What is this condition known as dry eyes?
Dry eye is a common and chronic condition in which a person lacks a normal tear film to lubricate the surface of the eye and allow for clear vision. It is particularly common in older adults over the age of 50 years, especially amongst women. Over time, tear deficiency also leads to inflammation of the eye surface and causes chronic eye discomfort and redness.
People with dry eyes usually do not have enough tears or have a poor quality tear film:
Inadequate tear volume
Tears are produced by several glands in and around the eyelids. Tear production tends to diminish with:
- Age – tear production decreases with age
- Gender – women are more likely to develop dry eyes due to hormonal changes seen in pregnancy, use of oral contraceptives or with menopause
- Certain medications – antihistamines, antidepressant, blood pressure medications
- Certain medical conditions – particularly with automimmune conditions such as rheumatoid arthritis, Sjogren’s syndrome and diabetes
Although external environment and excess screen time are not direct factors in tear production, dry and windy climates and decreased blinking with screen time can also lead to greater evaporation of eyes and tear deficiency.
Poor quality of tear film
Normally, tears are made up of three crucial components: oil, water and mucus:
- The oily component (produced by the meibomian glands in the eyelids) is the outermost layer and slows down the evaporation of tears from the eye surface
- The middle aqueous layer (produced by the lacrimal or tear glands)
- The innermost mucus layer (produced by the goblet cells on the surface of the conjunctiva) which helps to spread the aqueous layer evenly over the eye surface
Disruption to these three layers cause evaporative dry eye, aqueous dry eye and mucous dry eye conditions respectively.
Meibomian gland disease is the main cause of evaporative dry eye. It is therefore important to identify this in the work-up for dry eyes and address it appropriately.
Aqueous dry eye is caused by the conditions listed in the section earlier.
Mucous dry eye can be due to conditions such as contact lens overwear, previous chemical injury to the eye or Steven-Johnson syndrome which reduce goblet cell population.
What are the symptoms of dry eyes?
Symptoms of dry eye include:
- Eye discomfort or irritation; some describe a foreign body sensation in the eye
- Occasional tearing (due to a reflex action as the eye increases tear production sporadically in response to the sensation of dryness in the eye )
- Eyelids that tend to stick together in the morning due to mucoid discharge that forms as a result of eye surface inflammation
How are dry eyes diagnosed?
In most clinics, your eye doctor will first take time to listen to your complaints and then follow through with a detailed examination of the eye surface and the eyelids. Tell-tale symptoms and signs will raise the clinical suspicion of dry eyes in which case your eye doctor will run a few clinical and investigative tests to confirm the diagnosis.
These tests include the use of certain special stains to assess the status of the ocular surface, the tear film break-up time and Schirmer’s tear test. There are other tests available in the research setting that are usually not available in the clinical setting.
How dangerous is dry eyes?
If left untreated, severe dry eye can cause chronic defects on the surface of the cornea, leading to scarring, thinning or even perforation of the cornea, especially if secondary infections set in. This could potentially lead to permanent vision loss.
Treatments offered by eye clinics
Traditional and newer dry eyes treatment methods focus mainly on replenishing the aqueous portion of the tear film, reducing the amount of tears lost due to evaporation, and controlling the inflammation seen in more severe cases.
More recent research has shown some potential for the use of autologous serum, platelet-rich plasma products, umbilical cord blood serum and mesenchymal stem cells (to regenerating the meibomian or lacrimal glands) in the treatment of dry eyes. But, these are not readily available and in the case of mesenchymal stem cells, still in the experimental stage of research.
Replenishing the aqueous layer
Tear substitutes or lubricants are helpful in restoring the aqueous layer of the tear film. There are many available in both liquid and gel or ointment form. Some are more suitable for aqueous dry eye and others for evaporative dry eye. Your eye doctor will be able to advise on which are most suitable. Generally speaking, preservative-free tear lubricants are preferred for those with chronic dry eye to avoid further irritation by additives.
Omega-3 fatty acid supplements may also be helpful in increasing tear production.
Reducing evaporative loss of tears
Treating the underlying problem of meibomian gland disease is important in reducing tear loss by evaporation. This usually involves the use of warm compresses, eyelid massage and lid hygiene measures, often accompanied by the use of topical antibiotics. Oral antibiotics are occasionally required in more severe or recalcitrant cases of Meibomian gland disease.
Cyclosporin eyedrops have been used effectively to treat the inflammation seen in those with more severe dry eyes. This medication has also been shown to increase the number of mucus producing globlet cells in the conjunctiva. Many eye doctors now recommend this if a patient does not improve on the above measures alone and cannot get by without daily tear substitutes.
In some cases of severe dry eye, very careful and supervised short-term use of steroid eye drops may also be appropriate in managing the symptoms and complications associated with dry eyes.
Simple self-care measures such as blinking more frequently during screen time and wearing sunglasses when out in windy conditions are helpful in alleviating dry eye symptoms.
Some common queries about dry eyes
Why are my dry eyes getting worse?
If dry eyes are neglected, an inflammatory component comes into the picture and makes the person with dry eyes more symptomatic. So from the occasional dry sensation, the person with dry eyes starts to feel more discomfort and redness.
To prevent this, early identification and institution of appropriate measures is important. Once the inflammatory component comes in, treatment tends to be more complex with more frequent visits to the eye clinic.
Why do my eyes get dry when I wear contact lenses?
In the early stages of dry eye, wearing contact lenses may help alleviate the symptoms as the contact lens acts as a bandage and covers up the surface defects on the cornea.
However, this is not a solution to dry eyes as continued and prolonged contact lens wear can contribute further to the dry eye condition and exacerbate the problem. Of greatest concern is the risk of infective corneal ulcer when contact lenses are worn in dry eye conditions.
Can eye drops make dry eyes worse?
Certain eye drops contain active ingredients or preservatives that may further irritate the eye that is already dry. Some common culprits are glaucoma eye drops and other medications that contain preservatives such as benzalkonium chloride.
Does a lack of sleep worsen dry eyes?
This is not known to be a risk factor for dry eyes.