Dry eye

Dry eye is a disease involving a scarcity of tears and/or deterioration of the quality thereof, causing inflammation of the eye's surface. It usually affects both eyes and is more common in women than men, particularly during menopause and post menopause. 

The symptoms of patients with dry eye include irritation, itching, burning, stinging, a feeling of dryness and grit in the eye, and even blurred vision and fluctuating visual acuity. 

These symptoms are usually aggravated in dry environments with little humidity and in environments where there is a lot of wind. They are also aggravated when the patient is staring at something and does not blink much. 

Dry eye is a multifactorial disease, i.e a variety of factors cause it. The most common cause is hormonal changes which lead to poor functioning of the tear glands and reduced secreation of tears. Dry eye may be a side effect of systemic diseases, especially autoimmune diseases such as rhematoid arthritis and systemic lupus erythematosus. 

The risk factors are: 

• Age and sex. The older you are, the higher the chance of getting dry eye. And if you're a woman, the risk is greater. 
• Use of contact lenses, chronic use of eyedrops and a history of eye surgery. 
• Failure to close the eyelids properly and infrequent blinking. 
• Chronic inflammatory diseases of the eye's surface like chronic allergic conjunctivitis and eye burns.
• A patient with an autoimmune disease. 
• The use of some chronic systemic drugs like antidepressants and antihistamines.  
• Abusive use of the computer or other electronic reading devices that the patient has to stare at, causing them to blink less often and thus increasing the evaporation of the tears on the eye's surface. 
• A dry environment, with little humidity or a lot of wind. 

The tear film has 3 layers: the lipid layer produced by the Meibomian glands located in eyelids; the aqueous layer produced by the main tear glands; and the mucin layer produced by the cells in the eye's surface. There are 3 main types of dry eye: 

• One with a lack of aqueous layer. There is a scarcity of the amount of tears. 
• One with a lack of lipid layer. The amount of tears is normal but the external layer consisting of lipids that prevent the excessive evaopration of the tear film is missing. The tears of these patients evaporate immediately causing evaporative dry eye.
• Mixed where there is a lack of aqueous layer and the lipid layer. This is the most common type. 

Some risk factors of dry eye are preventible such as overuse of the computer and electronic reading devices as well as overuse of contact lenses. 

In the former case, if using the computer for hours on end cannot be avoided, you should blink frequently when using it and you should rest your eyes for 5 minutes every hour to prevent dry eye also known as computer vision syndrome. 

Dry eye is a chronic disease that does not have a permanent cure. However, treatment has 2 objectives: prevent and cure possible lesions on the eye's surface caused by dryness and alleviate the symptoms of a patient with dry eye. 

Treatment involves:

• Replacing the tears and increasing the lubrication on the eye's surface. Artificial tears are used, preferably preservative-free ones, in the form of eyedrops, gel or an ointment. In severe cases, the use of blood derivatives from the patient themselves in the form of eyedrops is an option. 
• Prevent evaporation of the existing tears on the surface of the eye's surface by using glasses that fully cover the eyes, including the sides. 
• Reduce inflammation of the eye's surface caused by the dryness by using anti-inflammatory eyedrops. The use of this type of drug should be strictly monitored by an ophthalmologist as it has side effects like increased intraocular pressure.
• Improving and stimulating the function of the Meibomian tear glands in the eyelids, thereby increasing the lipid layer to reduce evaporation of the tear film. To reach this objective, a local warm compress on the eyelids, eyelid massage and cleaning of the edge of the eyelid can be used. At the same time, increasing Omega 3 in the diet also helps to improve the composition of tears. 
• Improving the environmental conditions by using an air humidifer or glasses of water with large surfaces like a washbowl. 
• Making the patient aware that blinking is very important for the lubrication of the eye's surface and must be done at least 12-15 times per minute.