Variables that predict response of nevus of ota to lasers

Abstract

Nevus of ota (also known as oculodermal melanocytosis or nevus fuscoceruleus ophthalmomaxillaris) is a mottled, blue-gray macule that is usually located unilaterally within the distribution of the first and second branches of the trigeminal nerve. Nevus of ota (NOA) is congenital in about 50% of cases, while in other cases it appears by the second decade of life. 1 Acquired nevus of ota-like macules (also known as Hori's nevus) differ from the classic nevus of ota in that they are bilateral, spare mucosa, and occur later in life. 2 | RELE VANT L A S ER-TISSUE INTER AC TI ON SThe ability of laser and light sources to diminish pigmented lesions is based on the principle of selective photothermolysis which had predicted that for selective thermal damage to an absorbing target, the correct laser wavelength, and appropriate pulse duration relevant to the target organelle must be ensured. For this, the wavelength should correspond to the absorption characteristics of the target, the pulse duration should be shorter than the thermal relaxation time and in case of NOA should have a deep penetration. 3 Here, the target is the melanosomes for which a Q-switched (QS) mode is ideal. 4,5 Other lasers that can be used include the pulsed tunable dye laser (wavelength 435-750 nm, pulse width 300-750 ns), 6,7 Q-switched ruby laser (QSRL;wavelength 694 nm, pulse width 40 ns), 5 and the Q-switched Nd:YAG(neodymium-doped yttrium aluminum garnet; wavelength 355, 532, and 1064 nm, pulse width 10-12 ns). 8 Anderson et al performed a study using 12 ns Q-switched Nd-YAG (neodymium-yttrium-aluminum-garnet) laser pulses at 355, 532, and 1064 nm in pigmented and albino guinea pig skin. At each wavelength, melanosomes were ruptured within keratinocytes and melanocytes, with cytoplasmic and nuclear alterations. 8Selective injury to melanosomes and pigmented cells occurs after 351 nm (15 ns duration) ultraviolet laser pulses, 4,9 or 694 nm (40 ns duration) red pulses from a Q-switched ruby laser. 5,10 For these wavelengths, absorption by melanin dominates over that by blood, 11 and the site of primary injury appears to be melanosomes. While shorter wavelengths, such as 351 nm are better at absorbed by melanin, longer wavelengths penetrate deeper into the skin, increasing their ability to reach the deeper melanosomes. | IDE AL L A S ERWhile the QSRL has been the most widely used laser for NOA, [12][13][14] the Q-switched alexandrite (QSA) 15 and QS Nd: YAG lasers are as effective as compared to Q-switched ruby laser. As the QSRL has a higher absorption spectrum for melanin, it can lead to pigmentary SummaryNevus of ota is a dermal melanocytosis common among Asian patients, mottled, blue-gray macule that is usually located unilaterally within the distribution of the first and second branches of the trigeminal nerve and almost always responds well to treatment with Q-switched lasers (eg, ruby, alexandrite, and Nd: YAG). In spite of the plethora of science behind laser-tissue interactions, the objective evaluation of nevus of ota response to la...

Treatment of nevus of Ota with 1064 nm picosecond Nd:YAG laser: A retrospective study

“…PIH was observed only in one (1/16, 6.25%) patient in our research, this incidence was similar to QSNL (pooled adverse event rate: 5%) and lower than other Q‐switched lasers and PSAL 4 . The observed higher safety of PSNL is likely caused by its longer wavelength, which allows for decreased epidermal melanin light absorption and thus a lower risk of hyperpigmentation 21 . Besides, the longer treatment interval of some patients may also play a part.…”

“…4 The observed higher safety of PSNL is likely caused by its longer wavelength, which allows for decreased epidermal melanin light absorption and thus a lower risk of hyperpigmentation. 21 Besides, the longer treatment interval of some patients may also play a part.…”

Treatment of Nevus of Ota in Black patients with the 1064 nm QS or picosecond laser and nonablative fractional photothermolysis

“…Individual patient factors should be considered when selecting laser type and settings, including FST 6 . The majority of reports of Nevus of Ota are in Asian patients with FST I–IV.…”

“…Patients 5 and 9 had the lowest treatment response score (1%–25%). Both patients had extensive involvement of the periorbital region, which has been associated with treatment resistance 6 . Lesion color (i.e., brown vs. blue gray) has also been correlated with treatment response 6,19 .…”

Acquired dermal melanocytosis: Causing a rare but characteristic pattern of nasal alar pigmentation

“…The site has unique topography leading to practical concerns in delivering the laser beam. We believe the superficial (brownish) pigmentation may be amenable to clearance with further sessions, while the deeper (bluish) pigmentation 11 may be more refractory.…”