Pterygium is a common ocular disease that can cause visual impairment. The aim of this study was to investigate the type of astigmatism and its related factors in pterygium patients referred to the Eye Clinic Medical center of Valiasr Hospital has been conducted from February 2018 to April.

In this descriptive-analytic study, which was done by simple non-probabilistic sampling, all patients referred to the clinic of Vali-e-Asr Hospital in Birjand who had a pterygium were studied from the point of astigmatism as with-the-rule, against the rule and oblique.

The results of this study showed that out of 187 cases of pterygium, 95 (50.8%) were female and 92 (49.2%) were male. The mean age of the patients participating in the study was 55.09 ± 15.69 (at least 20 and at most 90 Year (78.7%) Oblique astigmatism, 64 cases (34.2%) With the rule and 45 cases (24.1%) Against the rule was created by the pterygium. In the healthy group, these values were 38 %, 45.4%, 16.7%. There was no significant correlation between the types of astigmatism in the two groups (p = 0.12). Also, the severity of astigmatism (diopter of the eye) in all three types was significantly different in healthy and pterygium groups The mean of astigmatism in pterygium size was 4.7 ± 2.19 and in the size The mean of the severity of astigmatism was significantly different in terms of pterygium size (p <0.001).

The results of this study showed that the most common type of astigmatism was created by pterygium was Oblique, which did not differ significantly from that of the with the rule. The comparison of the mean of astigmatism severity in terms of pterygium size showed a statistically significant difference and the median severity in pterygium size> 4 mm was more than other cases