If you go to a certain contact lens retailer with deep pockets to pay off Utah legislators, you will find the following quote,
The One Year Myth
Some eye care providers tell you that they cannot issue an expiration date of more than one year. This is not true. One year is a minimum, not a maximum. You should discuss your wearing habits and eye health with your eye care provider to determine if you can have a longer prescription length.
Their whole website is information on how to boss an eye doctor around. If they really want to alter standard clinical practice then they should utilize peer reviewed studies instead of trying to turn consumers into ignorant bullies.