Whether or not a dilated pupil can be recovered depends mainly on what the cause of the dilated pupil is, some can be recovered and some cannot. If the dilated pupil is caused by a medication, such as a point-of-use dilator, like tropicamide used in medical optometry, the dilated pupil will recover in 3-4 hours. If a medium-acting dilator is used, such as postmastopin, it may take 1-2 days to recover. If a strong dilator, atropine, is ordered, it may take 2-3 weeks for the pupil to recover. If the dilated pupil is caused by inflammation or trauma, it is less likely to return. Traumatic pupillary paralysis is likely to remain dilated because the pupillary sphincter is damaged or the nerve that governs the pupillary sphincter is damaged. The damage to the muscle and nerve can only be repaired by your own repair ability, but it is unlikely that you will recover to the same level as before.