Comparison between the mean values of the CCF and LDT in all groups
| Control, group 1 (n=60) | Child class A, group 2 (n=60) | Child class B, group 3 (n=60) | Child class C, group 4 (n=60) | Significance between and within groups (p) | |
| CFF (Hz) | 45.60±1.77 | 37.93±1.34 | 34.97±2.82 | 28±1.67 | <0.001 |
| LDT (errors/min) | 1.3±1.2 | 6.5±3.5 | 4.2±3.4 | 15.9±5.7 | <0.001 |
CFF, critical flicker frequency; LDT, line drawing test.