Pterygium Is Related to Short Axial Length

PURPOSE: To test the hypothesis that pterygium presents with both refractive and anatomical changes, especially short axial length. METHODS: A retrospective, hospital-based cross-sectional study included 521 eyes from 521 patients who were enrolled through a community survey by Shanghai Heping Eye Hospital was conducted. Patients with primary pterygium in at least 1 eye were considered the pterygium group, and those with normal eyes were considered the nonpterygium group. The prevalence and length of pterygium, refractive characteristics including spherical power, astigmatism, corneal curvature, and anatomical parameters including axial length, anterior chamber depth, endothelial cell density, and corneal thickness were compared between groups. RESULTS: Five hundred twenty-one eyes of 521 patients (214 men and 307 women) with a mean age of 70.5 ± 7.6 years were included in the study. The prevalence of hyperopia (81.6%, 65.1%, P = 0.001), axial length (23.1 ± 1.2 mm, 24.2 ± 2.4 mm, P < 0.001), anterior chamber depth (2.9 ± 0.3 cm, 3.1 ± 0.4 cm, P = 0.001), flat K value (42.94 ± 2.16 diopters, 43.73 ± 1.48 diopters, P = 0.002), Kmax (51.13 ± 7.74 diopters, 47.49 ± 5.62 diopters, P < 0.001), and spherical power (0.97 ± 2.40 diopters, −0.82 ± 4.40 diopters, P < 0.001) were statistically different between the pterygium and nonpterygium groups. Age (r = −0.21, P = 0.025), corneal astigmatism (r = −0.41, P < 0.001), flat K value (r = −0.39, P < 0.001), and endothelial cell density (r = −0.33, P = 0.001) were all negatively correlated with the length of pterygium. The prevalence of pterygium and severe pterygium over 3 mm were statistically different according to the severity of hyperopia (P < 0.001) and axial length (P < 0.001). Stratified χ(2) analysis showed that axial length, rather than hyperopia, was a related factor to pterygium (odds ratio = 5.23, 95% confidence interval: 2.50–10.93). CONCLUSIONS: We conclude from our study that the prevalence of pterygium is related to small eye size. SDF-1/CXCR4 signaling may play a vital role in pterygium and shorter axial length. Further study focused on SDF-1/CXCR4 signaling will be needed.