Effect of fractional picosecond laser therapy using a diffractive optical lens on histological tissue reaction

Fractional ablative resurfacing techniques are preferred treatments for facial rejuvenation of aged skin. This study was performed to investigate the cutaneous effects of using a fractional picosecond laser at 1064 nm with a diffractive lens. The penetration depth according to the location of the handpiece tip was evaluated using an acrylic panel. Laser induced optical breakdown (LIOB) and cutaneous damage were observed after hematoxylin and eosin staining in guinea pigs. Collagen formation was evaluated using Victoria staining, Masson’s trichrome (MT) staining, and immunohistochemical staining for collagen type III. The penetration depth for LEVEL 1 was 499.98–935.23 μm (average: 668.75 ± 182.84 μm); the LIOB cavity area was 1664.17 ± 650.52 μm². The penetration depth of LEVEL 2 was 257.12–287.38 μm (average: 269.77 ± 14.55 μm) with an LIOB cavity area of 1335.85 ± 214.41 μm². At LEVEL 3, that was 36.17–53.69 μm (average: 52.15 ± 20.81 μm) and the LIOB cavity area was 1312.67 ± 1069.12 μm². No epidermal tissue damage was observed and collagen formation was observed from day 14 under all conditions. Diffractive optical element (DOE) lens arranged laser treatment system controlled the position of LIOB occurrence and an irradiating area.