The (a) average heart rate, (b) SDNN and (c) rMSSD in the TD, “w/med” ASD and “w/o med” ASD groups obtained in the five HRV measurement phases. The HRV measurement phases are numbered as 1: before PLR test, 2: during LA PLR, 3: during dark adaptation, 4: during DA PLR, and 5: after PLR test. The error bars indicate the standard error.