How widespread infections may soften your eyeball till the jelly leaks out: Top medical doctors inform defend your self – and reveal the the backyard parasite that may make you go blind

I’ve lost my eyesight,’ Sir Elton John revealed at the weekend while attending a performance of new musical The Devil Wears Prada in London‘s West End.

Five months after he developed an infection in his right eye, the legendary singer-songwriter says he’s unable to see out of it.

And as the other eye ‘is not the greatest’, he’s effectively blind.

While it’s hoped that the sight in his ‘good eye’ will return eventually, he’s been unable to work for several months.

Sir Elton, 77, told ABC News Good Morning America recently: ‘I can’t see anything. I can’t read anything. I can’t watch anything… [but] there’s hope and encouragement that it will be OK.’

It’s the kind of story that will have alarmed many.

Every day 250 people start to lose their sight in the UK, the equivalent to one person every six minutes, but only a tiny proportion are due to infections, says Mike Burdon, a consultant ophthalmologist at Bishop Auckland Hospital, County Durham.

‘It sounds like he [Sir Elton] has been very unlucky, because most eye infections are temporary and don’t cause long-term vision problems,’ says Mr Burdon. ‘In fact, it is very rare for an infection to lead to blindness.

‘One possibility is that he could have been affected by a severe case of keratitis, an infection affecting the cornea, the clear dome in front of the eye, causing vision to go blurry.

‘This is extremely painful, like a toothache of the eye, and potentially sight threatening.’

The condition is caused by bacteria, viruses or, more rarely, fungal infections or those passed on from contaminated water, says Melanie Corbett, a consultant ophthalmologist and eye surgeon at the Western Eye Hospital, which is part of Imperial College Healthcare NHS Trust.

Keratitis is also more likely if you have blepharitis – inflammation of the eyelid margin caused by bacteria, making it crusty and sore.

‘Blepharitis may affect more than half the adult population, although many people don’t know they have it,’ says Ms Corbett. She warns that the treatments recommended by some opticians – swabbing the affected area with wipes and solutions containing chemicals such as alcohol – can actually make things worse by damaging the corneal surface.

‘Remove debris with a clean flannel and hot water only,’ she says.

The usual route for any infection-causing bug is rubbing your eyes and the most common type of eye infection is conjunctivitis.

Caused by bacteria, viruses or allergies, it’s characterised by inflammation in the tissue in the front of the eye and inner eyelid – you will have red gritty eyes which are inflamed and sticky.

Keratitis, which affects the cornea specifically, is much more serious. In England alone, more than 2,700 people are admitted to hospital every year with a suspected corneal infection caused by keratitis. Ms Corbett says that most people are put on an intense treatment plan to try to reduce the infection as soon as possible.

This is because the surface of the cornea ‘has usually been damaged in some way [for example as a result of wearing contact lenses], so it is more porous to infection. Healthy people with healthy eyes do not get keratitis.’

It is more common in people who wear contact lenses and also those with reduced immunity because of disease or medications.

Treatment depends on what caused the infection. If bacteria have invaded the cornea, they can start to destroy the cells of the surface layer (the epithelium), and ‘melt through’ the deeper level perforating the eyeball.

‘The hole causes the aqueous humor [the jelly that gives the eyeball its shape] to leak out of the hole and needs to be repaired surgically. I currently perform around one of these critical operations a month at the Western Eye Hospital.’

First-line treatment is antibiotic eyedrops which need to be applied hourly day and night for at least 48 hours and the whole treatment plan lasts several weeks, says Ms Corbett.

Severe scarring of the cornea can cause life-long vision loss. But in most cases, over time, it can be treated successfully and the cornea heals, so sight returns.

Viral keratitis, which can be caused by the cold or flu virus or the herpes simplex virus (which causes cold sores), can also affect vision but in a different way as white spots form on the surface of the cornea.

‘It is much less likely that viral keratitis will cause long-term vision loss, and although anti-viral tablets or ointments can help, many people get better without treatment,’ says Ms Corbett.

Even simple infections can cause sight loss depending on which part of the eye is affected.

Some people are more likely to develop eye infections of all types.

Contact lens wearers are more at risk because they are putting foreign objects in their eyes on a regular basis. According to Moorfields Eye Hospital in London: ‘Approximately one in 3,000 people develop a serious corneal infection every year from wearing contact lenses and some of these patients will require a corneal transplant.’

A specific risk is acanthamoeba keratitis, a condition that can cause severe pain, extreme sensitivity to light and, in at least a quarter of cases, blindness.

Acanthamoeba is a microscopic parasite found in soil and water – including tap water.

It can get into the eye through gardening, but the main cause is if any water containing the parasite gets trapped between the cornea and the contact lens. The parasite can then eat into the cornea.

This is why contact lens wearers are warned to remove their lenses before swimming and showering, and not to wash lenses in water.

Injury to the eyes can also increase the risk of infection, so you should put on protective eyewear when playing sports, suggests Mr Burdon.

‘Participating in sports or recreational activities without appropriate eye gear increases the risk of eye injuries from debris, projectiles, or accidental impacts,’ he says. ‘Wearing protective eyewear, such as goggles or safety glasses, is essential to prevent potential harm.’