(n=21, 100%) (n=13, 61.9%) (n=11, 52.3%) (n=6, 28.5%) (n=51, 100%)
Clear 0 16 (76.1%)** 11 (84.6%)** 7 (63.6%)** 5 (83.3%)** 39 (76.4%)**
Mild 1 4 (19%)* 2 (15.3%)* 3 (27..2%)** 0** 9 (17.6%)**
Moderate 2 1 (4.7%)** 0** 0** 1 (16.6%)** 2 (3.9%)**
Severe 3 0** 0** 1 (9%)* 0 1 (1.9%)**
*P<0.05: statistically significant, p<0.001: statistically highly significant