Question

why do spectacles get cloudy deposit on them on moving out from an air-conditioned place (car,room) etc.

Answer 1

Because fog comes on it by the ac

Answer 2

probably due to the water vapor presence in air. In air conditioned rooms the air is too cold where the water vapor present in the air slowly condenses to water in liquid form.thus, your spectacles or any other soft and shiny obkect may collect water vapor on it.