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Botulinum A toxin (BOTOX) in the lower eyelid: dose-finding study.
Timothy Corcoran Flynn1, Jean A Carruthers, J Alastair Carruthers
1Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. flynn@caryskincenter.com
Summary
Botulinum toxin type A (BTX-A) effectively treats lower eyelid wrinkles and widens the eye. Higher doses increase eye widening but also side effects, suggesting lower doses are optimal for infraorbital wrinkles.
Area of Science:
- Dermatology
- Aesthetic Medicine
- Ophthalmology
Background:
- Botulinum toxin type A (BTX-A) is a recognized treatment for hyperkinetic facial lines, including periocular wrinkles.
- BTX-A improves wrinkles by relaxing underlying facial muscles.
- It is effective for lateral orbital (crow's feet) wrinkles and can be used in the lower eyelid to improve wrinkles and widen the eye.
Purpose of the Study:
- To evaluate the efficacy of higher doses of BTX-A for infraorbital wrinkles and eye widening.
- To determine if doses exceeding 2 units of BTX-A in the lower eyelid offer additional aesthetic benefits.
Main Methods:
- Nineteen women received BTX-A injections into the orbicularis oculi muscle.
- Two dosage groups were studied: 4 U in the lower eyelid (bilaterally) and 8 U in the lower eyelid (bilaterally), with 12 U in the lateral orbital area for both groups.
- Improvements were assessed by physicians and patients using a grading scale, and palpebral aperture increase was measured in millimeters.
Main Results:
- Both physicians and patients reported wrinkle improvement with BTX-A in the lower eyelid at both 4 U and 8 U doses.
- Treatment of the lateral orbital area combined with the lower eyelid showed synergistic effects at lower doses.
- Increased doses of BTX-A led to greater eye widening, but higher doses (8 U) were associated with increased side effects like edema.
Conclusions:
- A dose-response relationship exists for BTX-A in the lower eyelid.
- Combining lower lid and lateral orbital treatment offers benefits, but higher doses may plateau.
- Lower doses (2-4 U) of BTX-A are recommended for the lower eyelid to balance efficacy and minimize side effects.