Dry eye disease occurs when the amount and quality of tears produced in the eye is not adequate to keep the surface of the eye lubricated and healthy. The tears produced might be unstable, leading to inflammation and even damage to the eye’s surface. Dry eye conditions cause discomfort that can manifest itself in several ways. There may be stinging or burning, a foreign body sensation, redness, disturbances in vision, sensitivity to light, watery eyes, difficulty with night-time driving, and soreness of the eye.
Some people experience dry eyes in certain conditions – for example, when they are in airconditioned rooms, on airplanes, when they are in windy or sunny conditions, and when looking at screens (e.g., mobile phones, laptops, TV) for long hours at a time. Others suffer from dry eyes under all conditions.
There are a few causes of dry eyes. Your tears are composed of 3 ingredients: fatty oils, aqueous fluid, and mucus. The mixture typically keeps the surface of the eye lubricated, clear, and smooth and this keeps the eye feeling comfortable. Problems with any of the 3 layers disrupts this condition and can cause dry eyes. Dysfunction in tears may be caused by several factors: hormonal changes, inflamed eyelid glands, allergies, and also autoimmune disease. There may also be decreased tear production or increased tear evaporation that lead to the same condition.
Aside from decreasing quality of life and disrupting everyday activities, dry eye conditions can lead to complications such as eye infections and permanent damage to the eyes’ surface.
Decreased tear production
When the eye does not produce enough aqueous fluid (water) this can lead to dry eyes. This occurs:
- With aging
- With certain medical conditions such as lupus, thyroid disorders or Vitamin A deficiency
- When taking certain medications such as antihistamines, HRT, antidepressants, drugs for acne, birth control and
- Through corneal nerve desensitivity such as with contact lens use, or temporary nerve damage following laser eye surgery
Increased tear evaporation
The oily part of tears is produced by tiny glands (meibomian glands) on the edge of the eyelids, which can become clogged. This condition is more common in those with rosacea or other skin disorders. The most common cause of increased tear evaporation are:
- Blepharitis: when the meibomian glands become clogged
- Decreased or incomplete blinking caused by long periods of focusing on an activity such as driving, reading, or working in front of a screen. This can also occur in Parkinson’s disease.
- When the eyelids develop problems that make them turn outwards or inwards
- Eye allergies
- Wind, smoke, or dry air
- Using topical drops with preservatives
- Vitamin A deficiency
Dry eyes often occur following a cataract removal operation for a few reasons. Often these patients are older and may suffer from a concurrent disease such as diabetes, making them more prone to dry eyes. The operation may include tiny cuts (to allow surgeons access to the eye) that compromise the cornea’s surface. Following the procedure, patients are given treatment (antibiotics and steroids) as eye drops which may contain preservatives, which may lead to dry eyes. It is essential to report dry eyes before such an operation as this may affect the procedure and outcome. Vision tests may also be affected by dry eyes.
Digital eye strain
Caused by prolonged use of screens, digital eye strain may also lead to dry eyes. During time spent on laptops, tablets, mobiles, and watching TV, blinking decreases in frequency. This is sometimes accompanied by incomplete blinking. Thus the surface of the eye is not adequately lubricated. It also leads to a decreased production of the oily part of tears, making tears evaporate too quickly from the eye. Screens also emit blue light that inflames the eyes. These can be counteracted by taking frequent breaks from the screen, using blue light filters, applying preservative-free lubricant eye drops, and using a hot compress to encourage healthy tear production.
Contact lens use
Those who use contact lenses are 3 times more likely to develop dry eye disease. Contact lenses should be changed as often as directed by the individual’s specialist. Prolonged use can lead to an intolerance to the lens component contributing to inflammation, redness, irritation, watery eyes, or blurred vision. In addition, the presence of the lens divides the tear film into two layers, which makes already unstable tears more weak. This can be exacerbated by dry eye disease. In this case, a solution might be to wear the lenses for fewer hours at a time, change the lenses more often, and apply preservative-free lubricant eye drops that are suitable for contact lens wearers.
The use of eye drops
Lubricating eye formulas in artificial tears (drops), gels, or ointments are suitable for replacing the lack of production of natural tears. These should be used often in those suffering from dry eye disease, even before symptoms are felt. Preservative-free formulas are best as preservatives themselves can sometimes lead to dry eyes and irritation.
When to see your doctor
If your eye condition is stopping you from doing daily activities because of the significant discomfort you feel, you should seek medical attention so that a specialist can determine the cause of this condition. Also seek help if you are using lubricating eye drops but the symptoms are not helped and do not go away.
Dry eyes—Symptoms and causes. (n.d.). Mayo Clinic. Retrieved June 24, 2021, from https://www.mayoclinic.org/diseases-conditions/dry-eyes/symptoms-causes/syc-20371863
Dry Eye Syndrome: When to See a Doctor. (n.d.). WebMD. Retrieved June 24, 2021, from https://www.webmd.com/eye-health/dry-eye-syndrome-doctor