How to avoid lateral rectus palsy and double vision from Botox treatment

Botulinum toxin or Botox® injections are commonly performed around the eyes for cosmetic wrinkle relaxation of the crow’s feet; however, aesthetic clinicians must always be mindful of protecting patients from potential negative side effects when delivering these facial aesthetic treatments.

We recently explored how to avoid causing eyelid ptosis with botulinum toxin treatments. Although greatly feared, an eyelid droop is not the only complication that may affect the periocular area and eyes. To safely perform upper face and periocular botulinum toxin injections, you must master essential anatomical understanding and injection techniques that allow you to focus on preventing complications like double vision caused by lateral rectus palsy.

In this blog, Dr Tim Pearce will discuss relevant anatomy around the eye, highlighting key structures using 3D anatomy tools, share optimal injection depths and spacing strategies to protect sensitive eye muscles, give you practical steps for safe and effective results, and help you avoid common pitfalls with periocular Botox treatments.

Double vision from Botox, a complication caused by affecting the lateral rectus muscle

The lateral rectus muscle is another important muscle around the eye that can be inadvertently affected by botulinum toxin injections.

It pulls the eye laterally, away from the midline. Each time a person looks left or right, the left or right lateral rectus muscles pull the eye in that direction. If you weaken one of the muscles, as they look left or right, the unaffected eye will move but the eye that is affected will stay in the same position, leading to immediate double vision. This is a known and reported side effect of treating the lateral canthal lines (crow’s feet) with botulinum toxin when the injections have been placed too close to the eye.

The lateral rectus muscle often protrudes very close to the orbital rim. Placing a needle directly into this area to deliver a dose of botulinum toxin would result in a high likelihood of affecting the insertion point of the lateral rectus muscle, but its location also makes it eminently avoidable. Treating the orbicularis oculi muscle could affect the lateral rectus muscle; however, a good injection technique will reduce the risk significantly.

It is noteworthy that the original discovery of the cosmetic benefits of botulinum toxin was made in the mid-1980s by the ophthalmologist and dermatologist partnership of Drs Jean and Alistair Carruthers, the husband and wife shared a clinic and were using the drug to treat blepharospasm when patients started to report improvements in upper facial wrinkles. From its inception in aesthetic medicine, we have witnessed that botulinum toxin can spread and affect nearby muscles, both beneficially and adversely.

Safety margins and injection strategies to reduce the risk of botulinum toxin spread

You can reduce the risk of causing lateral rectus palsy and double vision by using several injection strategies and safety measures.

The depth of injection is a key factor.

When treating lateral canthal lines, the approach is to treat the orbicularis oculi muscle, a superficial muscle found underneath a thin layer of skin.

For the best injection technique, slide the needle 1 to 2mm into the skin, just beyond the point where the skin blanches. When you inject, this will create a small bleb of botulinum toxin that will sit on the surface of the orbicularis oculi muscle, and act as a defence against the toxin going deeper into the underlying ocular structures.

Under the orbicularis oculi muscle is a layer of fat before the bone, plus the orbital membrane, depending on where you are injecting. These layers protect the other important ocular structures when injecting; but, if you go too deep, you effectively slice through all the layers, increasing bruising and significantly increasing the risk of an adverse outcome.

Proximity to the orbital rim is another key factor.

The best defence against spreading botulinum toxin too deeply into the ocular area, and to avoid affecting the lateral rectus muscle, is having a bone in the way. In this instance, the bone is the orbital rim. The closer you get to the orbital rim with your injection placement, the more likely you will spread botulinum toxin beyond that point, and risk compromising the lateral rectus muscle.

For the best injection technique, leave a 1.5cm margin of safety back from the orbital rim and aim to point your needle away from the eye when injecting; certainly, until you are a more confident injector and have more experience with needle tip control. Newer aesthetic injectors often slide the needle beyond the point where they want to inject, going in too far towards the eye, and then pulling back a little before injecting the product. This action leaves a needle tract which allows botulinum toxin to spread beyond the safety margin.

Download a free guide from Dr Tim Pearce on how to avoid causing lateral rectus palsy from botulinum toxins. The guide provides actionable insights for both new and experienced aesthetic clinicians to ensure patient safety and high-quality outcomes in periocular Botox treatments.

Dr Tim shares further insight on safe Botox injection points for crow’s feet and what can go wrong when treating orbicularis oculi with Botox.

Remember, if you have any questions or topics for discussion, you can find Dr Tim Pearce on Instagram.

Introducing Pro Tox

If you have been waiting to stop second-guessing yourself during botulinum toxin treatments, deliver flawless results that keep patients coming back, unlock advanced techniques, minimise complications, and finally feel like the expert injector you know you can be; find out more about the Pro Tox system from Dr Tim Pearce.

With Pro Tox, you will have the tools and comprehensive training to deliver consistently flawless results that keep your patients loyal, happy, and referring their friends – without needing review appointments or competing on price.

Botox® is a registered trademark of Allergan Aesthetics plc.

Aesthetics Mastery Show

3-Minute Guide: Botox Injection Tips to Avoid Double Vision Complications

In this episode, Dr Tim will teach you essential techniques for safely performing botulinum toxin injections around the eyes, with a focus on preventing complications like double vision caused by lateral rectus palsy. You’ll learn about key anatomy, optimal injection depths, and spacing strategies to protect sensitive eye muscles. Whether you’re new or experienced, Dr. Tim shares practical steps to ensure safe, effective results and help you avoid common pitfalls in periocular treatments.

Watch the full Aesthetics Mastery Show here.

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BOTOX (Botulinum Toxin) eLearning Courses

If you want to increase your confidence in botulinum toxin injections, or learn how to avoid and handle complications, Dr Tim Pearce offers two comprehensive courses that are highly rated by our delegates:

• BOTOX® Foundation Course
• Botulinum Toxin Complications Mastery

Both give CPD and certificates on completion.

In addition, browse our FREE downloadable resources on complications.

Dr Tim Pearce eLearning

Dr Tim Pearce MBChB BSc (Hons) MRCGP founded his eLearning concept in 2016 in order to provide readily accessible BOTOX® and dermal filler online courses for fellow Medical Aesthetics practitioners. His objective was to raise standards within the industry – a principle which remains just as relevant today.

Our exclusive video-led courses are designed to build confidence, knowledge and technique at every stage, working from foundation level to advanced treatments and management of complications.

Thousands of delegates have benefited from the courses and we’re highly rated on Trustpilot. For more information or to discuss which course is right for you, please get in touch with our friendly team.