Management of crow’s feet

Abstract

The crow’s feet are the wrinkles at the corners of the eyes due to contraction of the orbicularis oculi when smiling. The same part of the muscle is responsible for depressing the lateral part of the eyebrows and for resting tone at the side of the orbits, ‘supporting’ the face. The inferomedial part of the orbicularis muscle also works as a pump, to draw tears in to the lacrimal system when blinking. Unwanted side effects of botulinum toxin to this area include epiphora, sagging of the lower eyelid and deepening of the nasolabial folds. Careful examination will predict unsuitable patients who, because of the shape of their bone structure and/or level of resting skin tone, would be prone to such side effects. Other treatments to the rhytids may be offered instead, such as laser resurfacing of the skin. Treatment doses may be chosen to reflect the diffusion wanted.

Keywords

Botox, Dysport, crow’s feet, orbicularis oculi, laser skin resurfacing, sun damage.

‘Crow’s feet’ are the wrinkles that form with age at the outer corners of the eyes. They are due to contraction of the orbicularis oculi muscles ( Fig. 8.1 ). Their treatment with botulinum toxin is usually straightforward, but certain aspects must be considered carefully first.

The functions of the orbicularis oculi muscle are to close the eye, to drain the tear film and to create facial expressions. Contraction of this muscle can also drag on the lateral third of the eyebrow, contributing to drooping of the brow with age. In addition, the resting tension of the orbicularis oculi muscle can increase with age and character.

Many patients keep tension at the angle constant and so have pleasant ‘smiling eyes’. This tension can be important to the appearance of the patient: it results in rhytids but also supports an ageing midface in some patients. It can also prevent the protrusion of age-related lower lid ‘bags’ (orbital fat) by supporting the orbital septum.

Injections of botulinum toxin will smooth out the rhytids and make the skin look younger, but patients may begin to look ‘thin’ around their eyes as they lose muscle bulk after repeated injections. They may also look ‘drawn’ or tired as their midface falls over the zygomatic arch. Such changes usually do not become apparent until several treatments have been undertaken. The loss of tension can reverse with time because the orbicularis muscle rarely atrophies permanently; this has been shown by the results of long-term botulinum toxin treatment of orbital blepharospasm.

This chapter covers the assessment and treatment of crow’s feet. However, it is important to reexamine patients before every treatment and to make sure that they will still look well because of it. Make certain that the botulinum toxin can do for the patient what the patient expects.

Patient examination

• Examine patients both from the front and the side.

• Examine them at rest and when smiling.

• Try to imagine what relaxation of their orbicularis muscle will do to their appearance.