Table 1 Demographics for patients with normal eyes, mild, and moderate keratoconus (KC)

N

43

16

41

Age (years) (mean ± SD) (min–max)

29.2 ± 7.5 (18.0–45.0)

35.6 ± 6.7 (23.0–45.0)

30.9 ± 7.4 (18.0–43.0)

0.014*

Gender (m/f) (%)

27 (63%)/16 (37%)

10 (63%)/6 (37%)

37 (90%)/4 (10%)

0.009**

Eyes (r/l) (%)

22 (51%)/21 (49%)

9 (56%)/7 (44%)

15 (37%)/26 (63%)

0.272**

Kmax (D) (mean ± SD) (min–max)

43.7 ± 1.5 (40.7–46.6)

51.5 ± 3.3 (48.1–59.7)

59.7 ± 6.8 (47.3–73.5)

< 0.001*

I-S value (D) (mean ± SD) (min–max)

 − 0.01 ± 0.66  (− 1.80–1.00)

5.46 ± 1.74 (2.80–8.58)

8.66 ± 2.87 (3.23–13.92)

< 0.001*

KISA (mean ± SD) (min–max)

6.2 ± 5.9 (0.3–27.2)

440.6 ± 331.9 (101.0–1449.0)

4369.7 ± 5392.3 (104.0–25,295.0)

< 0.001*

BAD-D (mean ± SD) (min–max)

0.57 ± 0.59 ( − 0.96–1.52)

5.59 ± 0.82 (4.09–6.78)

11.23 ± 3.22 (7.14–19.86)

< 0.001*