Dry Eye Disease (DED)
Through the course of our lives most of us will experience the symptoms of Dry Eye Disease. Gritty, sore, red eyes, blurred vision and light sensitivity – Dry Eye Disease can cause them all. It may sound simple but Dry Eye Disease is a complex and difficult condition to pin down and the TFOS DEWSII report from 2017 gives us the most up to date definition:
“Dry eye is a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.” (TFOS DEWSII Report 2017)
OK….
The tear film plays a vitally important role in protecting the delicate surface of the eye and providing a clear, smooth surface that allows us to see clearly. There are three layers to our tear film:
- A base layer of mucin (mucous) that allows the tear film to spread over and attach to the surface of the eye.
- A middle layer of liquid called the aqueous layer that also contains electrolytes, proteins and antibodies.
- A top layer of oil (lipid) that reduces evaporation of the tear film
Disturbing any one of the three layers will cause the delicate balance of the tear film to fail and cause Dry Eye Disease. Once the tear film loses it’s stability it becomes more concentrated (hyperosmolarity) leading to inflammation of the surface of the eye and the eyelids.
There are two main types of Dry Eye Disease.
- Aqueous Deficient Dry Eye – the eyes are no longer producing enough liquid (aqueous)
- Evaporative Dry Eye – the tear film is being allowed to evaporate from the surface of the eye to quickly
In most cases both of these can be present to a greater or lesser extent making Dry Eye Disease even more difficult to combat.
Who is at risk of Dry Eye Disease?
Dry Eye Disease is more common in women, people from an Asian ethnic background and in people aged over 50. It is often just a symptom of getting older.
As you get older, you produce less tears and your eyelids are not as effective at spreading them when you blink. The meibomian glands (oil glands) also become less effective as you get older and can become blocked.
In women, changes in hormone levels can increase the risk of dry eye. This means symptoms may be worse during menopause or pregnancy or while using a contraceptive pill. Your doctor or optometrist will be able to give you advice on this.
Other things that might increase your risk are wearing contact lenses, a low blink rate, having an abnormal eyelid position or laser eye surgery.
What can I do about Dry Eye Disease?
As Dry Eye Disease is a chronic condition you may need ongoing treatment to manage your symptoms. Your optometrist can then give you advice on how to manage it.
There are four main ways to help reduce the symptoms of dry eye:
1. Keep your eyelids clean and avoid makeup. Clean the edges of your eyelids with a lid care product or wipe. Clean close to your eyelashes and wipe from the inside (near your nose) to the outside corner of your eye. Repeat this twice a day at first and reduce this to once a day as the condition improves.
2. Be aware that some environments that may make your eyes feel more dry. High temperatures and central heating, draughts and air conditioning may make your tears evaporate more quickly.
If you are out on a windy day you may find it useful to wear glasses or sunglasses (ideally the wraparound type) to protect your eyes from the wind.
Try to avoid smoky atmospheres as these may irritate your eyes.
3. Use eye drops to ease your symptoms. These work by giving your eyes the extra moisture and lubrication they need. There are lots of different drops available and they contain different ingredients that work better for some types of dry eyes than others. Your optometrist will be able to recommend an eye drop that is most likely to help you.
If you find the relief from drops is not effective you may find a gel works better, this is because they are thicker and stay on your eye for longer.
If you have dry eyes at night because your eyelids do not close well enough you can use an ointment.
Some drops contain preservatives which may make your eyes sore and if you are using a lubricant more than six times a day you should use one that is preservative-free.
4. Have treatment to reduce the amount of tears draining away. Your tears drain away into your nose through four small drainage channels in your eyelids (one in each of the upper and lower lids). Small plugs, called punctum plugs, can be placed in the holes in your lower eyelids to help the tears to stay in your eye for longer.
Using a computer
You may find that your eyes feel dry while they are looking at a computer screen (or afterwards) because you blink less often staring at a screen. Try to blink often and look away from the screen regularly for a few seconds. This will help replenish the tear film and give your eyes a rest.
This information is a guide and should not replace advice that your optometrist or other relevant health professional gives you.
For more information visit RNIB and Glaucoma UK
