A method including transmitting, by a first processor disposed in or on a first ophthalmic device, first data to a second processor disposed in or on a second ophthalmic device； transmitting, by the second processor, second data to the first processor； determining, by the first processor and during a time period, a first characteristic of a user based on at least the second data； and determining, by the second processor and during the time period, a second characteristic of the user based on at least the first data.
