The Prevalence and Determinants of Pterygium and Pinguecula in an Urban Population in Shahroud, Iran


While pterygium is considered a common eye disorder, the etiology and pathogenesis is still not known. The aim of this study was to describe the prevalence of pterygium and pinguecula in the over 40 population of Shahroud and assess associated factors. The present study is part of the phase one of the Shahroud Eye Cohort Study conducted in 2009, in which the target population was people between 40 and 64 years of age. Ophthalmic examinations were performed by two ophthalmologists who made the diagnosis of pterygium and pinguecula. We used Chi-square tests, analysis of variance, and multiple logistic regression tests to examine associations. Of the 6311 invitees, 5190 people participated in the study (response rate: 82.2%). The prevalence of pterygium in at least one eye was 9.4% (95% CI, 8.6-10.3), while 2.9% (95%CI, 2.4-3.3) had bilateral pterygium. The prevalence was significantly higher in men (11.4% vs. 8.0%), and remained relatively constant with age, while the prevalence in women significantly increased with age. The prevalence of pinguecula was 61.0% (95%CI, 59.1-62.9) in at least one eye, and 49.0% (95%CI, 47.1-50.9) in both eyes. The age difference between those with and without pinguecula was significant and the prevalence was significantly higher among men than women (70.6% vs. 53.8%). The prevalence of pterygium in our study was lower than reported rates in the world but higher than Tehran and was significantly associated with age, gender, working outdoors, and the level of education. The prevalence of unilateral and bilateral pinguecula falls in the mid range and was significantly associated with age, male gender, smoking, working outdoors, and level of education.

Buratto L, Phillips RL, Carito G, editors. Pterygium Surgery. Thorofare, NJ: Slack Inc.; 2000. p. 21-5.

Coster D. Pterygium: an ophthalmic enigma. Br J

Jaros PA, DeLuise VP. Pingueculae and pterygia. Surv Ophthalmol 1988;33(1):41-9.

Taylor HR. Aetiology of climatic droplet keratopathy and pterygium. Br J Ophthalmol 1980;64(3):154-63.

Kanski JJ. Clinical Ophthalmology: A Synopsis. 6th ed. Oxford: Butterworth-Heinemann Ltd.; 2007. p. 242-3.

Shiroma H, Higa A, Sawaguchi S, Iwase A, Tomidokoro A, Amano S, Araie M. Prevalence and risk factors of pterygium in a southwestern island of Japan: the Kumejima Study. Am J Ophthalmol 2009;148(5):766-71.

Wong TY, Foster PJ, Johnson GJ, Seah SK, Tan DT. The prevalence and risk factors for pterygium in an adult Chinese population in Singapore: the Tanjong Pagar survey. Am J Ophthalmol 2001;131(2):176-83.

Fotouhi A, Hashemi H, Khabazkhoob M, Mohammad K. Prevalence and risk factors of pterygium and pinguecula: the Tehran Eye Study. Eye (Lond) 2009;23(5):1125-9.

Cajucom-Uy H, Tong L, Wong TY, Tay WT, Saw SM. The prevalence of and risk factors for pterygium in an urban Malay population: the Singapore Malay Eye Study (SiMES). Br J Ophthalmol 2010;94(8):977-81.

West S, Munoz B. Prevalence of pterygium in Latinos: Proyecto VER. Br J Ophthalmol 2009;93(10):1287-90.

Lu P, Chen X, Kang Y, Ke L, Wei X, Zhang W. Pterygiumin Tibetans: a population-based study in China. Clin Experiment Ophthalmol 2007;35(9):828-33.

Ma K, Xu L, Jie Y, Jonas JB. Prevalence of and factors associated with pterygium in adult Chinese: the Beijing Eye Study. Cornea 2007;26(10):1184-6.

Durkin SR, Abhary S, Newland HS, Selva D, Aung T, Casson RJ. The prevalence, severity and risk factors for pterygium in central Myanmar: the Meiktila Eye Study. Br J Ophthalmol 2008;92(1):25-9.

Lu J, Wang Z, Lu P, Chen X, Zhang W, Shi K, Kang Y, Ke L, Chen R. Pterygium in an aged Mongolian population: a population-based study in China. Eye (Lond) 2009;23(2):421-7.

Tan CS, Lim TH, Koh WP, Liew GC, Hoh ST, Tan CC, Au Eong KG. Epidemiology of pterygium on a tropical island in the Riau Archipelago. Eye (Lond) 2006;20(8):908-12.

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-S5.

Norn MS. Prevalence of pinguecula in Greenland and in Copenhagen, and its relation to pterygium and spheroid degeneration. Acta Ophthalmol (Copenh) 1979;57(1):96-105.

Ashaye AO. Pterygium in Ibadan. West Afr J Med 1991;10(3-4):232-43.

Gazzard G, Saw SM, Farook M, Koh D, Widjaja D, Chia SE, Hong CY, Tan DT. Pterygium in Indonesia: prevalence, severity and risk factors. Br J Ophthalmol 2002;86(12):1341-6.

Rojas JR, Malaga H. Pterygium in Lima, Peru. Ann Ophthalmol 1986;18(4):147-9.

Wlodarczyk J, Whyte P, Cockrum P, Taylor H. Pterygium in Australia: a cost of illness study. Clin Experiment Ophthalmol 2001;29(6):370-5.

McCarty CA, Fu CL, Taylor HR. Epidemiology of pterygium in Victoria, Australia. Br J Ophthalmol 2000;84(3):289-92.

Paula JS, Thorn F, Cruz AA. Prevalence of pterygium and cataract in indigenous populations of the Brazilian Amazon rain forest. Eye (Lond) 2006;20(5):533-6.

Norn MS. Spheroid degeneration, pinguecula, and pterygium among Arabs in the Red Sea territory, Jordan. Acta Ophthalmol (Copenh) 1982;60(6):949-54.

Taylor SL, Coates ML, Vallejos Q, Feldman SR, Schulz MR, Quandt SA, Fleischer AB Jr, Arcury TA. Pterygium among Latino migrant farm workers in North Carolina.Arch Environ Occup Health 2006;61(1):27-32.

Kampitak K. The effect of pterygium on corneal astigmatism. J Med Assoc Thai 2003;86(1):16-23.

Luthra R, Nemesure BB, Wu SY, Xie SH, Leske MC. Frequency and risk factors for pterygium in the Barbados Eye Study. Arch Ophthalmol 2001;119(12):1827-32.

Verlee D. Ophthalmic survey in the Solomon Islands. Am J Ophthalmol 1968;66:304-19.

Moran DJ, Hollows FC. Pterygium and ultraviolet radiation: a positive correlation. Br J Ophthalmol 1984;68(5):343-6.

Bueno-Gimeno I, Montés-Mic R, Espaaٌ-Gregori E, Pons A. Epidemiologic study of pterygium in a Saharan population. Ann Ophthalmol 2002;34:43-6.

Nwosu SN. Ocular problems of young adults in rural Nigeria. Int Ophthalmol 1998;22(5):259-63.

Nemesure B, Wu SY, Hennis A, Leske MC. Nine-year incidence and risk factors for pterygium in the barbadoseye studies. Ophthalmology 2008;115(12):2153-8.

Saw SM, Banerjee K, Tan D. Risk factors for thedevelopment of pterygium in Singapore: a hospital-based case-control study. Acta Ophthalmol Scand 2000;78(2):216-20.

Threlfall TJ, English DR. Sun exposure and pterygium of the eye: a dose-response curve. Am J Ophthalmol1999;128(3):280-7.

Khoo J, Saw SM, Banerjee K, Chia SE, Tan D. Outdoor work and the risk of pterygia: a case-control study. Int Ophthalmol 1998;22(5):293-8.

Detels R, Dhir SP. Pterygium: a geographical study. Arch Ophthalmol 1967;78(4):485-91.

Fotouhi A, Hashemi H, Shariati M, Emamian MH, Yazdani K, Jafarzadehpur E, Koohian H, Khademi MR, Hodjatjalali, Kheirkhah A, Chaman R, Malihi S, MirzaiiM, Khabazkhoob M. Cohort Profile: Shahroud Eye Cohort Study. Int J Epidemiol 2012 Oct 17.

Tan DT, Chee SP, Dear KB, Lim AS. Effect of pterygium morphology on pterygium recurrence in a controlled trial comparing conjunctival autografting with bare sclera excision. Arch Ophthalmol 1997;115(10):1235-40.

Vojnikovic B, Njiric S, Coklo M, Toth I, Spanjol J,Marinovic M. Sunlight and incidence of pterygium on Croatian Island Rab: epidemiological study. Coll Antropol 2007;31(Suppl 1):61-2.

Saw SM, Tan D. Pterygium: prevalence, demography and risk factors. Ophthalmic Epidemiol 1999;6(3):219-28.

Mathur ML, Haldiya KR, Sachdev R, Saiyed HN. The risk of pterygium in salt workers. Int Ophthalmol 2005;26(1-2):43-7.

Bradley JC, Yang W, Bradley RH, Reid TW, Schwab IR. The science of pterygia. Br J Ophthalmol 2010;94(7):815-20.

Fotouhi A, Hashemi H, Mohammad K. Eye care utilization patterns in Tehran population: a population based crosssectional study. BMC Ophthalmol 2006;6:4.

Wu K, He M, Xu J, Li S. Pterygium in aged population in Doumen County, China. Yan Ke Xue Bao 2002;18(3):181-4.

Lindsay RG, Sullivan L. Pterygium-induced corneal astigmatism. Clin Exp Optom 2001;84(4):200-3.

Mohammad-Salih PA, Sharif AF. Analysis of pterygium size and induced corneal astigmatism. Cornea 2008;27(4):434-8.

Hochbaum DR, Moskowitz SE, Wirtschafter JD. A quantitative analysis of astigmatism induced by pterygium. J Biomech 1977;10(11/12):735-46.

Oldenburg JB, Garbus J, McDonnell JM, McDonnell PJ. Conjunctival pterygia. Mechanism of corneal topographic changes. Cornea 1990;9(3):200-4.

Lin A, Stern G. Correlation between pterygium size and induced corneal astigmatism. Cornea 1998;17(1):28-30.

Tomidokoro A, Miyata K, Sakaguchi Y, Samejima T, Tokunaga T, Oshika T. Effects of pterygium on corneal spherical power and astigmatism. Ophthalmology 2000;107(8):1568-71.

Maheshwari S. Pterygium-induced corneal refractive changes. Indian J Ophthalmol 2007;55(5):383-6.

Archila EA, Arenas MC. Etiopathology of pinguecula and pterigium. Cornea 1995;14(5):543-4.

Bell A. Pinguecula. J Vis Commun Med 2006;29(2):82-3.

IssueVol 50, No 10 (2012) QRcode
Pinguecula Population study Prevalence Pterygium Shahroud

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Rezvan F, Hashemi H, Emamian MH, Kheirkhah A, Shariati M, Khabazkhoob M, Fotouhi A. The Prevalence and Determinants of Pterygium and Pinguecula in an Urban Population in Shahroud, Iran. Acta Med Iran. 1;50(10):689-696.