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. 2020 Mar 4;10(1):45–53. doi: 10.4103/tjo.tjo_15_19

Table 1.

Describes the corneal biomechanical parameters, its abbreviation and brief description

Parameters Abbreviation Description
Biomechanically corrected intraocular pressure bIOP Derived by finite element simulations that take into account the influence of central corneal thickness, age, and DCR parameters
First applanation A1 A1 Moment at the first applanation of the cornea during the air puff
A1 time (ms) A1T Time from start to A1
A1 velocity (m/s) A1V Velocity of corneal apex at A1
A1 deformation amplitude A1DA Moving distance of the corneal apex from the initial position to that at the A1 Time
A1 deflection length A1DL Length of the flattened cornea at A1
A1 deflection amplitude A1DeflA Similar to A1DA without whole eye movement
A1 delta arc length A1dArclength Change in Arclength from initial state to A1, in a defined 7-mm zone
Second applanation A2 A2 Moment at the first applanation of the cornea during the air puff
A2 time (ms) A2T Time from start to A2
A2 velocity (m/s) A2V Velocity of corneal apex at A2
A2 deformation amplitude A2DA Moving distance of the corneal apex from the initial position to that at A2 time
A2 deflection length A2DL Length of the flattened cornea at A2
A2 deflection amplitude A2DeflA Similar to A2DA without whole eye movement
A2 delta arc length A2dArclength Change in arclength from initial state to A2, in a defined 7-mm zone
Highest concavity HC Moment that the cornea assumes its maximum concavity during the air puff
HC time HCT Time to reach the maximum deformation
Radius (mm) Rad Central curvature radius at the highest concavity
HC deformation amplitude HCDA Distance of the corneal apex movement from the initiation of the deformation to the highest concavity
HC deflection length HCDL Length of the flattened cornea at highest concavity
HC deflection amplitude HCDeflA Similar to HCDA without whole eye movement
Peak distance PD Distance between the two surrounding peaks of the cornea at the highest concavity
HC delta Arc length HC dArclength Change in arclength during the highest concavity moment from the initial state, in a defined 7-mm zone
Maximum Max Similar as HC
Max deformation amplitude Max DA Distance of the corneal apex movement from the initiation of the deformation to the highest concavity
Max deflection amplitude Max DeflA Similar to HCDeflA
Max delta arc length Max dArclength Change in arclength during the highest concavity moment from the initial state, in a defined 7-mm zone
Vinciguerra screening parameters
Deformation amplitude ratio max (2 mm) DA ratio max Ratio between the deformation amplitude at the apex and the average deformation amplitude measured at 2 mm from the center
Ambrósio’s relational thickness to the horizontal profile ARTh Describes thickness profile in the temporal-nasal direction and defined as corneal thickness thinnest to pachymetric progression
Integrated radius INR Area under the inverse concave radius versus time curve
Stiffness parameter at A1 SP A1 Describes corneal stiffness as defined by resultant pressure (Pr) divided by deflection amplitude at A1
Corvis biomechanical index CBI Overall biomechanical index for keratoconus detection

HC: Highest concavity, DCR: Dynamic corneal response

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