Usually 6-8 hours. It depends on what type of drops are used. Phenylephrine and tropicamide are probably the most commonly used at the optometrist or ophthalmologist's office and they last about 6-8 hours in the average person, although they can last a bit longer. Other drops like cyclopentolate last up to 24 hours and Atropine can last for 14 days.
Depends. Depends on the type of medication that was used. Most drops used in the office should wear off in a few hours however there are drops that can keep the eye dilated for up to a week.