As with all types of surgery, there are several risks and possible complications involved with having a cornea transplant.

Some problems are obvious soon after surgery and need emergency treatment. Others may be spotted during follow-up appointments.

Rejection happens when your immune system recognises the donated cornea as not belonging to you and attacks it.

It's quite a common problem, with symptoms of rejection occurring in about 1 in 5 full-thickness corneal transplants, although only about 5% of low-risk grafts actually fail because of this.

Serious rejection is rare after deep anterior lamellar keratoplasty (DALK).

Rejection can occur a few weeks after a cornea transplant, but it's more common after several months.

The problem can often be treated effectively with steroid eyedrops if treatment begins as soon as you notice symptoms.

You should seek emergency specialist advice if you notice these symptoms after having a cornea transplant:

• red eye
• sensitivity to light (photophobia)
• vision problems – particularly foggy or clouded vision
• eye pain

As well as rejection, there's a risk of further problems after cornea transplant surgery.

These can include:

• astigmatism – where the cornea is not a perfectly curved shape
• glaucoma – where pressure builds up in the eye as a result of trapped fluid
• uveitis – inflammation of the middle layer of the eye
• retinal detachment – where the thin lining at the back of your eye called the retina begins to pull away from the blood vessels that supply it with oxygen and nutrients
• the original eye disease (such as keratoconus) returning
• wounds from surgery reopening
• internal infection as a result of surgery wounds