With the advancement of technology, non-ablative fractional laser (NAFL) has become one of the important means of treating skin photoaging. In particular, the two wavelengths of 1550 nm and 1565 nm non-ablative fractional laser have attracted much attention due to their high safety and short recovery period. However, are there any differences in the treatment effects of these two lasers? How do they perform in patients of different age groups? Today, we will combine two studies to explore these issues in depth.

SCIENTIFIC THEORIES

Principle of non-ablative fractional laser

In 2004, Professor Anderson's team proposed the principle of "focal photothermal effect" to explain the mechanism of action of fractional laser. This technology stimulates collagen regeneration and remodeling by forming a tiny thermal damage zone (MTZ) on the skin, thereby improving skin texture and wrinkles. The 1550 nm non-ablative fractional laser is a prototype developed based on this principle.

Fractal lasers are divided into ablative and non-ablative. Although ablative fractional lasers have significant effects, they are not suitable for Asians due to problems such as long wound healing time and easy to leave pigmentation. Non-ablative fractional lasers are an ideal choice for Asians because of their high safety and short recovery period.

1550 nm vs. 1565 nm: Clinical research comparison

2010 Korean study

In 2010, Korean scholars published a study comparing 1550 nm and 1565 nm non-ablative fractional lasers for the treatment of periorbital wrinkles. The study used a device produced by Lutronic, a Korean company, and 20 patients received treatment every 3 weeks for a total of 5 times. The parameters of the two lasers were the same (15–18 mJ, 500 spots/cm²), and the efficacy evaluation and histopathological examination were performed 3 months after the last treatment.

Research results:

Clinical effect: Both lasers showed significant effects in treating periorbital wrinkles, but there was no significant difference between the two. The wrinkle score before treatment was 3.75 ± 0.64, which dropped to 3.00 ± 0.79 3 months after treatment.

Figure 1: Comparison of the efficacy of two fractional lasers on the side of the face

A, B, C: Comparison of 1550nm fractional laser treatment of periorbital wrinkles before and after 1 month and 3 months

D, E, F: Comparison of 1565nm fractional laser treatment of periorbital wrinkles before and after 1 month and 3 months

Figure 2. Histopathological findings of periocular skin before and after treatment with 1550 nm and 1565 nm erbium glass laser, hematoxylin-eosin staining (magnification ×200).
(Before treatment with 1550 nm erbium glass laser (A) and 3 months after treatment (B); before treatment with 1565 nm erbium glass laser (C) and 3 months after treatment (D)).

Patient satisfaction: The patient satisfaction rates of 1550 nm and 1565 nm lasers were 40% and 45%, respectively, with 1565 nm being slightly higher.

Histopathological manifestations: Both lasers can significantly improve the elastic fiber and collagen fiber problems caused by skin aging. After treatment, the epidermis thickens and the elastic fibers return to normal arrangement.

Water absorption coefficient: The water absorption coefficient of 1565 nm is 0.2 orders of magnitude lower than that of 1550 nm, which means that the penetration depth of 1565 nm is slightly deeper.

Adverse reactions: About 30% of patients develop bronze skin, which is a temporary darkening of the skin color caused by the discharge of epidermal necrotic microfragments (MEND).

2024 Chinese Study

In 2024, Chinese scholars published a prospective, split-face randomized controlled study comparing the effects of 1550 nm and 1565 nm non-ablative fractional lasers in the treatment of periocular photoaging in different age groups. The study was divided into two groups: Group A (<45 years old) and Group B (≥45 years old), 9 people in each group, a total of 18 patients. Each group of patients received 1550 nm and 1565 nm laser treatments, 6 weeks apart each time, for a total of 3 times.

Research results:

Treatment effect: Six months after treatment, the periocular wrinkle depression score and volume of Group B (middle-aged and elderly patients) were significantly improved, while the improvement of Group A (young patients) was not significant.

Figure (B) Comparison of baseline and 6-month treatment effects before and after 1550 nm non-ablative fractional laser (NAFL) treatment in a 36-year-old woman in Group A.

Figure (C) Comparison of baseline and 6-month treatment effects of a 53-year-old woman in group B before and after 1550 nm non-ablative fractional laser (NAFL) treatment.

Comparison between the two groups: Group B was superior to Group A in improving periorbital photoaging, especially in the outer canthus and lower eyelid area.

Comparison of the two lasers: There is no significant difference in the therapeutic effect between 1550 nm and 1565 nm lasers, both of which can effectively improve periocular photoaging.

Adverse reactions: The treatment was well tolerated, with only mild and transient erythema, edema and pigmentation, and no infection, scarring or long-term adverse effects.

RESEARCH AND ANALYSIS

Combined analysis of two studies

Efficacy differences

Both studies showed that 1550 nm and 1565 nm non-ablative fractional lasers were effective in treating periocular photoaging, and there was no significant difference between the two. However, the patient satisfaction of 1565 nm was slightly higher in the Korean study, which may be related to its deeper penetration depth.

Age factors

The Chinese study found that the treatment effect of middle-aged and elderly patients (≥45 years old) was better than that of younger patients (<45 years old). This may be because the periocular skin of middle-aged and elderly patients is thinner and looser, and has accumulated more photodamage and collagen loss, so there is more room for improvement after treatment.

Adverse reactions

No serious adverse reactions were found in either study, but about 30% of patients in the Korean study developed bronze skin, which is a temporary pigmentation caused by MEND excretion. This phenomenon has also been verified in subsequent studies, indicating that non-ablative fractional lasers are safer.

Influencing factors

The efficacy of laser depends not only on wavelength and penetration depth, but also on energy and dot spacing (MTZ density). In theory, the higher the energy and the denser the dot spacing, the better the effect, but the incidence of adverse reactions will also increase. Therefore, in practical applications, parameters need to be adjusted according to the specific conditions of the patient.

SUMMARY

Summary

Non-ablative fractional lasers (1550 nm and 1565 nm) are effective treatments for periocular photoaging, especially for middle-aged and elderly patients. There is no significant difference in the therapeutic effect between the two lasers, but 1565 nm may be slightly better in some aspects. For younger patients, other treatments (such as injections and phototherapy) may be needed to achieve the best results. If you are interested in non-ablative fractional lasers, it is recommended to consult a professional doctor and choose the most suitable treatment plan according to your own situation.

References

1.Jung J Y, Cho S B, Chung H J, et al. Treatment of periorbital wrinkles with 1550‐and 1565‐nm Er: glass fractional photothermolysis lasers: a simultaneous split‐face trial[J]. Journal of the European Academy of Dermatology and Venereology, 2011, 25(7): 811-818.

2.Ximeng Jia, Heng Zheng,Lvping Huang,et al.Prospective, Split-Face Randomized Clinical Trial Comparing Non-ablative Fractional Laser for Periorbital Photoaging in Different Age Groups.2024

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