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Investigating the Effects of UVC Exposure at the Limbus
Bethany P Torr1,2, Jennifer P Craig1, Simon J Dean1
1Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Cells
|June 11, 2026
Summary
Ultraviolet C (UVC) light causes DNA damage primarily in superficial corneal layers, sparing deeper tissues. This study found no damage to limbal stem cells even with prolonged, high-dose UVC exposure in porcine and human corneas.
Area of Science:
- Ophthalmology
- Photobiology
- Molecular Biology
Background:
- Preclinical studies suggest low-intensity ultraviolet C (UVC) light is safe and effective for bacterial keratitis in mice.
- The impact of UVC on limbal tissues, crucial for corneal health, remains under-investigated.
Purpose of the Study:
- To evaluate the depth and density of UVC-induced DNA damage in porcine and human limbal tissues.
- To assess the safety of supratherapeutic UVC doses on limbal stem cells.
Main Methods:
- Porcine and human corneas were exposed to supratherapeutic doses of UVC light (265 nm).
- Exposure durations varied from 1 to 60 minutes.
- Immunohistochemistry detected cyclobutane pyrimidine dimers (CPDs) as markers of DNA damage.
Main Results:
- UVC-induced DNA damage (CPDs) was confined to superficial corneal epithelial layers in both species.
- No significant difference in CPD formation was observed with increasing UVC exposure time.
- Damage depth averaged 13.3 ± 8.43 µm within the corneal epithelium.
Conclusions:
- UVC-induced DNA damage is superficial and does not penetrate deeper corneal tissues.
- Limbal stem cells are protected from UVC-induced DNA damage, even at high doses and extended exposure times.
- UVC light shows potential for therapeutic use without compromising limbal stem cell integrity.
