Statistical analysis was performed using SPSS Version 17.0 (SPSS, Inc., Chicago, IL). The mean, SD, and interquartile range of the following parameters were calculated: ocular variables (IOP, spherical equivalent, AL, ACD, CCT, LOCS III score, disc area, vertical cup-to-disc ratio, and RNFL thickness); systemic variables (age, sex, systolic blood pressure, diastolic blood pressure, BMI, smoking, serum glucose, HbA1c, HDL cholesterol, LDL cholesterol, triglycerides, and creatinine); and GC-IPL thickness measured with Cirrus HD-OCT. Univariate and multiple regression analyses were performed to determine ocular and systemic factors (independent variables) association with GC-IPL thickness measurements (dependent variables). For multiple regression model, ocular and systemic parameters with P < 0.2, found in univariate linear regression analysis, were included.