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Bulgarian Review of Ophthalmology

Microstructural analysis of the effects of sunlight on the anterior ocular surface

Mladena Nikolaeva Radeva


Aim: The aim of this article is to evaluate the microstructural changes of the ocular surface in response to ultraviolet (UV) exposure, and follow their dynamics using in vivo confocal microscopy during the summer season at 430 latitude. It also aims at evaluating the UV protection habits and establishing their relationship with the results.

Methods: For a period of 4 months 50 volunteers (100 eyes), aged 25 ± 4.2 years were recruited with the agreement that they will spend their summer exclusively in the region of the Black Sea coast at 430 latitude. The participants filled out special questionnaires and underwent a comprehensive eye examination before and after the summer season, and one year after the first visit. Laser scanning in vivo confocal microscopy was performed with HRT II Rostock corneal module and 5 areas of cornea, 4 in bulbar conjunctiva, and 1 in palpebral conjunctiva of the upper eyelid of both eyes were examined.

Results: The survey results showed that 84% (42 participants) considered the sun dangerous for their eyes. However, 78% (39 participants) indicated that the danger was mainly during the summer. Microstructural analysis of the cornea showed a statistically significant reduction in basal epithelial density: from 6167 ± 151 cells/mm2 to 5829 ± 168 cells/mm2. The number of keratocytes (superficial, mid and posterior stroma) as well as endothelial cell density for the follow-up period remained numerically and statistically unchanged. Conjunctival analysis revealed characteristic cystic lesions with dark centers and bright borders found in only 6 eyes (6%) before and 30 eyes (30%) after the summer season. The total area of cysts was increased 20 times and their size also increased from 12-78 μm before, to 14-174 μm after exposure to summer sun. Statistical analysis of the data showed a negative correlation between eye sun-protection habits and microstructural damage. The analysis of the data obtained during the survey one year after the initial visit revealed a tendency to return to the baseline of all encountered features, although for some of them a complete restoration was not observed.

Conclusion: Exposure to summer sun for one season, without the use of adequate sun protection, leads to clinically undetectable, microstructural changes affecting the cornea, bulbar and palpebral conjunctiva with transient, but possibly cumulative nature. The long-term effect of these changes is probably `solar ageing of the anterior ocular surface`, which appears to be similar to the well known skin damage. The results of the survey show a need to develop a preventive program and improve public awareness of UV eye injuries.


anterior ocular surface, UV damage, ultraviolet light, sun protection

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Amaro-Ortiz A, Yan B, D'Orazio JA. Ultraviolet radiation, aging and the skin: Prevention of damage by topical cAMP manipulation. Molecules. 2014;19(5):6202-19. doi: 10.3390/molecules19056202.

Godic A, Poljšak B, Adamic M, Dahmane R. The role of antioxidants in skin cancer prevention and treatment. Oxid Med Cell Longev. 2014;2014:860479. doi: 10.1155/2014/860479.

Panich U, Sittithumcharee G, Rathviboon N, Jirawatnotai S. Ultraviolet radiation-induced skin aging: The role of DNA damage and oxidative stress in epidermal stem cell damage mediated skin aging. Stem Cells Int. 2016;2016:7370642. doi: 10.1155/2016/7370642.

Ichihashi M, Ueda M, Budiyanto A, Bito T, Oka M, Fukunaga M, et al. UV-induced skin damage. Toxicology. 2003;189(1-2):21-39. doi:10.1016/S0300-483X(03)00150-1

Armstrong BK, Kricker A. The epidemiology of UV induced skin cancer. J Photochem Photobiol B. 2001;63(1-3):8-18. doi:10.1016/S1011-1344(01)00198-1

Yaar M, Gilchrest BA. Photoageing: Mechanism, prevention and therapy. Br J Dermatol. 2007;157(5):874-87. doi:10.1111/j.1365-2133.2007.08108.x

Matsumura Y, Ananthaswamy HN. Toxic effects of ultraviolet radiation on the skin. Toxicol Appl Pharmacol. 2004;195(3):298-308. doi:10.1016/j.taap.2003.08.019

Sherwin JC, McKnight CM, Hewitt AW, Griffiths LR, Coroneo MT, Mackey DA. Reliability and validity of conjunctival ultraviolet autofluorescence measurement. Br J Ophthalmol. 2012;96(6):801-5. doi: 10.1136/bjophthalmol-2011-301255.

Wolffsohn JS, Drew T, Sulley A. Conjunctival UV autofluorescence - prevalence and risk factors. Cont Lens Anterior Eye. 2014;37(6):427-30. doi: 10.1016/j.clae.2014.07.004.

Kearney S, O'Donoghue L, Pourshahidi LK, Richardson PM, Saunders KJ. The use of conjunctival ultraviolet autofluorescence (CUVAF) as a biomarker of time spent outdoors. Ophthalmic Physiol Opt. 2016;36(4):359-69. doi: 10.1111/opo.12309.

Panchapakesan J, Hourihan F, Mitchell P. Prevalence of pterygium and pinguecula: the Blue Mountains Eye Study. Aust N Z J Ophthalmol. 1998;26 Suppl 1:S2-5. doi:10.1111/j.1442-9071.1998.tb01362.x

Mimura T, Usui T, Obata H, Yamagami S, Mori M, Funatsu H, et al. Severity and determinants of pinguecula in a hospital-based population. Eye Contact Lens. 2011;37(1):31-5. doi: 10.1097/ICL.0b013e3181f91f2f.

Krutmann J, Béhar-Cohen F, Baillet G, de Ayguavives T, Ortega Garcia P, Peña-García P, et al. Towards standardization of UV eye protection: What can be learned from photodermatology? Photodermatol Photoimmunol Photomed. 2014;30(2-3):128-36. doi: 10.1111/phpp.12089.

Behar-Cohen F, Baillet G, de Ayguavives T, Garcia PO, Krutmann J, Peña-García P, et al. Ultraviolet damage to the eye revisited: Eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear. Clin Ophthalmol. 2014;8:87-104. doi: 10.2147/OPTH.S46189.

Grupcheva CN, Grupchev DI, Radeva MN, Hristova EG. UV damage of the anterior ocular surface - microstructural evidence by in vivo confocal microscopy. Cont Lens Anterior Eye. 2018. doi:10.1016/j.clae.2018.06.004.



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About The Author

Mladena Nikolaeva Radeva
Medical University of Varna

Department of Ophthalmology and Visual Sciences, Faculty of Medicine