Pupil Dilation. Tetracaine does not dilate the pupil. This medication is an ester local anesthetic used to anesthetize the eye. Cycloplegic drugs such as atropine, cyclopentolate, homatropine, scopolamine and tropicamide are used as mydriatic (pupil dilating) agents. The duration of action of these medications can range from 4-24 hours or so depending on the concentration of the drug and the individual patient.