin EA, Jr., Jordan FR, Weiner RL, et al. Using peripheral stimulation to reduce the pain of C2-mediated occipital headaches: a preliminary report. Pain physician. 2007;10:453–460.
  27. Carroll IR, Younger JW, Mackey SC. Pain quality predicts lidocaine analgesia among patients with suspected neuropathic pain. Pain medicine. 2010;11:617–621.
  28. de Andrade DC, Ferreira KA, Nishimura CM, Yeng LT, Batista AF, de Sá K, Araujo J, Stump PR, Kaziyama HH, Galhardoni R, Fonoff ET, Ballester G, Zakka T, Bouhassira D, Teixeira MJ. Psychometric validation of the Portuguese version of the Neuropathic Pain Symptoms Inventory. Health Qual Life Outcomes. 2011;9:107.
  29. Sommer C, Richter H, Rogausch JP, et al. A modified score to identify and discriminate neuropathic pain: a study on the German version of the Neuropathic Pain Symptom Inventory (NPSI) BMC neurology. 2011;11:104.
  30. Attal N, Fermanian C, Fermanian J, Lanteri-Minet M, Alchaar H, Bouhassira D. Neuropathic pain: are there distinct subtypes depending on the aetiology or anatomical lesion? Pain. 2008;138:343–53.
  31. Zelman DC, Dukes E, Brandenburg N, et al. Identification of cut-points for mild, moderate and severe pain due to diabetic peripheral neuropathy. Pain. 2005;115:29–36.
  32. Siddall PJ, Cousins MJ, Otte A, et al. Pregabalin in central neuropathic pain associated with spinal cord injury: a placebo-controlled trial. Neurology. 2006;67:1792–1800.
  33. Onouchi K, Koga H, Yokoyama K, et al. An open-label, long-term study examining the safety and tolerability of pregabalin in Japanese patients with central neuropathic pain. Journal of pain research. 2014;7:439–447.
  34. Satoh J, Yagihashi S, Baba M, et al. Efficacy and safety evaluation of pregabalin treatment over 52 weeks in patients with diabetic neuropathic pain extended after a double-blind placebo-controlled trial. Journal of diabetes investigation. 2011;2:457–463.
  35. Rowbotham M, Harden N, Stacey B, et al. Gabapentin for the treatment of postherpetic neuralgia: a randomized controlled trial. Jama. 1998;280:1837–1842.
  36. Ferreira-Valente MA, Pais-Ribeiro JL, Jensen MP. Validity of four pain intensity rating scales. Pain. 2011;152:2399–2404.
  37. Jensen MP, Turner JA, Romano JM. What is the maximum number of levels needed in pain intensity measurement? Pain. 1994;58:387–392.
  38. Caraceni A, Cherny N, Fainsinger R, et al. Pain measurement tools and methods in clinical research in palliative care: recommendations of an Expert Working Group of the European Association of Palliative Care. J Pain Symptom Manage. 2002;23:239–255.
  39. Farrar JT, Young JP, Jr, LaMoreaux L, et al. Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain. 2001;94:149–158.
  40. Paice JA, Cohen FL. Validity of a verbally administered numeric rating scale to measure cancer pain intensity. Cancer Nurs. 1997;20:88–93.
  41. Galor A, Zlotcavitch L, Walter SD, et al. Dry eye symptom severity and persistence are associated with symptoms of neuropathic pain. The British journal of ophthalmology. 2015;99:665–668.
  42. Galor A, Batawi H, Felix ER, et al. Incomplete response to artificial tears is associated with features of neuropathic ocular pain. The British journal of ophthalmology. 2015
  43. Masson EA, Hunt L, Gem JM, et al. A novel approach to the diagnosis and assessment of symptomatic diabetic neuropathy. Pain. 1989;38:25–28.
  44. Dubuisson D, Melzack R. Classification of clinical pain descriptions by multiple group discriminant analysis. Experimental neurology. 1976;51:480–487.
  45. Grushka M, Sessle BJ, Miller R. Pain and personality profiles in burning mouth syndrome. Pain. 1987;28(2):155–67.
  46. Charleston Lt. Burning mouth syndrome: a review of recent literature. Curr Pain Headache Rep. 2013;17(6):336.
  47. Erdelyi B, Kraak R, Zhivov A, et al. In vivo confocal laser scanning microscopy of the cornea in dry eye. Graefe’s archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2007;245:39–44.
  48. De Paiva CS, Pflugfelder SC. Corneal epitheliopathy of dry eye induces hyperesthesia to mechanical air jet stimulation. American journal of ophthalmology. 2004;137:109–115.
  49. Situ P, Simpson TL, Fonn D, et al. Conjunctival and corneal pneumatic sensitivity is associated with signs and symptoms of ocular dryness. Investigative ophthalmology & visual science. 2008;49:2971–2976.
  50. Tuisku IS, Konttinen YT, Konttinen LM, et al. Alterations in corneal sensitivity and nerve morphology in patients with primary Sjogren’s syndrome. Experimental eye research. 2008;86:879–885.
  51. Benitez-Del-Castillo JM, Acosta MC, Wassfi MA, et al. Relation between corneal innervation with confocal microscopy and corneal sensitivity with noncontact esthesiometry in patients with dry eye. Investigative ophthalmology & visual science. 2007;48:173–181.
  52. Bourcier T, Acosta MC, Borderie V, et al. Decreased corneal sensitivity in patients with dry eye. Investigative ophthalmology & visual science. 2005;46:2341–2345.
  53. Lambiase A, Micera A, Sacchetti M, et al. Alterations of tear neuromediators in dry eye disease. Archives of ophthalmology. 2011;129:981–986.
  54. Vehof J, Kozareva D, Hysi PG, et al. Relationship between dry eye symptoms and pain sensitivity. JAMA Ophthalmology. 2013;131(10):1304–1308.
  55. Vehof J, Kozareva D, Hysi PG, et al. Prevalance and risk factors of dry eye disease in a British female cohort. Br J Ophthalmol. 2014;98:1712–1717.

 

Subscribe To Our Newsletter

Join our mailing list to receive the latest news and updates from our team.

You have Successfully Subscribed!

Pin It on Pinterest