About dry eyes
Tears lubricate the eyes and stop the surface from dying. A thin film of tears is swept over the eye surface every time you blink.
A watery layer of tears is topped with an even thinner coat of oil (lipids and fatty compounds) that help to preserve and stabilise the tear film. To maintain eye comfort and health, the tear film needs to remain intact between blinks.
A person suffering from dry eye syndrome does not have enough of the right kind of tears to keep the eye comfortable. This can happen if they do not produce enough tears to keep the eye surface moist, or if there are not enough oils in the tears to stay on the eyes long enough.
Over time, the resulting dryness can damage the surface of the eyeball.
Like Blepharitis, typical symptoms can include:
- Blurred vision
- Burning sensation
- Watery eyes
- Scratchy/gritty/sandy sensation
- Sensitivity to light
- Feeling of “something in my eye”
Anatomy of the tear film
- Lipid (oil) layer: lubricates and prevents evaporation.
- Aqueous (water) layer: nourishes and protects the cornea.
- Mucin layer: adheres tears to the eye.
Causes of dry eyes
Also like blepharitis, the common reason for dry eye is ageing, because both eyes tear flow rate and effectiveness of your tear film decrease with age.
Many factors in your surroundings can also contribute or lead to dry eyes problems including: air conditioning, fan and heating in some homes, offices or shopping centres, extremes in humidity, air pollution, cigarette smoke and dust. Staring at computer screens or television causes a decrease in the rate of blinking which can exacerbate dry eye symptoms.
Certain medications (taken for other conditions) can also cause dry eye if they affect the glands around the eye. Also, some diseases such as Sjogren’s Syndrome which is experienced by suffers of rheumatoid arthritis can cause dry eyes.