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Table 2 Comparative analysis of age, refractive, aberrometric, pachymetric and morpho-volumetric data among the non-Down syndrome (DS) keratoconus (KC) group, DS with non-KC topography and DS with KC topography groups

From: A three-dimensional morpho-volumetric similarity study of Down syndrome keratopathy vs. keratoconus

Variables (mean ± SD)

Non–DS KC group (n = 99)

DS non–KC topography (n = 27)

DS KC topography total (n = 16)

Comparison of three groups P*

Statistically significant pairwise comparisons P**

Age (years)

27.1 ± 6.9

22.3 ± 10.1

27.6 ± 12.7

0.034

(0.039)a

Spherical equivalent (diopters)

− 1.99 ± 3.05

− 0.18 ± 4.56

− 1.65 ± 4.44

< 0.0001

(< 0.0001)a

HOA RMS (µm)

1.44 ± 0.79

1.02 ± 0.89

1.55 ± 1.35

0.003

(0.002)a

Central corneal thickness (µm)

500.6 ± 31.2

505.3 ± 23.7

479.0 ± 34.1

0.059

P > 0.05

Dapexant (mm)

0.003 ± 0.006

0.004 ± 0.008

0.011 ± 0.011

< 0.0001

(0.022)a,

(< 0.0001)b

Dapexpost (mm)

0.161 ± 0.074

0.061 ± 0.033

0.100 ± 0.060

< 0.0001

(< 0.0001)a,

(0.003)b

Dmctant (mm)

1.045 ± 0.322

1.467 ± 1.036

1.428 ± 1.086

0.620

P > 0.05

Dmctpost (mm)

0.975 ± 0.305

1.384 ± 1.021

1.341 ± 1.037

0.646

P > 0.05

Aant (mm2)

43.19 ± 0.18

43.43 ± 0.22

43.50 ± 0.31

< 0.0001

(< 0.0001 both)a,b

Apost (mm2)

44.39 ± 0.30

44.60 ± 0.38

44.59 ± 0.51

0.054

P > 0.05

Atot (mm2)

103.22 ± 1.18

103.64 ± 1.40

102.80 ± 1.60

0.301

P > 0.05

Aapexant (mm2)

1.64 ± 1.98

4.06 ± 0.25

3.83 ± 0.32

< 0.0001

(< 0.0001)a,

(0.009)b

Aapexpost (mm2)

3.99 ± 0.26

4.05 ± 0.24

3.83 ± 0.27

0.035

(0.029)c

Amctpost (mm2)

3.98 ± 0.26

4.02 ± 0.24

3.80 ± 0.29

0.016

(0.013)c

Cx (mm)

0.0160 ± 0.0430

− 0.0009 ± 0.0390

− 0.009 ± 0.061

0.014

(0.035)b

Cy (mm)

0.026 ± 0.035

0.034 ± 0.022

− 0.002 ± 0.055

0.027

(0.044)b,

(0.031)c

Cz (mm)

0.763 ± 0.027

0.788 ± 0.025

0.777 ± 0.035

0.001

(0.001)b

Vtotal

23.95 ± 1.53

24.12 ± 1.62

22.73 ± 1.85

0.015

(0.027)b,

(0.017)c

  1. Aant, Apost = area of the anterior and posterior corneal surfaces; Atot = sum of anterior, posterior and perimetric corneal surface areas; Aapexant, Aapexpost = sagittal plane apex area of the cornea within the sagittal plane passing through the Z axis and the highest point (apex) of the anterior and posterior corneal surfaces; Amctppost = sagittal plane area of the cornea within the sagittal plane passing through the Z axis and the minimum thickness points in the posterior corneal surfaces; Cx, Cy, Cz = center of mass coordinates (X, Y, Z) of the solid; Dapexant, Dapexpost = average distance from the Z axis to the highest point (apex) of the anterior and posterior corneal surfaces; Dmctant, Dmctpost = average distance in the XY plane from the Z axis to the minimum thickness points of the anterior and posterior corneal surfaces; DS = Down syndrome; HOA = high-order aberrations;  KC = keratoconus; RMS = root mean square; SD = standard deviation
  2. P < 0.05 and bold values indicate statistical significance
  3. *Comparison of the non-DS KC group, DS with non-KC topography and DS with KC topography subgroups (independent samples Kruskal-Wallis test, P < 0.05 indicates statistically significant difference)
  4. **Pairwise comparisons among the three groups (independent samples Kruskal-Wallis test, adjusted P < 0.05 indicates statistically significant difference after post-hoc corrections)
  5. aStatistically significant difference between the non-DS KC group and DS with non-KC topography group
  6. bStatistically significant difference between the Non-DS KC group and Down syndrome with KC topography group
  7. cStatistically significant difference between the DS with non-KC topography and DS with KC topography group
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Eye and Vision

ISSN: 2326-0254