Journal of Ophthalmology / 2014 / Article / Tab 4

Research Article

Corneal Biomechanical Changes after Crosslinking for Progressive Keratoconus with the Corneal Visualization Scheimpflug Technology

Table 4

Sample size calculation for the deflection-based parameters calculated using the new CST research software.

ParameterDelta (Mean/SD)Required sample size*

A1deflectionlength (mm)−0.08 (0.53)347
hcdeflectionlength (mm)−0.03 (0.20)350
A2deflectionlength (mm)−0.26 (0.40)21
hcdeflectionamp (mm)0.003 (0.11)10555
A1deflectionamp (mm)−0.026 (0.06)44
A2deflectionamp (mm)−0.06 (0.16)58
deflectionampmax (mm)−0.018 (0.123)368
deflectionampmax (ms)0.43 (0.98)43

Based on our data (, 3-month followup), this sample size is required to prove the differences with the -test at the significance level of 0.05 and a test power of 80%.