Eyes is one of the most essential organ in the body. It makes it possible for us to see and appreciate the beauty of our surroundings. In today's era, where the whole world is at the fingertips, thanks to the internet and computers, the value of eyes and vision have become priceless. However, the extreme dependency on the digital world has its own set of effects on the eye, and one of them is 'dry eyes.'
Table of Contents
What is dry eye?
Let's understand the concept of a dry eye with a easy comparison between a machine and an eye. A machine requires oil for lubrication and smooth running. Similarly, the eyes need tears as a lubricant for proper functioning.
Dry eye disease occurs when the tears are not able to lubricate the eyes properly. This condition earlier used to be prevalent during the latter part of life; however, with the increased use of digital devices, the younger population is also experiencing dry eyes1Aggarwal, S., & Galor, A. (2018, December 19). 'What's new in dry eye disease diagnosis? Current advances and challenges' Source-PubMed
To understand why dry eyes are caused, it is first essential to know how tears are produced in the eye.
Understanding Tears And Tear Film
What are Tears Made of and Why do we need to have tears?
Tears play a significant role in ensuring the overall health of the front portion of the eye. It consists of water, salts, oil, antibodies, enzymes, which protect the eye. The front structures of the eye (cornea and conjunctiva) need to remain wet for normal functioning, and hence it is understandable why tears are essential.
What is the role of tear film in producing tears?
The layers displayed below constitute a tear film. Each layer has a specific role which is as follows:-
Click on the image below to know the role of an individual layer in producing tears:-
- Producing Tears
Aqueous layer comprises of water and salts (mainly) and is an essential layer that helps in keeping the eyes moist and well lubricated. It is produced by the lacrimal gland located on either side of the temple. It also helps in protecting your eye from any foreign particles.
- preventing Tear's evaporation from the eye
An oil or lipid layer is produced by the meibomian glands located in the eyelids. This lipid layer forms the tear film's outermost layer, protecting the aqueous layer and plays a significant role in preventing the tears' evaporation
- distributing the tears evenly in the eye.
Mucin layer is the innermost layer of the tear film produced by the goblet cells of the conjunctiva. This layer remains in contact with the corneal and conjunctival epithelial cells and distributes the tears evenly on the eye's surface.
What causes dry eyes?
Dry eyes commonly occur due to the following reasons:-
1. Instability In The Tear Film
The balance between the three layers (Lipid layer, Aqueous Layer and Mucin Layer) of the tear film usually keeps the surface of the eyes lubricated and moist. Hence any issue with any of these three layers can cause increased evaporation of tears leading to dry eyes. In such a case, even though the production of tears may be normal, you can still have dry eyes because the tears produced are not stable enough to coat the eye surface.
What Causes tear film dysfunction which eventually leads to Dry Eyes?
Tear film dysfunction occurs when the tear film's three layers (Lipid layer, Aqueous Layer and Mucin Layer) do not work properly due to an underlying disease.
- Lipid layer deficiency occurs in individuals suffering from Blepharitis or in a condition where the Meibomian glands' ducts are blocked. This leads to dry eyes
Quick Note - What is a Meibomian Gland?
Meibomian glands secrete an oily substance that helps prevent the evaporation of tears from the eyes.
- Aqueous layer deficiency occurs in individuals suffering from autoimmune conditions like Sjogren's syndrome, rheumatoid arthritis, collagen vascular disease, lupus, etc. The lacrimal gland gets affected in all these diseases due to which the tear production gets affected, which eventually leads to dry eyes3M. Ramos-Casals, P. B., Q. Zhang, X. W., KF. Farrand, M. F., F. Stapleton, M. A., JP. Craig, K. N., MS. Liew, M. Z., . . . C. Baudouin, P. A. (2018, March 20). 'Factors associated with severe dry eye in primary Sjögren's syndrome diagnosed patients' Source
Quick Note - What is a Lacrimal Gland?
Lacrimal glands help in secreting the tears in the eye.
- Mucin deficiency is seen in Steven Johnsons syndrome, Ocular pemphigoid, chemical injury, vitamin A deficiency and in chronic allergic eye disease, where the conjunctiva is mainly affected. A deficiency in mucin leads to dry eyes.
2. Insufficient production of tears
The second reason for having a dry eye is a decrease in the production of the tears. Following are the causes for decreased tear production5Golden, M. I. (2020, July 02). 'Dry Eye Syndrome' Source-PubMed:-
- Autoimmune Disorders
As discussed before, any disease which affects the lacrimal gland can affect tear film production. Certain autoimmune diseases like Sjogren's syndrome, rheumatoid arthritis(RA), systemic lupus erythematosus (SLE), scleroderma, graft vs. host disease, sarcoidosis can destroy the lacrimal gland with the body turning against its own tissues; hence the tear production is reduced
Autoimmune disorder is a medical condition in which the body's immune system can not differentiate between a foreign body and its own cells. As a result, the immune systems act against its own cells and thereby harm the human body.
As the age increases, in some individuals, the lacrimal gland loses its ability to produce tears due to the loss of cells (as a result of aging). Hence, tear production reduces gradually.
Medications like anti allergic, anti depressants decongestants, hormone replacement therapy, and drugs for hypertension, Parkinsonism and oral contraceptive pills can cause dry eyes as side effects
- Damage to Corneal Nerves
Any injury or damage to corneal nerves is known to reduce tear production. Refractive surgeries like LASIK and chronic contact lens use can cause damage to corneal nerves. However, symptoms of dry eyes related to the damage of corneal nerves are usually short-lived.
The corneal nerves play an important role in blink reflex and, hence, in tears' production and secretion.
- Radiation Therapy
Radiation therapy is known to affect the cells of the lacrimal gland and thus results in reduced tear production, which eventually leads to dry eyes6SW;, K. S. (2020, January 13). 'Effects of radiation therapy on the meibomian glands and dry eye in patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma' Source-PubMed
What are the Symptoms of Dry Eyes?
Am i at risk of developing dry eyes?
You are more likely to develop dry eyes if you are or have:-
- Older than 50 Years of Age
The volume of tear production reduces as you grow older. As we grow older, like any other cell in the body, the goblet cells and cells of the lacrimal glands lose their ability to regenerate the damaged cell. Hence, it leads to dry eyes8De Paiva, C. S. (2017). 'Effects of Aging in Dry Eye' Source-PubMed
Menopause, hormonal changes, and the use of birth control pills can directly affect tear production9Peck, T., Olsakovsky, L., & Aggarwal, S. (2017). 'Dry Eye Syndrome in Menopause and Perimenopausal Age Group' Source-PubMed
- Vitamin A and Omega-3 Fatty Acid Deficiency
If your food is deficient in vitamin A or omega-3 fatty acids. Vitamin A is found abundantly in the liver, carrots, and broccoli. Omega-3 fatty acids are found in fish, walnuts and vegetable oils10I, J. (2013, December). 'Diet, nutraceuticals and the tear film' Source-PubMed
- Contact Lenses
Wearing contact lenses for a long duration or having a refractive surgery history can lead to dry eyes11T;, K. (2018, November). 'Contact Lens-Associated Dry Eye Disease: Recent Advances Worldwide and in Japan' Source-PubMed
- Thyroid Disease
Thyroid Disease can push the eye forward and result in dryness of the eye12Alanazi, S. A., Alomran, A. A., Abusharha, A., Fagehi, R., Al-Johani, N. J., El-Hiti, G. A., & Masmali, A. M. (2019, June 28). 'An assessment of the ocular tear film in patients with thyroid disorders' Source-PubMed
- Chronic Eye Allergies
- Immunodeficient Conditions
Immunodeficient conditions like lupus and rheumatoid arthritis can result in dryness of the eyes14Ma, W., Wang, G., Li, X., Wu, H., Liu, Z., Dong, N., & Li, C. (2020, August 08). 'Study of Factors Influencing Dry Eye in Rheumatoid Arthritis' Source-PubMed
- Exposure Keratitis
What Will Happen If I Don't Treat The Dry Eye?
People who have dry eyes may experience the following complications if not treated on time:-
- Eye Infections
The antibodies present in the tear film protect the eye surfaces from infections. Without a sufficient volume of tears, the risk of eye infection increases.
- Ocular surface damage and Loss of Vision
If dry eyes are left untreated, severe dry eyes can cause eye inflammation, injury to the corneal surface leading to ulcers and eventually scarring leading to loss of vision
- Decreased quality of life
Dry eyes can make it challenging to keep the eyes open for long periods, thus hindering daily activities such as reading, watching television etc.
How Does an Ophthalmologist Diagnose Dry Eyes?
After a series of tests and procedures, ophthalmologists evaluate the rate of production, rate of evaporation of the tear film, and check the quality of the tear film to confirm the presence of dry eyes. 16Golden, M. I. (2020, July 02). 'The pathophysiology, diagnosis, and treatment of dry eye disease' Source-PubMed.
- Brief Examination of the Eye
A brief examination of the eyes does the first level of check. The patient's complaints and general overall health issues help the ophthalmologist diagnose and find the cause of dry eyes.
- Schirmer's Strip Or Phenol Red Thread Test
After conducting the physical examination of eye, your ophthalmologist may proceed to measure the volume of tears using the Schirmer's strips or phenol red thread test.
In this test, Schirmer's strips or thread dipped in phenol red are placed inside the lower eyelids. The wetness of the strip or the thread, post-test is checked to ascertain the volume of tears
- Dye Test
Tests to evaluate the quality of tear film are done using special dyes like fluorescein and rose bengal. The doctor will ask you to blink and then look for spots of evaporation of stains on the cornea and measures how long it takes before the tears evaporate
- Tear Osmolarity Test
A tear osmolarity test evaluates the composition of salts and water in tears. In short, it evaluates the aqueous layer of the tear film.
How can my dry eyes be treated?
Treatment depends on how severe the condition is17Messmer, E. M. (2015, January 30). 'The pathophysiology, diagnosis, and treatment of dry eye disease' Source-PubMed. Non-surgical treatment will be more than sufficient for majority of the patients suffering from occasional or mild dry eye symptoms. However, if symptoms are persistent and are more severe, then surgical options have to be explored.
Medical/Non Surgical Treatment
Antibiotics are given if the dry eye is caused due to eyelid infections.
Steroids are given if dry eyes is caused due to an inflammation in the eye.
Lubricating Eye Drops
Lubricating eye drops are prescribed to compensate for the loss of tear.
Tear-stimulating drugs such as Cyclosporin A may be prescribed depending upon the symptoms.
Warm Compresses and Lid Massage
Warm compress and lid massage are recommended when the dry eye is caused by the blocked meibomian glands(in the eye lids)
A newer method, a thermal pulsation device, is now being used to relieve Meibomian ducts' clogging. However, it is still unclear if this method is more advantageous than traditional warm compresses18SC;, S. C. (2017, January). 'Effectiveness of an Eyelid Thermal Pulsation Procedure to Treat Recalcitrant Dry Eye Symptoms After Laser Vision Correction' Source-PubMed.
Surgical treatment- is considered for cases where the medications fail or in patients experiencing severe dry eyes with the involvement of cornea and conjunctiva.
Punctums are the small holes situated in both the upper and lower eyelids, which drain the tears into the nose. These can be occluded either temporarily or permanently depending upon the severity of dry eye.
Occlusion of the punctum prevents the tears' drainage, thus letting the tears stay in the eye for a longer period of time and eventually helps keep the eyes wet.
Punctual plugs are small silicone plugs that are inserted in the punctum. This procedure is reversible, which means, if required, the plugs can be removed.
When the punctal plugs get repeatedly extruded, tear ducts can be plugged or destroyed with a procedure that uses heat called thermal cautery. This procedure, unlike the punctal plugs, is irreversible19Emii O, Murat D, Eri H, Asako Y, Rie A,Yukako T, Yoko O, Kazuo T, Eiki G. (2011, January). 'Surgical punctal occlusion with a high heat-energy releasing cautery device for severe dry eye with recurrent punctal plug extrusion' Source.
Since the punctum is located in the eyelids, eyelids' position plays a significant role in causing dry eyes. Conditions like ectropion (outward turning of eyelids) or entropion (inward turning of eyelids) needs to be rectified to treat the dry eyes. These conditions have to be addressed by an oculoplastic surgeon.
Special Contact Lenses
Special contact lenses like bandage contact lenses and scleral lenses are used in severely dry eyes to protect the eye's surface and trap the moisture.
Amniotic Membrane Graft
Amniotic membrane graft is done in cases of severe dry eyes where there is an involvement of cornea, which can cause loss of vision20Shafer, B. (2019, June). 'The use of self-retained, cryopreserved amniotic membrane for the treatment of Sjögren syndrome: a case series.' Source.
Salivary Gland Transplantation21Wakamatsu TH;SantʼAnna AEBPP;Cristovam PC;Alves VAF;Wakamatsu A;Gomes JAP;. (2017, November). 'Minor Salivary Gland Transplantation for Severe Dry Eyes.' Source
Salivary gland transplantation is considered as an option in extreme cases where even the amniotic membrane graft fails
How to prevent dry eyes?
You can avoid suffering from dry eyes if you take care of the following points:-
Avoid Direct Contact with Air
Avoid blowing air directly into the eyes while using hairdryers, air coolers, car heaters, or fans.
Moisture in Air
Add moisture to the air by using a humidifier, especially in winter.
Wear wraparound sunglasses or other protective eyewear to protect the eyes from wind, smoke, or dry and cold air.
Take regular breaks in between your work, especially when it requires you to work on a laptop, PC, mobile, tab or any other digital device.
- It's advised to follow the 'RULE OF 20'. The rule states that every 20 minutes, take a break for 20 seconds to look at an object placed 20 feet.
Alternatively, you can close your eyes or repeatedly blink for a few minutes. This can be repeated every 20 minutes
Extreme Air Temperature
The environment we live in also affects the condition of our eyes. The cold air at high altitudes, hot air in desert areas, and dry air in airplanes can worsen the dry eye disease. If you live in such an environment, then blinking frequently or using moisturizing eye drops can retain the eyes' wetness and prevent dry eyes.
While doing activities that require focusing, the object of interest, such as computer, book, TV, Kindle, should be placed lower than the eye. Placement of the screen above the eye level causes the eye to open wide; hence, the tears will evaporate.
The screen's brightness should be adjusted to a minimum tolerable level to avoid discomfort to the eye.
Smoking is known to worsen the dry eye symptoms and therefore it is better to quit smoking or avoid smoke22Xu, L., Zhang, W., Zhu, X., Suo, T., Fan, X., & Fu, Y. (2016, October 18). 'Smoking and the risk of dry eye: A Meta-analysis.' Source
We know that being diagnosed with Dry Eyes can be daunting however following the approach as shared in this article, will surely help improve your quality of life.
- 1Aggarwal, S., & Galor, A. (2018, December 19). ‘
What's new in dry eye disease diagnosis? Current advances and challenges’.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6305205/
- 2Vicnesh, Jahmunah & Oh, Shu Lih & Koh, Joel En Wei & Ciaccio, Edward & Chua, Chua & Tong, Louis & Acharya, U Rajendra. (2020).
Thoughts concerning the application of thermogram images for automated diagnosis of dry eye - A review.
Retrieved October 17, 2020, Infrared Physics & Technology. 10.1016/j.infrared.2020.103271.
- 3Golden, M. I. (2020, July 02).
Dry Eye Syndrome.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/books/NBK470411/
- 4M. Ramos-Casals, P. B., Q. Zhang, X. W., KF. Farrand, M. F., F. Stapleton, M. A., JP. Craig, K. N., MS. Liew, M. Z., . . . C. Baudouin, P. A. (2018, March 20).
Factors associated with severe dry eye in primary Sjögren's syndrome diagnosed patients.
Retrieved October 17, 2020, from https://link.springer.com/article/10.1007/s00296-018-4013-5
- 5AR;, L. (2019, February).
Menopause and Dry Eye Syndrome.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/30594503/
- 6SW;, K. S. (2020, January 13).
Effects of radiation therapy on the meibomian glands and dry eye in patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/31931766/
- 7Javadi, M., & Feizi, S. (2011, July).
Dry eye syndrome.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306104/
- 8De Paiva, C. S. (2017).
Effects of Aging in Dry Eye.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5347479/
- 9Peck, T., Olsakovsky, L., & Aggarwal, S. (2017).
Dry Eye Syndrome in Menopause and Perimenopausal Age Group.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496280/
- 10I;, J. (2013, December).
Diet, nutraceuticals and the tear film.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/24012987/
- 11T;, K. (2018, November).
Contact Lens-Associated Dry Eye Disease: Recent Advances Worldwide and in Japan.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/30481813/
- 12Alanazi, S. A., Alomran, A. A., Abusharha, A., Fagehi, R., Al-Johani, N. J., El-Hiti, G. A., & Masmali, A. M. (2019, June 28).
An assessment of the ocular tear film in patients with thyroid disorders.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6607206/
- 13Ma, W., Wang, G., Li, X., Wu, H., Liu, Z., Dong, N., & Li, C. (2020, August 08).
Study of Factors Influencing Dry Eye in Rheumatoid Arthritis.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429800
- 14Messmer, E. M. (2015, January 30).
The pathophysiology, diagnosis, and treatment of dry eye disease.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4335585/
- 15SC;, S. C. (2017, January).
Effectiveness of an Eyelid Thermal Pulsation Procedure to Treat Recalcitrant Dry Eye Symptoms After Laser Vision Correction.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/28068444/
- 16Emii O, Murat D, Eri H, Asako Y, Rie A,Yukako T, Yoko O, Kazuo T, Eiki G. (2011, January)
Surgical punctal occlusion with a high heat-energy releasing cautery device for severe dry eye with recurrent punctal plug extrusion.
Retrieved October 17, 2020, from https://europepmc.org/article/med/21232733
- 17Shafer, B. (2019, June).
The use of self-retained, cryopreserved amniotic membrane for the treatment of Sjögren syndrome: a case series.
Retrieved October 17, 2020, from http://www.djo.harvard.edu/site.php?url=/physicians/oa/3720
- 18Wakamatsu TH;SantʼAnna AEBPP;Cristovam PC;Alves VAF;Wakamatsu A;Gomes JAP;. (2017, November).
Minor Salivary Gland Transplantation for Severe Dry Eyes.
Retrieved October 17, 2020, from https://pubmed.ncbi.nlm.nih.gov/28922328/
- 19Xu, L., Zhang, W., Zhu, X., Suo, T., Fan, X., & Fu, Y. (2016, October 18).
Smoking and the risk of dry eye: A Meta-analysis.
Retrieved October 17, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5075666/
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