Treatment of strabismus and blepharospasm with Botox (onabotulinumtoxinA): Development, insights, and impact

Abstract

Strabismus, deviation of the ocular alignment, can adversely affect quality of life and activities of daily living. Surgery was the prior standard of care for strabismus, but up to 40% of patients required additional surgeries. This need for more effective and less invasive treatment, along with the convergence of other events such as the development of electromyography, purification of botulinum toxin A, and the finding that injection of botulinum toxin type A could paralyze the hind limbs of chicks, led Dr. Alan Scott to investigate injection of his formulation for strabismus. The positive results of initial trials in monkeys segued to human trials with observations of alignment improvements and few adverse events. The success of botulinum toxin type A in the treatment of strabismus led to interest in its use to treat other skeletal muscles, particularly in blepharospasm, a type of focal dystonia involving eyelid spasms and involuntary eye closure that lacked an effective pharmacological treatment. Patient groups helped to increase awareness of this novel treatment, and results from clinical trials confirmed its effectiveness. Dr. Scott’s formulation, then known as Oculinum, received its first Food and Drug Administration approvals in 1989 for strabismus and blepharospasm. Allergan acquired Oculinum in 1991, renaming it Botox. These initial uses led to its application in a myriad of other indications as outlined in other articles of this supplement.

Prevention, Diagnosis, and Management of Diplopia Secondary to Neurotoxin Injections

“…Aesthetic practitioners must undergo rigorous training in anatomy and injection techniques, be aware of and adhere to best practices, engage in ongoing learning, and develop exceptional communication skills. The importance of ensuring patient safety cannot be overstated (Delle Chiaie, 2024, p. S36; Nestor et al, 2021; Scott et al, 2023; Witmanowski & Błochowiak, 2020).…”

“…When a definitive diagnosis cannot be made, or if there are concerns about other potential causes for the diplopia, the aesthetic practitioner should refer the patient to a neurologist or ophthalmologist/oculoplastic surgeon for a more comprehensive examination. There is some evidence to show that injections in the agonist muscle are beneficial for creating balance and helping to restore vision and pupillary alignment (Delle Chiaie, 2024; Ganesh et al, 2019;Isaac et al, 2012;Kroumpouzos et al, 2021;Najem & Margolin, 2023;Scott et al, 2023). Thoroughly document every step of the evaluation, treatment decisions, and patient communications in the medical record.…”

“…In most cases, the diplopia is caused by a weakened extraocular muscle. When the diplopia is accompanied by a palsy, it is generally caused by a complete paralysis of the involved muscle (Delle Chiaie, 2024; Khan et al, 2023; Scott et al, 2023).…”

From Toxin to Treatment: A Narrative Review on the Use of Botulinum Toxin for Autonomic Dysfunction

“…The first classical accounts of BoNT were reported in 1817 when Justinus Kerner discovered sausage-borne BoNT and Emile Pierre van Ermengem described a BoNT outbreak in a Belgian village in 1897 [ 2 , 3 ]. It was not until the 1970s that BoNT was used for clinical use by Dr. Alan Scott for the treatment of strabismus [ 4 ]. In 1989, botulinum-A toxin (BoNT-A) was approved by the United States Food and Drug Administration (FDA) for treating strabismus, blepharospasm, and facial nerve disorders, and in 2000, the FDA-approved botulinum-B toxin (BoNT-B) for cervical dystonia [ 5 ].…”