An association between inferior posterior staphyloma on choroidal vessels running patterns in healthy eyes

Background The effects of ocular shape changes on the retina have been studied in pathologic myopia. However, it is not well known whether there are individual differences in ocular shape in non-pathologic myopia and the influence of ocular shape on retinochoroidal disease in these eyes. Ultra-wide-field OCT (UWF-OCT), which has recently become available, has a wider imaging range and can be used to evaluate inferior posterior staphyloma (IPS). We aimed to investigate the effect of IPS on Haller vessel running patterns (HVRPs) in healthy eyes using UWF-OCT. Methods This single-center retrospective study included healthy subjects. UWF-OCT images of normal subjects were stretched vertically to enhance the macula's shape and classified into IPS and non-IPS groups with or without propensity score matching for age, sex, and ocular axis length. The HVRPs were subjectively classified into symmetry, superior dominant, and inferior dominant. Differences in the proportions of the patterns in the two groups were compared using Fisher's exact test. Results In the non-IPS group, 65 (57.5%) individuals had a symmetric pattern of Haller's vessels, 32 (28.3%) had an upper-dominant pattern, and 16 (14.1%) had a lower-dominant pattern. In the IPS group, 14 eyes (87.5%) presented an upper dominant pattern, and two (12.5%) presented a symmetric pattern. The two groups had a statistically significant difference in vascular running patterns (P < 0.001). After PSM, a similar trend was confirmed. Conclusions The eyes with IPS are likely to have superior dominant HVRPs compared to the non-IPS group in healthy eyes. Macular shape may play a role in HVRPs, which are involved in the pathogenesis of retinochoroidal diseases.