There are three FDA approved botulinum toxin type A’s on the market: Botox, Dysport and Xeomin. All are very effective in reducing rhytids, including in the periocular region. They all work via the same mechanism of action: to cleave SNAP-25 and prevent the release of acetylcholine into the neuromuscular junction.
Many say there are subtle differences between the three, but all are used in a similar manner. The only FDA approved cosmetic indication common to all is treatment of the glabellar region. In addition, Botox received FDA approval in September 2013 for the treatment of lateral canthal lines.
The most common area to inject is the glabella region. The clinical trials for this region were done using a 5-point injection (2 injections in each corrugator and one injection in the procerus). These injections in the glabellar region not only improve dynamic wrinkles, but also can provide a subtle medial brow lift at rest by weakening the depressor muscles. The second periorbital region of mention is the lateral canthal lines, or crow’s feet. By weakening the orbicularis oculi, vast improvement in these wrinkles can dramatically rejuvenate the eye area. This is a superficial injection because the muscle is directly beneath the thin skin. By staying just underneath the skin, one will avoid puncturing vessels leading to bruising and can avoid untargeted muscles, such as the zygomaticus, which will cause a crooked smile if weakened on one side.
In general, it is best to stay at least 1 cm lateral to the lateral canthus and not go past the mid-pupillary line. Crow’s feet injections should also be tailored depending on how wide the lines extend.
Injection of the frontalis muscle can dramatically alter the shape of the periocular region. One must take caution when injecting this area because too much toxin can cause the brows to droop with a resulting secondary dermatochalasis. There are many situations where this muscle should be avoided all together, such as in Asians who depend on this muscle to lift their lids, or people with preexisting dermatochalasis, brow ptosis or blepharoptosis.
To avoid problems, use small amounts, stay at or above horizontal midline of the forehead, and combine the frontalis with glabellar injections to counteract the net depression. Finally, injection into the lateral brow area, targeting the depressive action of the lateral orbicularis oculi, can create a ‘chemical brow lift’ by lifting the brow 1 – 2 mm. This injection can often be combined with a dermal filler for extra lift.
In a nutshell, neurotoxins can be used effectively to shape the periocular region. This option is non-invasive and offers patients a lunchtime procedure that can not only rejuvenate, but also prevent permanent wrinkles from forming.