How close can he see things in focus without any corrective lenses?
29. It is now possible to purchase bifocal contact lenses (these are contact lenses with twodifferent refractive powers, one to help with distance vision and the other to help with near—vision.) When wearing his contact lenses, John can see objects in focus as close as 25 cm fromhis eyes. If his prescription for these contact lenses reads “+3.00 D", how close can he see things in focus without any corrective lenses?