Usually it is under the local laws which in general
While using contact lenses you should rinse them every time you wear and remove them to prevent yourself eye infections. It should be remembered that lenses stored more than 12 hours should be rinsed properly before using them. It is better to remember that the solution is when one is used, to store them in proper condition; it shall neither be dried nor expired. Precautions mentioned on their label should be followed accurately. Lubricants (solutions) other than prescribed or recommended like saliva; tap water, etc., should not be used for lubricating or wetting those lenses.
Care needs to be taken against any fume, dust or any other irritating or harmful particle while wearing them. And also avoid creams, lotions, deodorant and other cosmetics from getting into your eye while wearing lenses. While removing your lenses care must be taken too, you should keep on rinsing and washing your hands, also do not use tweezers, fingernails and other non-prescribed tools. Do not forget to remove your lenses before going to sleep until and unless it is advised by your eye specialist because it might harm your precious eye. It is also generally recommended that while wearing your contact lenses do not use any eye drop and any other eye medication other than the case where it is advised by your eye specialist.
In some instances there are symptoms of adverse reaction like feeling discomfort, constantly excessive tears, changes in your vision, your eyes become red and you also felt to be more sensitive for light, than immediately remove your lenses and consult your doctor so as to minimize the risk associated with that reaction. It may be caused due to any reason but it can further result in severe sight effects. Many medical professionals do not advise to wear contact lenses for many hours as with a long period of time chances of adverse reaction goes beyond acceptable and manageable levels.
In a nut shell, contact lens bears significant risk and reward for its user. To extract maximum benefits with minimum risk proper knowledge and understanding must be there to make life easier otherwise problems can occur like adverse reaction and reducing more eyesight and other related issues. Cure can only be guaranteed after proper precautions have been undertaken.
It is right said that 'prevention is better than cure.'