Dry eye is a very common condition. It occurs as a result of a reduction in the quantity or quality of your tear film. This leads to the eyes feeling irritable and sore. In some cases the eyes will also appear red or injected.
The tear film is made of several layers and is a complex structure. We think of the tear film as three layers.
1. A mucus layer which allows the tear to adhere to the surface of the eye. Any condition which disrupts the conjuctival surface of the eye can prevent the tears adhereing to the surface of the eye.
2. A middle watery (aqueous) layer which is formed by the tear (lacrimal) gland which sits beneath the outer aspect of the upper eyelid. In some cases the lacrimal gland may not produce enough aqueous resulting in dry eye.
3. An oily layer which is produced by the oil or ‘meibomian’ glands. There are a large number of these glands found in both the upper and lower eyelid. Conditions such as blepharitis can result in disruption to oil production. This causes the tears produced by the lacrimal gland to evaporate giving rise to dry eye.
There are several things that can be done at home to help manage dry eye. In cases of blepharitis, the eyelashes can be cleaned to remove the debris. This can be achieved by filling a cup with warm water and a couple of drops of baby shampoo. This creates a weak detergent that can be used to clean the eyelid using a cotton-tipped ear bud. You should aim to clean the lashes twice a day.
The meibomian glands can be encouraged to secrete their important oils by applying warm compresses twice daily with simultaneous eyelid massage. You can simply apply a warm face cloth to the closed eyes when in the bath or shower for a period of two minutes. Other options include re-usable packs that can be applied to the eyelids such as those made by the Eyebag Company (www.eyebagcompany.com).
Flaxseed oil can be tried as second-line option. Flaxseed oil is rich in omega-3 oil which is though to improve the quality of the tear film and potentially reduce inflammation of the eyelid.
We usually encourage you to keep well hydrated; this maximises your tear production.
Ocular lubricants can be used to improve the surface of the eye. There are a large number of lubricants available in on the market. Different lubricants will treat different problems. For example a lubricant used for aqueous deficiency (i.e. a reduction in tear production by the tear gland) is different to a lubricant that we might prescribe for oil deficiency (i.e a problem with the oil glands). Mr Norris will discuss with you the best lubricants to use when you are reviewed.
In some cases a steroid or antibiotic may be need to be applied to the eyelid (in the form of either a drop or an ointment) to reduce the inflammation. You shouldn’t use steroid ointments or drops without advice from an Ophthalmologist.
If you think of your eye as a bath, your dry eye occurs when the bath is empty. This can occur because the ‘tap’ or tear gland does not produce enough tears. One method of improving the surface of the eye (akin to filling the bath) is to put a plug in the tear duct. These are known as punctal plugs and can significantly improve dry eye in cases where lubricants alone are ineffective.
Author: Mr Jonathan Norris FRCOphth