This is a prospective, randomized, double-masked, comparative study in patients who present at the Robert Cizik Eye Clinic with horizontal forehead rhytides requiring treatment with botulinum toxin Type A (Botox ®; Allergan, Irvine, CA, USA).
The objective of this study is to determine whether there is a difference in clinical effect (weakness/paralysis of the frontalis muscle), duration of effect, level of discomfort and patient satisfaction in patients receiving topical anesthesia (2.5% lidocaine/2.5 % prilocaine cream, Impax Laboratories, LLC) on one side of the forehead and petrolatum ointment on the other prior to BTX-A administration for the treatment of forehead rhytides.
* Primary outcome variable is change of eyebrow excursion on each side of the forehead from baseline to each follow-up visit.
* Secondary outcome variables
* Duration of effect, defined as the elapsed time from injection to the end of botulinum, such that return of baseline frontalis function, i.e. within 2 mm of baseline value
* Perception of pain immediately after injection at each side
* Patient satisfaction for each side
* Patient's perception of difference in efficacy
