Table 2

Quality for the population-based studies on the prevalence of pterygium

No.	First author	Publication year	Sampling scheme	Population characteristics	Prevalence definition	Diagnostic criteria	Response rate	Total score
1	Cajucom-Uy et al6	2010	Yes	Yes	Yes	Yes	0.787%	5
2	Wu et al7	2002	Yes	Yes	Yes	Yes	88.49%	5
3	Paula et al8	2006	NA	Yes	NA	Yes	NA	2
4	Viso et al9	2011	Yes	Yes	Yes	Yes	66.10%	5
5	Fotouhi et al10	2009	Yes	Yes	Yes	Yes	70.30%	5
6	Durkin et al11	2008	Yes	Yes	Yes	Yes	83.70%	5
7	Wong et al12	2001	Yes	Yes	Yes	Yes	71.80%	5
8	Lu et al13	2009	Yes	Yes	Yes	Yes	84.90%	5
9	Tan et al14	2006	Yes	Yes	Yes	Yes	86.70%	5
10	Liang et al15	2010	Yes	Yes	Yes	Yes	84%	5
11	Bueno-Gimeno et al16	2002	Yes	Yes	Yes	Yes	NA	4
12	Luthra et al17	2001	Yes	Yes	Yes	Yes	93%	5
13	McCarty et al18	2000	Yes	Yes	Yes	Yes	NA	4
14	Shiroma et al19	2009	Yes	Yes	Yes	Yes	81.20%	5
15	Ma et al20	2007	Yes	Yes	Yes	Yes	NA	4
16	West and Muñoz B21	2009	Yes	Yes	Yes	Yes	NA	4
17	Liu et al22	2001	Yes	Yes	Yes	Yes	NA	4
18	Gazzard et al23	2002	Yes	Yes	Yes	Yes	96.70%	5
19	Sherwin et al24	2013	Yes	Yes	Yes	Yes	61.50%	5
20	Lu et al2	2007	Yes	Yes	Yes	Yes	84.69%	5