Purpose To compare the intraocular pressures
(IOPs) obtained with the IOPen rebound
tonometer, Goldmann applanation tonometer
(GAT) and the ocular response analyzer (ORA)
and investigate the effects of corneal
biomechanical properties on IOPen
measurements.
Methods A total of 198 normal eyes were
included in this cross-sectional and
randomized study. Three measurements were
taken using IOPen. Agreement between
tonometers was calculated using the Bland
and Altman limits of agreement (LoA)
analysis.
Results The median IOPen IOP was 3mmHg
below the GAT (Po0.001), 3mmHg below
the ORA IOP similar to Goldmann (IOPg),
and 3mmHg below the ORA IOP corrected
using corneal parameters (IOPcc)(Po0.01).
The LoA width between the IOPen and GAT
IOPs varied between 13.92 (mean IOPen IOP)
and 15.99mmHg (third IOPen measurement).
The central corneal thickness (CCT) was
unrelated to IOPen measurements (P40.05).
Corneal hysteresis (CH) and corneal rigidity
factor (CRF) were correlated with IOPen
and GAT.
Conclusions IOPen underestimated the IOP
compared with GAT and ORA. The effect of
measurement quality or measurement order on
IOPen was low. CCT did not affect the IOPen,
but the CH and CRF did. The LoA width
between the IOPen and GAT IOPs was higher
than between the ORA IOPg or ORA IOPcc
and GAT IOPs