What are “dry eyes”?
To remain healthy the surface of the eye requires a continuous layer of lubrication and moisture. This thin fluid layer is commonly referred to as the “tear film”. It is produced by various glands around the eye and is renewed frequently. It is composed of a mixture of water (aqueous), oil (lipid) and mucus. Blinking helps to distribute the tear film over the eye.
The function of this layer it to protect the surface of the eye by hydration and nourishment, and by providing protection from infection, for example by clearing debris. The cornea has no vascular supply and therefore relies on the tear film to provide oxygen and nutrition.
Dry eyes occur when there is a problem with the production, composition or distribution of the tear film.
Evaporative dry eye, due to meibomian gland dysfunction, is the most common cause of dry eyes. The meibomian glands, which line the edge of the upper and lower eye lids, help produce the oil component of the tear film. This lipid layer helps to reduce evaporation of the aqueous layer. There are multiple factors that may impact upon meibomian gland function, including certain skin conditions such as rosacea, rheumatological diseases such as rheumatoid arthritis, eye injury or surgery, certain medications, allergens, or even contact lenses. You may be familiar with the condition blepharitis, in which the eye lid margins become inflamed. This is both a cause of and a consequence of meibomian gland dysfunction.
Reduced aqueous production by the lacrimal glands, which are located just above the eyeball, is another cause of dry eyes and can occur in conjunction with evaporative dry eye. This is commonly associated with auto immune conditions such as Sjogren’s Syndrome and also has other non-auto immune causes.
How do I know if I have dry eyes?
A person with dry eyes may experience one or more of several symptoms including:
- sore, gritty or watery eyes
- reduced or blurred vision
- sensitivity to light
- pain or red eyes
If you have any of these symptoms it is important to seek advice from an optometrist or GP who can assess your symptoms and offer advice and/or some treatment or refer you to an ophthalmologist if they think you may need additional assessment and intervention.
How are dry eyes treated?
The successful treatment of dry eyes ultimately depends on discovering the cause.
For example, it may simply be due to reduced blinking frequency, and the consequent effect on tear film, due to staring at a computer screen or smartphone for long periods of time. Taking regular breaks could solve the problem. Or it may be that you are sensitive to a particular skin care product or cosmetic and omitting it from your routine could improve your symptoms. Good contact lens hygiene, a healthy diet and adequate hydration are all also important factors in maintaining a healthy ocular surface.
If the cause is due to it meibomian gland dysfunction as described above, then it may be that treating the underlying problem is sufficient or that additional medication is necessary. This could be in the form of topical drops, ointments, gels, artificial tears or oral medication. Hot compresses form a very important part of treatment for patients with evaporative dry eye. There are several available on the market.
What happens if dry eyes are left untreated?
It can be very unpleasant to suffer with dry eyes, impacting on daily activities and enjoyment of life. In some serious cases the ocular surface can become damaged, inflamed or infected, which may lead to visual impairment or even blindness.
Thankfully, most cases of dry eyes can be treated either with short term intervention, or long-term medication.
If you think you have dry eyes, please consider making an appointment with an ophthalmologist to assess your symptoms and discuss your treatment options.