Statistical analysis
VF
Patient and eye characteristics were reported as mean (95% CI) for continuous data and count (percentage) for categorical data. MD, PSD, foveal threshold (FT), and VFI were compared using mixed-effects model between the two perimeters. Reliability indices were illustrated in a kernel density estimate plot to compare the values from two perimeters. Kernel density estimate is a non-parametric way to estimate the probability density function of a random variable. In other words, it provides a smoothed version of a histogram, giving a continuous curve. The Bland-Altmann plot assessed the LoA between the two perimeters. Measurement time for performing VF for both eyes was recorded for each device. It only accounted for the actual examination time and excluded the setup time needed for testing the second eye with HFA. All statistical analyses were performed with Stata software (version 15; StataCorp, College Station, Texas). Statistical significance for tests was set at P ≤ 0.05.