Dry eyes after Botox: why, how long and what to do

An eye that stings, burns, feels gritty or, paradoxically, waters: dry eye is one of the problems around the eyes after a botulinum toxin injection. It occurs mainly after treatment of crow’s feet, at the corners of the eyes. It is usually mild and temporary. But the eye is a delicate organ: significant dryness, pain or reduced vision should prompt you to see a doctor promptly. This page answers the seven questions people ask most often.

Why does the eye become dry after an injection?

The muscle injected to soften crow’s feet, the orbicularis oculi, is also the muscle that closes the eyelids. With every blink, it spreads tears over the surface of the eye and helps renew them. If it is too relaxed, blinking becomes less effective.

The label of a botulinum toxin describes this mechanism: reduced blinking, reported with botulinum toxins, can lead to dry eye, exposure of the cornea and, in the most severe cases, damage to its surface, especially in people with a disorder of the facial nerve³. A review of upper face complications adds that paralysis of the orbital part of the muscle can prevent the eye from closing fully, which dries it out⁴.

Recent studies suggest other effects on tears. In 30 patients treated for crow’s feet, the tear film was less stable and the small glands along the edge of the eyelids, which produce the oily part of tears, worked less well in the three months after the injection⁵. In another study, basal tear production was lower in people who had recently had injections around the eyes, with no clear difference in reported symptoms⁶.

The labels classify this effect differently: dry eye is common after treatment of crow’s feet with one type A toxin, and uncommon after treatment of the whole upper face¹. For another type A toxin, it has been reported since the product was marketed, with no known frequency².

How soon after the injection does it appear?

No label specifies a time to onset. In the study of 30 patients treated for crow’s feet, superficial damage to the cornea was most marked one week after the injection, whereas tear film stability was lowest at three months⁵. Dryness can therefore appear in the first few days, as the effect of the toxin builds up, or be felt later.

How long does it last?

It generally lasts as long as the muscle stays relaxed, that is, as long as the product’s effect. For crow’s feet, one type A toxin showed an effect on lines for up to 5 months in trials². The authors of the study on the eye surface conclude that these changes are temporary⁵. Durations of effect for each product are explained on the page about how long botulinum toxin lasts.

Is it reversible?

Yes. Adverse effects of botulinum toxin in the upper face are described as transient⁴, and the authors of the study on the eye surface describe the changes as temporary⁵: when the orbicularis muscle regains its strength, blinking becomes effective again. The label stresses, however, that damage to the cornea must be treated vigorously³: this is why significant dryness should not be ignored.

Is there a treatment?

Yes. If the eye does not close fully and becomes dry, lubricating eye drops and gels are recommended⁴. When the surface of the cornea is damaged, the label of a botulinum toxin calls for vigorous treatment, which may involve protective drops, ointment, therapeutic soft contact lenses or closing the eye with a patch³. These treatments are decided after an examination, usually by an ophthalmologist.

Simple measures often help: taking breaks from screens, avoiding dry air or direct air-conditioning draughts, protecting the eye at night if it does not close properly. No treatment makes the toxin wear off faster.

What should you avoid?

Do not rub your eyes: a dry cornea is more fragile. Do not use any eye drops other than a lubricant without medical advice, and in particular no over-the-counter "anti-redness" drops. Do not let pain or reduced vision drag on. Do not schedule another injection around the eyes while the dryness persists, and mention it to the doctor before your next session.

When should you see a doctor?

Talk to the doctor who performed the injection if your eye is dry, even moderately, so that they can check that your eyelids close properly. See a doctor promptly, ideally an ophthalmologist, if the eye is red and painful, if light bothers you, if you cannot close your eye fully, if the feeling of something in the eye persists or if your vision gets worse: these signs may point to damage to the cornea³.

Dry eyes often go with crow’s feet that look overdone. Other effects can affect the same area: puffy eyelids or an eyelid that droops.