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Table 1 Demographics of healthy and keratoconus subjects

From: Development of a classification system based on corneal biomechanical properties using artificial intelligence predicting keratoconus severity

  Healthy Keratoconus P value Mild KC Moderate KC Advanced KC P value* P value P value
N 116 318 N.A. 106 108 104 N.A.
Eye (right/left) 64/52 171/147 0.796 58/48 59/49 54/50 0.960
Gender (male/female) 74/42 246/72 0.004 76/30 83/25 87/17 0.007
Age (years) 29.3 ± 7.1 33.1 ± 8.1 < 0.001 33.4 ± 8.1 32.7 ± 7.0 33.2 ± 9.1 0.001 1.0 1.0
Km (D) 43.1 ± 1.3 46.9 ± 3.7 < 0.001 44.1 ± 1.7 46.7 ± 2.8 50.1 ± 3.1 0.023 < 0.001 < 0.001
ISV 21.1 ± 9.0 77.9 ± 34.8 < 0.001 40.3 ± 7.3 73.2 ± 9.5 121.0 ± 14.9 < 0.001 < 0.001 < 0.001
Normative range 27 N.A. N.A. N.A. 30–55 55–90 90–150 N.A. N.A. N.A.
KI 1.01 ± 0.02 1.21 ± 0.11 < 0.001 1.09 ± 0.03 1.19 ± 0.04 1.35 ± 0.07 < 0.001 < 0.001 < 0.001
Normative range 27 N.A. N.A. N.A. 1.07–1.15 1.10–1.25 1.15–1.45 N.A. N.A. N.A.
Rmin (mm) 7.58 ± 0.26 6.33 ± 0.68 < 0.001 7.05 ± 0.28 6.29 ± 0.36 5.63 ± 0.40 < 0.001 < 0.001 < 0.001
Normative range 27 N.A. N.A. N.A. 7.5–6.5 6.9–5.3 6.6–4.8 N.A. N.A. N.A.
Kmax (D) 44.6 ± 1.5 53.9 ± 5.9 < 0.001 48.0 ± 1.9 53.9 ± 3.1 60.2 ± 4.2 < 0.001 < 0.001 < 0.001
I-S value (D) −0.26 ± 0.7 5.7 ± 3.2 < 0.001 2.6 ± 1.2 5.4 ± 1.4 9.4 ± 2.2 < 0.001 < 0.001 < 0.001
ARC (mm) 7.8 ± 0.2 6.9 ± 0.59 < 0.001 7.4 ± 0.3 6.9 ± 0.3 6.2 ± 0.4 < 0.001 < 0.001 < 0.001
PRC (mm) 6.4 ± 0.2 5.2 ± 0.6 < 0.001 5.8 ± 0.3 5.2 ± 0.3 4.6 ± 0.4 < 0.001 < 0.001 < 0.001
TCT (μm) 560 ± 24 475 ± 44 < 0.001 505 ± 31 478 ± 34 441 ± 39 < 0.001 < 0.001 < 0.001
BAD-D 0.6 ± 0.5 7.4 ± 3.8 < 0.001 3.9 ± 1.0 6.8 ± 1.6 11.6 ± 3.1 < 0.001 < 0.001 < 0.001
bIOP (mmHg) 15.2 ± 2.2 14.3 ± 2.1 < 0.001 14.5 ± 1.7 14.4 ± 2.1 14.1 ± 2.4 0.099 1.0 1.0
CBI 0.04 ± 0.10 0.86 ± 0.30 < 0.001 0.66 ± 0.40 0.93 ± 0.20 0.99 ± 0.00 < 0.001 < 0.001 0.224
TBI 0.08 ± 0.13 0.99 ± 0.04 < 0.001 0.99 ± 0.07 0.99 ± 0.00 0.99 ± 0.00 < 0.001 1.0 1.0
  1. * Between Healthy and mild KC; Between mild KC and moderate KC; Between moderate KC and advanced KC. ARC anterior radius of curvature; BAD-D Belin/Ambrósio total deviation value; CBI Corvis biomechanical index; bIOP biomechanical intraocular pressure by Corvis ST; I-S inferior-superior; ISV index of surface variance; KI keratoconus index; Km mean keratometry values; Kmax maximal keratometry value; N number of subjects; N.A. not applicable; PRC posterior radius of curvature; Rmin minimum radius; TBI tomographic and biomechanical index; TCT thinnest corneal thickness. Normative range of ISV, KI and Rmin based on Pentacam Software also published in [27]. Bold type signifies P < 0.05