Diplopia: double vision and its relationship to toxin

Diplopia is the perception of two images of the same object, known as double vision. It can be monocular (it persists with only one eye open, usually because of the eye itself) or binocular (it goes away when one eye is closed, usually because of misalignment between the eyes). In orofacial harmonization, the term matters for two very different reasons: one relatively benign, tied to botulinum toxin, and one serious, tied to fillers.

How can toxin lead to diplopia?

Around the eye there are small muscles that move the eyeball. If toxin injected in the forehead, glabella, or periorbital region diffuses to them, weakness in one of those muscles can misalign the gaze and cause binocular double vision. It is a rare event, generally transient, that follows the recovery from the toxin's action.

Neighboring conditions can also appear, such as eyelid ptosis, when the toxin reaches the muscle that lifts the eyelid. Prevention involves knowing the anatomy, choosing volume and site carefully, and instructing the patient on aftercare.

And when diplopia appears after filler?

Here the reasoning changes. Double vision, blurring, severe eye pain, or vision loss right after filler in the glabella, nose, or periorbital region should be treated as possible vascular occlusion with compromised circulation to the eye. It is not an expected effect and it does not wait to "pass on its own."

What should you ask at the consultation?

• Have you ever had double vision, strabismus, or eye surgery?
• Do you wear glasses or have any neuromuscular disease?
• Do you understand what to do, and whom to contact, if you notice a change in vision?

Explaining the warning sign before the injection is part of informed consent and protects the patient.

In Harmy

The Glabella and Tear Trough points are in areas next to the eye. The projection helps in talking about what will be treated, but it does not replace the clinical assessment of the risks in the area.

Also called: double vision.