More than three million people in the UK wear contact lenses - which shows how popular they are.
However, the NHS is concerned that around 70 per cent of these people are not following manufacturer instructions on how to look after their lenses or their eyes.
It highlights the fact that wearing contact lenses heightens the risk of eye infection - but this risk is minimal if good hygiene is used at all times.
The NHS eye health pages quotes a list of potential risks from the College of Optometrists, which backs up the manufacturer leaflet included in all online sales of contact lenses.
Issues listed include using dirty contact lens cases, not paying attention to the specific treatment of the prescribed brand of contact lenses and failing to disinfect lenses after use (if they are not daily disposable lenses).
The right prescription is important and before buying contact lenses on the internet, people should ensure they have had an eye examination within the last two years.
Prescriptions can be used to bulk order contact lenses - which can work out cheaper over the long-term than ordering on a monthly basis.
by Alexa Kaczka