Here is the improved version of the blog post with the formatting and sources preserved:
Dry eyes can be a frustrating and complex condition, often resulting from a combination of factors that disrupt the delicate balance of the tear film. Understanding the underlying causes of dry eyes is crucial for developing an effective treatment plan and preventing further damage to the ocular surface.
Dry eyes can trigger inflammation, which in turn exacerbates dryness, creating a vicious cycle that worsens symptoms over time.1 By identifying and addressing the root causes of your dry eyes, you can break this cycle and protect your eyes from long-term harm.
The Three Layers of the Tear Film
Dry eyes typically occur when tear production is insufficient or when tears evaporate too quickly. To better understand the development of dry eyes, it’s essential to know about the three layers that make up the tear film:
1. The inner mucus layer: This layer lies directly on the cornea and forms the foundation of the tear film, helping it spread evenly and adhere to the ocular surface.2 Disruptions in this layer can lead to both dry and watery eyes.
2. The middle aqueous layer: As the main fluid component of the tear film, a lack of aqueous tear production can quickly lead to dry eyes. However, this is rarely the sole cause of the condition.3
3. The outer lipid layer: Produced by the meibomian glands along the eyelid margins, this layer prevents rapid tear evaporation. Inflammation of the meibomian glands can alter the composition of the lipid layer, destabilizing the tear film. A thin or dysfunctional lipid layer is the most common cause of dry eyes.4
Risk Factors for Dry Eyes
Several risk factors can affect the tear film layers and contribute to the development of dry eyes, including:
- Medical conditions: Diabetes, autoimmune diseases, and hypothyroidism can increase the risk of dry eyes.5,6,7
- Allergies: An overactive immune response to allergens can lead to inflammation and dry eyes.8
- Medications: Antidepressants, cholesterol-lowering drugs, beta-blockers, neuroleptics, and antihistamines can cause dry eyes as a side effect.9
- Age: Tear production decreases with age, and older individuals are more likely to take medications that can cause dry eyes.10
- Hormonal changes: Women are more prone to dry eyes, especially during pregnancy or menopause.11
- Vitamin A deficiency: Essential for eye health, a lack of vitamin A can lead to dry eyes.12
- Incomplete eyelid closure: If the eyelids don’t close completely, such as after surgery, dry eyes can develop due to increased tear evaporation.13
- Uncorrected vision problems: People with poor vision may stare and blink less frequently, leading to inadequate eye moisture.14
- Refractive eye surgery: Dry eyes are a common side effect of refractive surgery, which can be temporary or permanent.15
- Contact lens wear: Contact lenses can damage the lipid layer of the tear film, increasing the risk of dry eyes, especially with prolonged daily wear.16
Environmental Factors That Contribute to Dry Eyes
As mentioned earlier, dry eyes often result from a combination of factors. Environmental conditions can irritate the eyes or promote tear evaporation, exacerbating dry eye symptoms.17
- Dry air from heating or air conditioning can cause tears to evaporate too quickly.
- Air pollution and fumes can irritate the eyes and indirectly trigger dry eyes.
- Direct sunlight or UV exposure can damage the cornea, leading to dry eyes.18
- Cosmetics, such as eye makeup, foundation, or face cream, can disrupt the tear film if they enter the eye.
- Prolonged screen time can reduce blink rate, leading to inadequate eye moisturization. While the average person blinks around 17 times per minute, this can drop to just a few blinks per minute when working at a computer. It’s even worse when playing computer games.19,20
A Multifaceted Approach to Managing Dry Eyes
Dry eyes often result from a combination of factors that lead to increased tear evaporation, most commonly due to an unstable lipid layer of the tear film. Inflammation plays a crucial role in this process, as it can both cause and be aggravated by dry eyes.
Given the diverse causes of dry eyes, there are several promising treatment options, such as artificial tears. For those who work at a computer, using software like Blinkr to increase blink rate can also provide significant relief.
By understanding the underlying causes of your dry eyes and working with your eye care professional to develop a personalized treatment plan, you can effectively manage your symptoms and maintain long-term ocular health.
References
1. Pflugfelder SC, de Paiva CS. The Pathophysiology of Dry Eye Disease. Ophthalmology. 2017;124(11):S4-S13. doi:10.1016/j.ophtha.2017.07.010
2. Zhang X, M VJ, Qu Y, et al. Dry Eye Management: Targeting the Ocular Surface Microenvironment. International Journal of Molecular Sciences. 2017;18(7):1398. doi:10.3390/ijms18071398
3. Lemp MA, Crews LA, Bron AJ, Foulks GN, Sullivan BD. Distribution of Aqueous-Deficient and Evaporative Dry Eye in a Clinic-Based Patient Cohort. Cornea. 2012;31(5):472-478. doi:10.1097/ICO.0b013e318225415a
4. Tong L, Chaurasia SS, Mehta JS, Beuerman RW. Screening for Meibomian Gland Disease: Its Relation to Dry Eye Subtypes and Symptoms in a Tertiary Referral Clinic in Singapore. Investigative Opthalmology & Visual Science. 2010;51(7):3449. doi:10.1167/iovs.09-4445
5. Zhang X, Zhao L, Deng S, Sun X, Wang N. Dry Eye Syndrome in Patients with Diabetes Mellitus: Prevalence, Etiology, and Clinical Characteristics. Journal of Ophthalmology. 2016;2016:1-7. doi:10.1155/2016/8201053
6. Akpek EK, Klimava A, Thorne JE, Martin D, Lekhanont K, Ostrovsky A. Evaluation of Patients With Dry Eye for Presence of Underlying Sjögren Syndrome. Cornea. 2009;28(5):493-497. doi:10.1097/ICO.0b013e31818d3846
7. Kan E, Kılıçkan E, Ecemiş G, Beyazyildiz E, Çolak R. Presence of Dry Eye in Patients with Hashimoto’s Thyroiditis. Journal of Ophthalmology. 2014;2014:1-4. doi:10.1155/2014/754923
8. Villani E, Rabbiolo G, Nucci P. Ocular allergy as a risk factor for dry eye in adults and children. Current Opinion in Allergy and Clinical Immunology. 2018;18(5):398-403. doi:10.1097/ACI.0000000000000471
9. Fraunfelder FT, Sciubba JJ, Mathers WD. The Role of Medications in Causing Dry Eye. Journal of Ophthalmology. 2012;2012:1-8. doi:10.1155/2012/285851
10. Sharma A, Hindman HB. Aging: A Predisposition to Dry Eyes. Journal of Ophthalmology. 2014;2014:1-8. doi:10.1155/2014/781683
11. Schaumberg DA. Hormone Replacement Therapy and Dry Eye Syndrome. JAMA. 2001;286(17):2114. doi:10.1001/jama.286.17.2114
12. Wardeh R, Besgen V, Sekundo W. Therapy-resistant dry itchy eyes. Journal of Ophthalmic Inflammation and Infection. 2019;9(1):13. doi:10.1186/s12348-019-0178-7
13. Messmer EM. The Pathophysiology, Diagnosis, and Treatment of Dry Eye Disease. Deutsches Aerzteblatt Online. January 2015. doi:10.3238/arztebl.2015.0071
14. Evinger C, Bao J-B, Powers AS, et al. Dry eye, blinking, and blepharospasm. Movement Disorders. 2002;17(S2):S75-S78. doi:10.1002/mds.10065
15. Shtein RM. Post-LASIK dry eye. Expert Review of Ophthalmology. 2011;6(5):575-582. doi:10.1586/eop.11.56
16. Kojima T. Contact Lens-Associated Dry Eye Disease: Recent Advances Worldwide and in Japan. Investigative Opthalmology & Visual Science. 2018;59(14):DES102. doi:10.1167/iovs.17-23685
17. Dry Eye. https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/dry-eye. Accessed October 25, 2019.
18. Behar-Cohen F, Baillet, de Ayguavives, et al. Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear. Clinical Ophthalmology. December 2013:87. doi:10.2147/OPTH.S46189
19. Bentivoglio AR, Bressman SB, Cassetta E, Carretta D, Tonali P, Albanese A. Analysis of blink rate patterns in normal subjects. Movement Disorders. 1997;12(6):1028-1034. doi:10.1002/mds.870120629
20. Freudenthaler N, Neuf H, Kadner G, Schlote T. Characteristics of spontaneous eyeblink activity during video display terminal use in healthy volunteers. Graefe’s Archive for Clinical and Experimental Ophthalmology. 2003;241(11):914-920. doi:10.1007/s00417-003-0786-6