Laser Treatment of Dyschromia With a Novel 607 nm Pulsed-Dye Laser

April 2011 | Volume 10 | Issue 4 | Original Article | 388 | Copyright © 2011

Eric F. Bernstein MD MSE,a Jay Bhawalkar PhD,b Joan Clifford MS,b James White,b James Hsia PhDb

aMain Line Center for Laser Surgery, Ardmore, PA
bCandela Corporation, Wayland, MA

Abstract

Background: Due to the hemoglobin-selective wavelength of the 595 nm pulsed-dye laser, it is a device of choice for treating cutaneous vascular lesions. However, it is less effective and removing dyschromia, which along with hypervascularity is a cardinal sign of cutaneous photodamage. A novel 607 nm dye laser was developed as a first step in creating a dual-wavelength pulsed-dye laser.
Study Design/Materials and Methods: Twenty-five subjects with dyschromia on the chest due to chronic photodamage were enrolled into an open-label study to explore the safety and efficacy of a 607 nm pulsed-dye laser, with 22 completing the study. Two treatments were administered to the chest, one month apart, with fluences ranging from 3-6 J/cm,2 using a 10 mm diameter spot and pulse duration of 1.5 msec. Cross-polarized digital photographs were taken before and two months following the final treatment and rated for improvement by physicians in a blinded fashion.
Results: Improvement was rated on a five-point scale with no subjects rated as poor (<25%) clearance, three subjects (13.6%) demonstrating fair (26-50%) improvement, seven subjects (31.8%) rated as good (51-75%) improvement, 12 (54.5%) were rated as excellent (76-95%) improvement, while none were rated as outstanding improvement (>95%).
Conclusion: This is the first study of the 607 nm pulsed-dye laser which showed it to be safe and effective for treating dyschromia of the chest due to chronic photodamage, and may in the future expand the ability of the pulsed-dye laser to treat photodamaged skin.

J Drugs Dermatol. 2011;10(4):388-394.

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INTRODUCTION

The majority of changes we associate with aging are the results of chronic photodamage and include five main features: fine lines and wrinkles, enlarged pores, sagging skin, telangiectasias and dyschromia in the form of ephelides and solar lentigos.1-4 The pulsed-dye laser (PDL) has been shown to improve photodamaged skin through a variety of mechanisms and addresses most of the features of photodamage, 5-11 but not nearly to the same degree. Because the 585-595 nm wavelengths most commonly available from PDLs are so strongly absorbed by hemoglobin, the telangiectatic and erythematous components of photoaging are by far the most susceptible to PDL treatment. Melanin pigment absorbs very broadly from the ultraviolet end of the solar spectrum, through the visible and into the infrared spectrum, generally with decreasing absorption as the wavelength of radiation increases beyond the ultraviolet end of the spectrum. Absorption in the 585-595 nm range is substantial, and should be quite effective at treating unwanted pigmentation such as ephelides and solar lentigos. However, treatment with sufficient fluences to destroy pigmented lesions at pulse-durations similar to those used with intense pulsed light sources (IPLs), in the 1.5-3 ms range, results in significant purpura, an unacceptable side-effect. In addition, hemoglobin absorption of incident laser energy at these wavelengths prevents much of the incident laser energy entering the skin from exiting and treating the epidermal pigment a second time on the way out of the skin (2nd-pass effect).11,12-14 Longer pulse durations of 10 ms or greater do not result in purpura at most fluences high enough to treat dyschromia, however, treatment-limiting edema often makes using these longer pulse-durations to treat pigmentation on the face without epidermal cooling unpractical. Higher fluences are generally required to get similar effects removing pigment when using longer pulse-durations with the PDL.

IPLs are quite effective at treating dyschromia but have some significant limitations compared to the PDL. Because much of the incident energy is outside of the absorption peaks of hemoglobin, treatment of erythema with IPLs is less predictable than with PDLs and generally less effective, since most of the 595 nm PDL laser energy goes into doing work of heating unwanted blood vessels, while much of the energy emitted from an IPL is not taken up significantly by blood vessels. In addition, IPLs have the disadvantage of delivering large spot sizes and long

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