Botulinum toxin is produced by Clostridium botulinum and includes six antigenically distinguishable toxins, labeled A, B, C, D, E, and F. More
work has been done with type A than with any of the other toxins, in part because most strains of this type retain their toxigenicity well, yield highly potent culture fluids (106 mouse LD/ml) in a variety of media, and the toxin can easily be crystallized in a stable form. Only type A was used in this investigation. Type A appears to have great muscle paralytic effect in humans.

Botulinum toxin therapy of strabismus is a medical technique in which botulinum toxin is injected into selected extraocular muscles in order to reduce the misalignment of the eyes. The injection of the toxin to treat strabismus, reported upon in 1981, is considered to be the first ever use of botulinum toxin for therapeutic purposes. Today, the injection of botulinum toxin into the muscles that surround the eyes is one of the available options in the management of strabismus. Other options for strabismus management are vision therapy and occlusion therapy, corrective glasses (or contact lenses) and prism glasses, and strabismus surgery.

The effects that are due only to the toxin itself (including the side effects) generally wear off within 3 to 4 months. In contrast, improvements in alignment may be long-lasting, particularly in two circumstances. First, if the "antagonist" muscle (the muscle pulling in the opposite direction) is active, the injected muscle will be stretched, and may permanently lengthen by adding tissue during the period of toxin paresis.[citation needed] Second, if binocular vision has been achieved and stabilized, alignment may "lock in". There are indications that botulinum toxin therapy is as successful as strabismus surgery for patients with binocular vision and that it is less successful than surgery for those who have no binocular vision.

Botulinum Toxin Injection for Blepharospasm by Dr Vidushi Sharma at SuVi Eye Kota India

In this video, Dr Vidushi Sharma & Dr Suresh K Pandey (SuVi Eye Institute, Kota India) demonstrate botulinum toxin injection to manage severe blepharospasm. Blepharospasm is a common eye condition that is characterized by spasms of the upper and/or lower eyelid that cause the eye to shut involuntarily. In some patients, severe and chronic blepharospasm can cause functional blindness, as the patient may be unable to keep his eyelids open. Botox/Botogenie has been used for decades to treat blepharospasm, and it is the treatment of choice .BOTOGenie® is a biologically active and highly purified preparation of Botulinum toxin Type A. This is an extremely potent neurotoxin complex which causes relaxation of muscles, marked reduction in sweat gland secretory activity and silencing of nociceptor function on its absorption. The medical science has developed methodology to derive magical drug effect by unique formulation and controlled administration techniques. It has been used to correct undesirable muscular activity for a considerable period without surgical intervention. This action is reversible in nature in a few months. Since BOTOGenie® is in a highly purified form & is used in minute quantities, it does not induce any immunological response even after several treatments in most subjects. BOTOGenie® has unique pharmacological properties as a neuromuscular blocking agent. It acts by inhibiting the release of acetylcholine resulting in partial & local inactivation of muscle activity. This effect usually lasts for 4-6 months when it needs to be redone. Thus it helps to reduce some of the diseased conditions caused by abnormal muscular contraction e.g. Hemifacial spasms, Cerebral Palsy etc. The action is dose related to large extent.This unique muscle relaxation property of Botulinum toxin Type A has been most exploited for cosmetic correction of facial defects ( due to contraction of group of muscles ) like Glabeller lines, Forehead skin folds, Crow feet effect near lateral side of eyes & other facial wrinkles. Marked reduction in sweat gland secretory activity (Hyperhydrosis-Palmer, Axilla) and silencing of nociceptor function for relief from pain (Migraine, Chronic pain, Neck pain etc.) have been achieved.Botulinum toxin Type A has been used with excellent results to correct the above diseased conditions and many more like Spasmodic dysphonia, Drooling saliva, Speech & Voice disorder, Achlasia etc.

Strabismus botox treatment , medial rectus muscle

Correction of esotropia via botox injection in the medial rectus muscle guided by EMG without general anesthesia and with minimal complications.

Strabismus botox correction, medial rectus under General anesthesia.

Treantment of Strabismus in a child done under General anesthesia. The procedure involves injection of botox in the medial Rectus muscle after conjunctival incision.

EMG guided Botox injection for Squint

This video demonstrates the technique of injecting BOTOX to correct strabismus (squint) in a 13 year old child using an EMG guided Injection technique.