: Eyes vary in curvature and diameter; a "one-size-fits-all" lens can cause scratches, ulcers, or infections.
: Stores like Walmart Contacts can verify your prescription directly with your doctor. where can i buy over the counter contact lenses
: Contacts are Class II or III medical devices because they sit directly on the cornea. : Eyes vary in curvature and diameter; a
Once you have a valid prescription from an eye doctor, you are free to shop at various licensed retailers: a "one-size-fits-all" lens can cause scratches