Comparing Corneal Pachymetry Readings from Pachmate and Optovue OCT

Background: This study compared optical to ultrasound corneal pachymetry for
measuring the central corneal thickness of a human eye. Corneal pachymetry is the
process of measuring the thickness of the cornea. Ultrasound corneal pachymetry has
been considered the "gold standard" for measuring corneal thickness for many years. This study compared a Pachmate® ultrasound pachymeter to an Optovue® iVue optical
coherence tomography (OCT).
Methods: This research looked at the data from 136 healthy corneas of patients
from Mason Family EyeCare. The data was collected using the Optovue® iVue OCT
then Pachmate®. Performing it in this order ensured there that there was no alternation of
the cornea from applanation of the ultrasound probe. The information from the Optovue
iVue® OCT was compared to that of the Pachmate® to see if it was a viable alternative
option to take corneal thickness readings.
Results: Corneal thickness readings from the Optovue® iVue OCT ranged from
445 to 618 μm with an average of 525.63 μm and the reading from the Pachmate®
ultrasound pachymeter ranged from 469 to 658 μm with an average of 555.44 μm. The
difference (Pachmate® minus Optovue® iVue) between each individual reading from the
two methods ranged from -1 to 65 μm with an average 29.80 μm.
Conclusion: The data collected and analyzed shows that there is a statically
significant difference between the two different pachymetry methods with a p=0.000.
These results suggest the Optovue® iVue OCT underestimates the pachymetry reading as compared to the Pachmate®