Pterygium is a growth of fibrous tissue and blood vessels, which can affect the conjunctiva, the outer lining of the eyeball. Pterygia grow in the corner of the eye, where the upper and lower eyelids meet, and 9 out of 10 pterygia develop in the corner of the eye nearest the nose. They are usually painless but as they increase in size they can interfere with vision.

Pterygia are benign, non-cancerous growths. But although they are not cancers they often come back after surgery. Somewhere between 1 in 3 to 2 out of 3 people who have one of these growths removed will find that it comes back after the operation. About half of these recurrences appear within a year of the surgery and most will have appeared within two years.

One way of reducing the chance of a recurrence is to give some radiotherapy treatment to the eye after the operation has removed the growth.

This is a special type of radiotherapy treatment that uses a metal applicator which is coated with the radio-active isotope strontium-90. This gives off a type of radiation (beta-rays) that only affect tissue very close to the applicator and do not reach any other part of the body. Local anaesthetic drops are put in the eye, so there is no discomfort, and the applicator is then very gently rested against eyeball for a few minutes. The treatment is painless, simple and can be done as an out-patient.

The radiotherapy may leave the eye rather sensitive for a week or two (the eye may be a bit bloodshot, itchy and sensitive to bright light), and some soothing eye drops may be needed to ease these symptoms. This temporary sensitivity settles within a week or two. Long-term side-effects, which can include watering of the eye, dryness of the eye or a bloodshot eye, are uncommon, affecting less than 1 in 20 people.

Giving radiotherapy after surgery to remove pterygium reduces the chance of a recurrence of the growth to about 1 in 20. It is usually most effective if it is given the first time a growth is removed, rather than waiting for recurrences to develop and then giving it.

So, although the doctors may be talking about radiotherapy for your mother’s condition you can be reassured that she did not have a cancer of her eye.