Abstract:AIM: To investigate the affecting factors of parapapillary gamma and delta zones and other fundus morphological features in high myopia. METHODS: Seventy high myopia patients were included in this retrospective observational study and 47 patients were female. Patients were divided into three groups: no posterior staphyloma (no PS), PS with myopic traction maculopathy (PS with MTM), and PS without MTM using 3-dimensional magnetic resonance imaging and optical coherence tomography. MTM patients were further classified into three types [epiretinal membrane, macular hole, and macular retinoschisis (MRS)]. Diameters of the gamma and delta zones were measured among other morphometric variables using fundus photographs. RESULTS: Of the 70 individuals (127 eyes), the mean age was 57.46±13.56y. In univariate analysis, morphological features changed most dramatically in PS with MTM patients, who had the largest gamma zone diameters, the largest disk-fovea distance (DFD) and disk-fovea angle, and the smallest angle kappa and vertical distance of temporal arterial arcade. However, their horizontal delta zone diameter was smaller than in the patients with PS yet without MTM. In multivariate analysis, with axial length (AL) and age adjusted, the horizontal diameter in the delta zone of the PS without MTM group was still significantly larger than in the PS with MTM group (P=0.024). Comparing the three subtypes of MTM patients, the diameters of the gamma zone and DFD in MRS group were the largest. CONCLUSION: The characteristics of the gamma and delta zones change inconsistently in different stages of high myopia. These changes may be associated with anatomical changes caused by local traction. Factors such as PS, AL and age play an important role. These findings may provide a hint about the pathogenesis of traction in high myopia.
