A, Treated side, 2 months after 4 treatments with a long-pulse 532-nm laser (DioLite Laser; Iridex, Mountain View, Calif). B, Untreated control side (photograph taken at the same time as the photograph of the treated side).
Paul J. Carniol, Sarah Farley, Adam Friedman. Long-Pulse 532-nm Diode Laser for Nonablative Facial Skin Rejuvenation. Arch Facial Plast Surg. 2003;5(6):511–513. doi:10.1001/archfaci.5.6.511
From the Section of Otolaryngology, Department of Surgery, University of Medicine & Dentistry of New Jersey, Summit.
Objective To evaluate the efficacy of a long-pulse 532-nm frequency doubled Nd:YAG laser for nonablative facial skin rejuvenation.
Methods Patients received a series of treatments to one side of their periorbital and midfacial region. The opposite side was not treated, and served as a control. An evaluation of the results was performed by the patients and by single-blinded review of digital photographs.
Results The patients involved in the study all noted an improvement in their appearance. The single-blinded observers noted a significant improvement in 5 (71%) of the 7 patients. On average, these patients had a 25% improvement in their appearance.
Conclusions In this preliminary study, the long-pulse 532-nm Nd:YAG laser was effective for the treatment of photoaging. The patients were pleased with the results, particularly because they were able to obtain an improvement in appearance with minimal discomfort and without any loss of time from their regular activities.
SINCE THE introduction of high-powered pulsed carbon dioxide lasers for ablative wrinkle reduction and treatment of photoaging in the mid 1990s, laser resurfacing has become the standard of treatment for facial skin rejuvenation. Initially, this technique was popular. Although the results are impressive, the discomfort, prolonged recovery time, and high risk of complications led to patient dissatisfaction and a gradual decline in the popularity of this technique. Although the carbon dioxide laser remains the treatment of choice for severely photodamaged skin, nonablative skin rejuvenation can improve the appearance of lines and wrinkles for mild to moderately photodamaged skin with a minimal risk of complications and without the downtime associated with ablative resurfacing techniques. As laser technology has progressed, several nonablative lasers for facial rejuvenation have become available. The results of treatment with these lasers have been reported by several researchers.1-6
The actual mechanism by which nonablative skin rejuvenation improves the appearance of wrinkles is not completely understood. It is believed that absorption by targets in the epidermis and dermis stimulates the secretion of growth factors that stimulate the production of collagen.
The ideal nonablative technology should meet the following criteria: no significant recovery time, minimal discomfort during the treatment, an observable improvement in the appearance of rhytids, and an improvement in the appearance of the skin.
Evaluating the results of nonablative laser treatments presents an interesting dilemma. As reported by Trelles et al,1 a histologically identifiable increase in collagen may not correlate with a noticeable clinical improvement and patient satisfaction. Based on this observation, the most important criterion for assessing the results of nonablative skin rejuvenation should be an observable improvement by the patients and by independent observers. Therefore, in this study, the results of the laser treatments were evaluated by the subjective criteria of single-blinded observers and by patient evaluations.
The 532-nm laser is selectively absorbed by melanin in the epidermis and oxyhemoglobin in the blood. The 532-nm laser can potentially provide a nonablative improvement in the appearance of the facial skin by 3 mechanisms that have been postulated. The first is that this laser treats facial telangiectases and pigmented lesions, improving the tone and evenness of the skin. The second is that laser treatment of the skin can cause a decrease in Demodex and, thereby, decrease the pore size.7 The third is that the endothelial injury induced by this laser causes a cytokine release. This results in the formation of new collagen and elastin fibers.7
With this in mind, we designed a protocol using a long-pulse 532-nm laser (DioLite Laser; Iridex, Mountain View, Calif) with a scanner (ScanLite; Iridex). This laser has been used extensively for the treatment of vascular and pigmented lesions8; to our knowledge, it has not been used for nonablative facial skin rejuvenation.
Eight women with Fitzpatrick skin types II and III, between the ages of 35 and 52 years, were enrolled into this study, after giving their informed consent. The mean age of the participants was 46 years. Two of the participants smoked cigarettes. The laser treatment was performed on half of the midfacial and periorbital region. The other side was not treated so that it could serve as a control. The side to be treated was selected randomly. Each patient received 4 laser treatments at monthly intervals. One patient was unable to complete the study because of the onset of unrelated medical problems.
Each treatment was performed using the 532-nm Nd:YAG laser and the scanner. The scanner was used to ensure a rapid consistent pattern of application of energy to the treated areas. Before treatment was initiated, a limited area of preauricular skin was used for test scans, to determine the maximum fluence without inducing prolonged erythema or blistering. The system was set to 3 W; the fluence was in the range of 10 to 14 J/cm2. The pulse duration varied from 13 to 17 milliseconds. The repetition rate was set at 25 Hz.
The scan was performed with a 20% spread between the 700-µm spots produced by the scanner. This 20% spread allows for a collateral skin-cooling effect from the adjacent untreated skin within the scanned area. The epidermis was further cooled during the perilaser period by applying refrigerated aloe vera gel. Standard laser safety precautions were maintained at all times.
Following the treatment, the treated area was covered with a new layer of aloe vera gel. Patients were asked to leave the gel in place for at least 2 hours after treatment.
Digital photography was performed before each treatment and 2 months following the final treatment.
After the treatments were completed, patients and 2 single-blinded observers were asked to complete evaluation forms measuring their impression and level of satisfaction with the results. The observers reviewed the patients' digital photographic images and were asked to identify which side was treated. They were also asked to describe the type of change that they observed and to qualitatively assess the result using a rating scale of 0 to 4 (0 indicated a worsening of the condition; 1, no improvement; 2, mild improvement; 3, moderate improvement; and 4, marked improvement). The patients were also asked to assess their result using the same scale.
All of the patients who completed the study reported a noticeable improvement and were pleased with the results. The improvement varied from improved skin texture in one patient to diminished dyschromia in another, to an improvement in skin smoothness and decreased rhytids in 5 of the 7 patients. Their average assessment of the change in appearance of the treated side was a 2, indicating mild improvement. They noted no change in appearance or texture of the untreated side.
All 7 of the patients reported only minimal discomfort during the procedure. No anesthesia was necessary.
Typically, the patients had only some mild erythema after each procedure, which resolved in 1 to 4 hours. No adverse events were noted. All of the patients were able to resume their regular activities as soon as each treatment was completed. All of the patients were willing to undergo additional treatments to try to obtain further improvement.
The single-blinded observers were able to identify which side of the face had been treated in the 5 patients who had an improvement in skin smoothness and decreased rhytids (Figure 1 and Figure 2). No change in appearance was noted on the untreated side. They were not able to identify which side had been treated in the patient who had diminished dyschromia and in the patient who had only a textural improvement. Their average rating of the change in skin appearance on the treated side was a 2.
In this study, the long-pulse 532-nm diode laser was effective, within limitations, as a nonablative treatment for skin rejuvenation. All of the patients reported a noticeable improvement. The overall improvement obtained was mild, and not as dramatic as that typically obtained with ablative laser resurfacing.9-15 However, all of the patients in this study would not consider undergoing an ablative resurfacing procedure because of the typical course of postresurfacing recovery.
The single-blinded observers were able to identify a noticeable improvement in 5 of the 7 patients.
The issue of patient satisfaction is important. In this study, all 7 patients believed that they had a noticeable improvement. It was easy for them to compare the results because one side of their face was not treated. The patients also expressed a desire to continue with further laser treatments, if they could derive further benefit. The patients were also pleased because there was only minimal discomfort and mild erythema (lasting, at most, only a few hours) associated with the laser treatments.
Because this study was an evaluation of the effectiveness of this treatment, none of the patients were charged for the laser procedures. It is possible that this could have introduced a favorable patient bias because this may have lowered their expectations.
Further evaluations of this laser for nonablative skin rejuvenation are continuing. One issue is as follows: Will there be further improvement during subsequent months after treatment, as described with other lasers?
Other related issues include the following: Can further improvement be obtained with additional treatments? How would the response vary if a different protocol is used? How do the results of treatment with this laser compare with the results of treatment with other nonablative lasers or with intense pulsed light? These and other questions require further evaluation.
Corresponding author: Paul J. Carniol, MD, University of Medicine & Dentistry of New Jersey, 33 Overlook Rd, Suite 202, Summit, NJ 07901.
Accepted for publication June 9, 2003.