Corneal biomechanical properties and their association with

Corneal biomechanical properties and their
association with intraocular pressure (IOP)
and central corneal thickness (CCT)
Dimitrios P. Bessinis1, Pandelis A. Papadopoulos,2,3, Alexandros A. Papadopoulos2, Konstantinos
Kakoulidis3 and Andrej Cernak3
1. Department of Ophthalmology, Evaggelismos General Hospital,
Athens, Greece
2. Ophthalmo-Check Eye Center, Athens, Greece
3. Department of Ophthalmology, Slovak Medical University,
Bratislava, Slovakia
the authors declare that they have no financial interest in the products mentioned in the study
We hypothesized and investigated the association of intraocular pressure (IOP) and central
corneal thickness (CCT) with the biomechanical properties of the cornea, including the
applanation lengths, the peak distance and the peak radius of the highest concavity as well as
the deformation amplitude. Assesment of biomechanical properties as well as IOP and CCT was
made with Corvis ST. Corvis ST is a Non-Contact Tonometer which allows the measurement of
IOP and CCT with a high speed Scheimpflug camera (4300 fps) and records the movement
reaction to the cornea to an air impulse.
Fifty five eyes of 28 patients were examined with Corvis ST for IOP, CCT and biomechanical
properties. Statistical analysis was performed with SPSS software for Windows using Spearman’s
The Oculus Corvis ST
Datasheet of Corvis ST
Still image from the Scheimpflug camera
Higher IOP was associated with higher applanation length 2, lower peak
distance, higher peak radius and lower deformation amplitude
Higher CCT was associated with higher applanation length 2, lower
peak distance, higher peak radius and lower deformation amplitude
In our investigation a correlation was detected between IOP, CCT and corneal biomechanical
properties. It appears that a higher IOP and a thicker cornea results in bigger concavity and rebound
of cornea to normal state. On the contrary the peak distance of the highest concavity and the
deformation amplitude is lower when IOP and CCT are high. It seems that even though there is an
association of IOP and CCT it may not be in the way previously believed. Neither IOP nor CCT
interact with applanation length 1, which is the highest deformation length of the cornea immediately
after the air impulse. Based on our results we suggest that applanation length 1 may be a key to
understanding corneal biomechanics as it is independent of other factors such as IOP and CCT.
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