For many people, putting contact lenses in is part of their everyday routine.
But some might not be aware that wearing lenses in the shower or when swimming could be putting them at risk of losing their sight altogether, reports the Mirror.
Doing so could result in vision loss caused by an infection known as Acanthamoeba Keratitis - basically, a microscopic organism invading the cornea in your eye.
As explained on the Moorfield Eye Hospital NHS website , this infection affects the clear 'window' at the front of the eye and can be incredibly painful.
It's caused by a microscopic organism, called Acanthamoeba, which is common in nature and is usually found in bodies of water (lakes, oceans and rivers) as well as domestic tap water, swimming pools, hot tubs, soil and air.
Around 85 per cent of cases of the infection have been caused by contact lens wear.
Taking a five-minute shower after your gym class or jumping in the pool on holiday without taking out your lenses could mean that this organism finds its way into your eye.
Failure to disinfect your lenses properly can increase your risk of contracting the disease, which is still very rare.
And if you think UK water is clean enough that you won't get infected by it, think again.
Moorfields' leaflet on the infection states: "Due to the way that UK domestic water is stored and supplied, incidence of the disease is generally higher in the UK than in other parts of the world."
If you do start to experience blurred vision or are worried about your contact lenses, do consult an eye doctor immediately.
Treatment is usually with anti-septic drops administered every few hours (including through the night) as well as anti-inflammatories and painkillers in particularly bad cases.
"In later stages of the disease, scarring on the front of the cornea, resulting from long-term inflammation, is usually the reason for vision loss," the NHS explains.
"In some patients, scarring can be quite extensive and may need further therapy (e.g. a cornea transplant) to rehabilitate vision once the infection is over.
"A degree of permanent vision loss occurs in around a quarter of cases.
"Around 25% of cases of AK seen at Moorfields result in a corneal transplant."
So don't wear contact lenses in the shower, or the bath,or while at a swimming pool and definitely don't wear them swimming in lakes or natural water sources.