PurposeThe purpose of this study was to investigate the uncertainty in the formula
predicted refractive outcome REFU after cataract surgery resulting from measurement
uncertainties in modern optical biometers using literature data for within-subject
standard deviation S-w. MethodsThis Monte-Carlo simulation study used a large dataset
containing 16 667 preoperative IOLMaster 700 biometric measurements. Based on literature
S-w values, REFU was derived for both the Haigis and Castrop formulae using error
propagation strategies. Using the Hoya Vivinex lens (IOL) as an example, REFU was
calculated both with (WLT) and without (WoLT) consideration of IOL power labelling
tolerances. ResultsWoLT the median REFU was 0.10/0.12 dpt for the Haigis/Castrop formula,
and WLT it was 0.13/0.15 dpt. WoLT REFU increased systematically for short eyes (or
high power IOLs), and WLT this effect was even more pronounced because of increased
labelling tolerances. WoLT the uncertainty in the measurement of the corneal front
surface radius showed the largest contribution to REFU, especially in long eyes (and
low power IOLs). WLT the IOL power uncertainty dominated in short eyes (or high power
IOLs) and the uncertainty of the corneal front surface in long eyes (or low power
IOLs). ConclusionsCompared with published data on the formula prediction error of
refractive outcome after cataract surgery, the uncertainty of biometric measures seems
to contribute with 1/3 to 1/2 to the entire standard deviation. REFU systematically
increases with IOL power and decreases with axial length.
