Method: This randomized clinical trial study with control group included 66 eyes of 66 peristent corneal defects persistent corneal defects patients with over 12 years old. Subconjunctival injection chemodenervation of levator palpebrae superioris was performed using Botulinum Toxin type A (Dyport) in to the levator palpebrae superioris muscle without guiding of electromyography.