In Vivo Biomechanical Changes Associated With Keratoconus Progression

Figures & data

Figure 1. Distribution of the corneal biomechanical parameters at the first and last examinations. A: SSI: stress-strain index. B: Integrated Inv Radius: integrated inverse radius. C: SP-A1: stiffness parameter at the first applanation. D: Deflection Ampl: deflection amplitude. E: DA Ratio: deflection amplitude ratio. F: bIOP: biomechanically corrected intraocular pressure.

Table 1. Clinical characteristics.

	First exam				Second exam				Second - first exam
	mean	SD	min	max	mean	SD	min	max	mean	SD	min	max	p-value
ARC (mm)	6.86	0.45	5.96	7.72	6.46	0.47	5.45	7.53	−0.40	0.28	−1.14	−0.11	<0.001
PRC (mm)	5.25	0.46	4.28	6.54	4.86	0.46	3.91	6.2	−0.39	0.24	−0.98	−0.12	<0.001
Pachy Min (µm)	466.7	28.5	414	520	441.7	33.3	344	497	−25.0	17.5	−85	−7	<0.001
K Max (D)	54.41	4.34	44.5	64.4	57.09	4.99	46	65.9	2.68	2.32	−0.5	10.5	<0.001
Ele F Thinnest (µm)	20.66	8.2	7	42	25.69	8.26	10	39	5.03	4.16	−3	16	<0.001
Ele B Thinnest (µm)	45.12	17.87	8	96	54.09	17.15	19	90	8.97	9.09	−19	32	<0.001
SSI	0.82	0.14	0.54	1.17	0.75	0.12	0.49	0.99	−0.10	0.06	−0.21	0	<0.001
IIR (1/mm)	10.21	1.86	6.52	16.56	11.17	1.85	6.85	16.13	0.95	1.04	−2.34	2.69	<0.001
SP-A1 (mmHg/mm)	67.0	18.2	36.0	107.0	60.9	17.8	27.0	94.6	−6.1	12.0	−31.8	18.9	0.011
DA (mm)	1.1	0.11	0.89	1.35	1.14	0.13	0.97	1.45	0.04	0.13	−0.22	0.53	0.056
DA Ratio	5.54	0.78	4.07	7.83	5.77	0.93	4.10	8.01	0.23	0.58	−1.31	1.49	0.034
bIOP (mmHg)	15.62	1.41	10.6	18.3	15.56	1.24	12.9	18.6	−0.05	1.21	−2.0	2.3	0.731

ARC: anterior radius of curvature; PRC: posterior radius of curvature; Pachy Min: minimum corneal thickness; K Max: maximum anterior axial corneal curvature; Ele F Thinnest: anterior corneal elevation at the thinnest point; Ele B Thinnest: posterior corneal elevation at the thinnest point; SSI: stress-strain index; IIR: integrated inverse radius; SP-A1: stiffness parameter at the first applanation; DA: deflection amplitude; bIOP: biomechanically corrected intraocular pressure.

Data availability statement

The data that support the findings of this study are available from the corresponding author, BL, upon reasonable request.