Prevalence rates vary from <1% to 30% or more, depending on geographic location of the study population, with higher rates occurring in areas with high ultraviolet (UV) light intensity.[1]Saw SM, Tan D. Pterygium: prevalence, demography and risk factors. Ophthalmic Epidemiol. 1999 Sep;6(3):219-28.
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[2]Mackenzie FD, Hirst LW, Battistutta D, et al. Risk analysis in the development of pterygia. Ophthalmology. 1992 Jul;99(7):1056-61.
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[3]Rezvan F, Khabazkhoob M, Hooshmand E, et al. Prevalence and risk factors of pterygium: a systematic review and meta-analysis. Surv Ophthalmol. 2018 Sep-Oct;63(5):719-35.
http://www.ncbi.nlm.nih.gov/pubmed/29551597?tool=bestpractice.com
[4]Liu L, Wu J, Geng J, et al. Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis. BMJ Open. 2013 Nov 19;3(11):e003787.
https://bmjopen.bmj.com/content/3/11/e003787
http://www.ncbi.nlm.nih.gov/pubmed/24253031?tool=bestpractice.com
The overall global prevalence of pterygium is around 12%.[3]Rezvan F, Khabazkhoob M, Hooshmand E, et al. Prevalence and risk factors of pterygium: a systematic review and meta-analysis. Surv Ophthalmol. 2018 Sep-Oct;63(5):719-35.
http://www.ncbi.nlm.nih.gov/pubmed/29551597?tool=bestpractice.com
Prevalence increases with age.[3]Rezvan F, Khabazkhoob M, Hooshmand E, et al. Prevalence and risk factors of pterygium: a systematic review and meta-analysis. Surv Ophthalmol. 2018 Sep-Oct;63(5):719-35.
http://www.ncbi.nlm.nih.gov/pubmed/29551597?tool=bestpractice.com
[4]Liu L, Wu J, Geng J, et al. Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis. BMJ Open. 2013 Nov 19;3(11):e003787.
https://bmjopen.bmj.com/content/3/11/e003787
http://www.ncbi.nlm.nih.gov/pubmed/24253031?tool=bestpractice.com
[5]Bikbov MM, Zainullin RM, Kazakbaeva GM, et al. Pterygium prevalence and its associations in a Russian population: the ural eye and medical study. Am J Ophthalmol. 2019 Sep;205:27-34.
http://www.ncbi.nlm.nih.gov/pubmed/30849347?tool=bestpractice.com
Some studies report equal occurrence in men and women, while others report a slight predominance in men.[3]Rezvan F, Khabazkhoob M, Hooshmand E, et al. Prevalence and risk factors of pterygium: a systematic review and meta-analysis. Surv Ophthalmol. 2018 Sep-Oct;63(5):719-35.
http://www.ncbi.nlm.nih.gov/pubmed/29551597?tool=bestpractice.com
[4]Liu L, Wu J, Geng J, et al. Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis. BMJ Open. 2013 Nov 19;3(11):e003787.
https://bmjopen.bmj.com/content/3/11/e003787
http://www.ncbi.nlm.nih.gov/pubmed/24253031?tool=bestpractice.com
[5]Bikbov MM, Zainullin RM, Kazakbaeva GM, et al. Pterygium prevalence and its associations in a Russian population: the ural eye and medical study. Am J Ophthalmol. 2019 Sep;205:27-34.
http://www.ncbi.nlm.nih.gov/pubmed/30849347?tool=bestpractice.com
It is possible these different results are due to populations where there are sex differences in lifestyle/outdoor work, and therefore exposure to UV light, rather than sex itself being a risk factor for pterygium.[4]Liu L, Wu J, Geng J, et al. Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis. BMJ Open. 2013 Nov 19;3(11):e003787.
https://bmjopen.bmj.com/content/3/11/e003787
http://www.ncbi.nlm.nih.gov/pubmed/24253031?tool=bestpractice.com