It depends on various factors, some of which are the following: The place where we live. Latitude of the country. Level of exposure to the sun ( higher in tropical and equatorial regions.) Race. Other less important factors would be environmental irritants, genetic predisposition, previous eye trauma. Deficiency of eye lubrification.All these conditions have been noted as a cause of the appearance of pterygium. Different studies about the frequency of it in the general population vary widely from 1-2% up to 43% , the figures being influenced by the above factors.

Symptoms are usually varied so that we can find a totally asymptomatic patient with only a little unaesthetic redness of the eye to other more serious ones. These could be permanent irritation, the feeling of a foreign body in the eye or like grit, itching, stinging, or burning. The more worrying ones could seriously compromise your sight in advanced or recurring cases and could even limit eye movement.

Normally the ophthalmologist (Eye doctor), carries out a totally painless examination with a special instrument called a slit lamp. It is a magnifying microscope with certain characteristics which allows us to see the anomalous tissue growing from the internal, or less often, external corner of the eye and which is now overlaying the cornea.

There is no definitive treatment to prevent the Pterygium, if we can take some measures to reduce its incidence in some way, among which we have:

• Wear sun protection goggles
• Protect your eyes from dry and dusty conditions with the use of appropriate glasses.
• Application of artificial tears to avoid eye dryness in adverse conditions.

In the majority of cases if the patient has no symptoms no treatment will be required or at most lubricating drops. In situations where there is either continuous discomfort or difficulty in seeing, it is treated by surgery. There are various techniques, some better than others. Perhaps the most efficient is extraction under a surgical microscope as an outpatient to the operating theatre. Having applied a local anaesthetic in drop form previous to surgery, extirpation of the fleshy part is carried out then, depending on the degree of pterygium, a portion of the conjunctiva will be sutured as a safeguard against regrowth.

In some cases after extraction of the pterygium, substances, such as Mitomicina C, diluted to a very low concentration, are applied to the bed of the wound so as to prevent it from starting again.

In some cases, up to a quarter of them can come back, sometimes more aggresively, it all depends on the skill of the surgeon, how advanced the pterygium is and the environmental conditions which provoked it

Use good quality sunglasses in our area, if they are not, it could be counterproductive. Avoid direct exposure without protection where it is dusty, windy or where there are other environmental contaminants. Avoid dry eyes by using artificial tears including those people who spend hours in front of a screen, staring at data. Blinking is reduced at this time so the eye isn’t lubricated properly. Finally, not everything which appears to be a case of pterygium is so, given that sometimes there are lesions and malign tumours which look like it.