The Relationship Between Corvis ST Tonometry Parameters and Ocular Response Analyzer Corneal Hysteresis

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Ocular Response Analyzer (ORA) provides corneal hysteresis (CH) based on air-jet pressure response.
• Corvis ST Tonometry (CST) offers detailed corneal structural visualization.
• Understanding the relationship between structural and dynamic corneal properties is crucial for glaucoma assessment.

Purpose of the Study:

• To investigate the association between Corvis ST Tonometry (CST) measurements and Ocular Response Analyzer (ORA) measured corneal hysteresis (CH).
• To determine if CST parameters can predict or correlate with CH values obtained from ORA.

Main Methods:

• Corneal Visualization Scheimpflug Technology (CST) and Ocular Response Analyzer (ORA) measurements were performed on 104 primary open-angle glaucoma eyes and 35 normative eyes.
• Additional measurements included axial length, corneal curvature, central corneal thickness (CCT), and Goldmann applanation tonometry.
• Linear regression analysis, guided by the bias-corrected Akaike Information Criterion, was used to assess associations between CST and ORA parameters.

Main Results:

• Several CST parameters, including deformation amplitude ratio (R=-0.51), corneal stiffness (SP A1, R=0.41), and inverse radius (R=-0.44), showed significant correlations with CH (P <0.05).
• An optimal predictive model for CH using CST parameters (applanation times, highest concavity deformation amplitude) and CCT yielded a correlation of R=0.67 (P<0.001).
• These correlations were characterized as weak to moderate, indicating distinct but related information from both devices.

Conclusions:

• Corvis ST Tonometry (CST) parameters are significantly, yet weakly to moderately, associated with Ocular Response Analyzer (ORA) measured corneal hysteresis (CH).
• CST provides valuable structural information that complements ORA's dynamic measurements for a more comprehensive corneal assessment.
• The findings highlight the potential of integrating CST data for a nuanced understanding of corneal biomechanics in glaucoma.