{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T16:17:59Z","timestamp":1776269879627,"version":"3.50.1"},"reference-count":15,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T00:00:00Z","timestamp":1776211200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Treating atrophic acne scars in Asian skin (Fitzpatrick types III\u2013V) is challenging due to the elevated risk of post-inflammatory hyperpigmentation (PIH). While picosecond lasers with fractional handpiece treatment are effective, the optimal balance between fluence, passes, clinical outcome, and downtime remains controversial.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case presentation<\/jats:title>\n                    <jats:p>\n                      A 28-years-old Asian male with moderate atrophic acne scars was treated with a 532-nm picosecond Nd:YAG laser using a fractional handpiece. An ultra-low fluence of 0.03 J\/cm\n                      <jats:sup>2<\/jats:sup>\n                      was applied (8-mm spot size, 4 passes, 2,511 total pulses).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Clinical follow-up demonstrated observable changes in scar contour and skin surface irregularity after a single treatment session, without downtime or PIH. Optical Coherence Tomography (OCT) revealed intraepidermal vacuole-like structures exclusively at the ultra-low setting (0.03 J\/cm\n                      <jats:sup>2<\/jats:sup>\n                      ), while higher fluences (0.05\u20130.2 J\/cm\n                      <jats:sup>2<\/jats:sup>\n                      ) failed to generate similar discrete OCT findings.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Ultra-low fluence, high-pulse-count 532-nm treatment may be associated with OCT-detectable intraepidermal vacuole-like response not observed at higher fluences. While the biological mechanism remains to be elucidated, these findings highlight the possibility of a non-linear dose\u2013response phenomenon and support further investigation into sub-threshold treatment paradigms in pigment-prone populations.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmed.2026.1793087","type":"journal-article","created":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T15:18:06Z","timestamp":1776266286000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Ultra-low fluence 532 nm picosecond laser treatment for acne scars: OCT-observed epidermal vacuole-like changes\u2013a case report"],"prefix":"10.3389","volume":"13","author":[{"given":"Patricia Yu-Chun","family":"Peng","sequence":"first","affiliation":[{"name":"Kaohsiung Medical University Hospital","place":["Kaohsiung, Taiwan"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hung-Chia","family":"Chang","sequence":"additional","affiliation":[{"name":"P-Skin Professional Clinic","place":["Kaohsiung, Taiwan"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hsien-Li Peter","family":"Peng","sequence":"additional","affiliation":[{"name":"P-Skin Professional Clinic","place":["Kaohsiung, Taiwan"]},{"name":"Department of Dermatology, Tri-Service General Hospital, National Defense Medical University","place":["Taipei, Taiwan"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,15]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"646","DOI":"10.1002\/lsm.22540","article-title":"The histology of skin treated with a picosecond alexandrite laser and a fractional lens array.","volume":"48","author":"Tanghetti","year":"2016","journal-title":"Lasers Surg 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