{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T11:21:13Z","timestamp":1785410473850,"version":"3.56.0"},"reference-count":35,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,5,23]],"date-time":"2026-05-23T00:00:00Z","timestamp":1779494400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Photon Therapeutics Limited","award":["6000947"],"award-info":[{"award-number":["6000947"]}]},{"name":"Ocular Surface Laboratory at the University of Auckland"},{"id":[{"id":"https:\/\/ror.org\/03b94tp07","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Purpose: Preclinical studies report low-intensity ultraviolet C (UVC) light to be safe and effective in treating murine bacterial keratitis, however, limbal impacts of UVC have yet to be investigated directly. This study evaluated the depth and density of UVC-induced DNA damage in the porcine and human limbus following UVC exposures of varying supratherapeutic dose. Methods: The corneoscleral junction (limbus) of full-thickness porcine corneas was exposed to supratherapeutic doses of UVC light (265 nm, 1.93 mW\/cm2) for 5, 10, 15, 30, or 60 min (exposure groups) or remained unexposed for the same durations (control groups), with a sample size of 6 per group. In parallel, human corneal tissue was exposed to UVC for 1 or 5 min and processed identically. Following exposure, all tissues were frozen, dissected, and analysed using immunohistochemistry to detect cyclobutane pyrimidine dimers (CPDs) as markers of DNA damage. CPD distribution, depth, and density were subsequently evaluated. Results: CPDs were localised predominantly in the superficial corneal epithelial layers, irrespective of the UVC dose. The mean \u00b1 SD thickness of the corneal epithelium in the UVC-exposed groups was 38.9 \u00b1 18.9 \u00b5m, and the average depth of CPD formation was 13.3 \u00b1 8.43 \u00b5m. The proportions of cells affected by CPDs within the corneal epithelium (mean \u00b1 SD) were 47.8 \u00b1 25.6%, 58.5 \u00b1 16.2%, 39.9 \u00b1 26.4%, 41.3 \u00b1 27.3%, and 38.9 \u00b1 28.3% for exposure durations of 5, 10, 15, 30, and 60 min, respectively (p &gt; 0.05). Human cornea showed similarly limited penetration, with no difference in CPD proportions between the 1 and 5 min UVC exposures (p = 0.70). Conclusions: UVC-induced DNA damage in both species was confined to the superficial cellular layers of the cornea, with no detectable damage observed in deeper tissues, including those where limbal stem cells reside, even after supratherapeutic doses of up to one hour of exposure.<\/jats:p>","DOI":"10.3390\/cells15110967","type":"journal-article","created":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T10:19:52Z","timestamp":1779877192000},"page":"967","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Investigating the Effects of UVC Exposure at the Limbus"],"prefix":"10.3390","volume":"15","author":[{"given":"Bethany P.","family":"Torr","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand"},{"name":"Department of Optometry and Vision Science, Aotearoa New Zealand National Eye Centre, The University of Auckland, Auckland 1142, New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8297-5319","authenticated-orcid":false,"given":"Jennifer P.","family":"Craig","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4594-123X","authenticated-orcid":false,"given":"Simon J.","family":"Dean","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9090-1034","authenticated-orcid":false,"given":"Trevor","family":"Sherwin","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8282-9637","authenticated-orcid":false,"given":"Sanjay","family":"Marasini","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1016\/j.jtos.2022.05.004","article-title":"Preclinical confirmation of UVC efficacy in treating infectious keratitis","volume":"25","author":"Marasini","year":"2022","journal-title":"Ocul. 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