A Comparison between the Lyra Long-Pulsed Nd:YAG laser system and the
Coherent LightSheer Diode laser system in the removal of hair
Roy Grekin, M.D.
Christopher Zachary, F.R.C.P.
Division of Dermatologic and Laser Surgery
University of California, San Francisco
The objective of this study was to compare the efficacy and safety of the two wavelengths – 1064nm and 810nm –
in the removal of hair in various skin types.
Material and Methods
A total of 46 identical sites were treated with two laser systems – 23 sites with the Lyra long-pulsed Nd:YAG laser
and 23 sites with the LightSheer 810nm diode laser. Patients underwent 3 treatments at 6 to 8 weeks intervals.
The final evaluation took place at six months and ten months post last treatment. All patients were evaluated by a
blinded investigator using high resolution photographs and by objective hair counts.
Both lasers were found to deliver very similar clinical results, with the exception that the Nd:YAG laser was found
safer on darker skin patients.
Laser epilation is one of the most popular and
commonly performed cosmetic procedures.
Introduced five years ago with the normal mode
Ruby (694nm) laser1, the procedure has
experienced radical changes. A variety of laser
wavelengths, application times, and surface
cooling methods have been since introduced4.
The biggest challenge with this procedure was
finding a single laser system that would treat all
hair colors and skin types2. The mechanism of
laser hair removal is based on light absorption
by follicular pigment, after having passed intact
through the skin pigment. As laser technology
developed, new wavelengths were introduced,
moving from the short-pulsed visible to the
long-pulsed infrared wavelengths. This
resolved some of the problems with the darker
skin types6,7. However, the question arose as to
commonly used wavelengths in the removal of
hair, given its relatively poor absorption in
melanin. Therefore, the objective of this study
was to compare the reduction of hair re