Do the contact lenses harmful the eye ?

It can be!: Contact lenses often provide better vision than the glasses but if not used properly, it can be very harmful to the eye. It should be removed every day and never sleep with them. Over use can lead to an infection of the cornea and can lead to blindness. In which case, you will need a corneal transplant surgery.

Can be harmful: Contact lenses are great but they require care and can be harmful if not used appropriately. You should have your eye doctor provide complete education on the safe use of lenses.