Biomechanical parameters of the cornea measured with the Ocular Response Analyzer in normal eyes.
BACKGROUND
To evaluate the relationships between Reichert Ocular Response Analyzer (ORA) parameters corneal hysteresis (CH) and corneal response factor (CRF) and ocular dimensions, age and intraocular pressure.


METHODS
Two hundred and twelve eyes of 212 participants with no ocular pathology had CH and CRF measured with the ORA. Intraocular pressure (IOP) was measured with the Dynamic Contour tonometer and central corneal thickness (CCT) was also evaluated. Partial least squares linear regression (PLSLR) analyses were performed to examine the relationships between each response variable, CH and CRF, and the predictor variables age, corneal curvature (CC), axial length (AL), CCT and IOP.


RESULTS
CH was positively associated with CCT and negatively associated with age (scaled coefficients: CCT 0.62, p < 0.0001; age -0.55, p <0.0001; r2 = 0.25). CRF was positively associated with CCT and DCT IOP and negatively associated with age and AL (scaled coefficients: CCT 0.89, p < 0.0001; DCT IOP 0.46, p < 0.01; age - 0.60, p < 0.0001; AL -0.37, p < 0.01; r2 = 0.43). There was no significant association between CC and CH or CRF.


CONCLUSIONS
The study suggests that age and CCT are strongly associated with CH and CRF, and that the latter is also influenced by AL and IOP. However, the variables studied could explain only 25% and 43% of the measured variation in CH and CRF, respectively, suggesting other factors also affect the values of these measurements.
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 11-43, Bath Street, London EC1V 9EL, UK. aachal.kotecha@ucl.ac.uk.
Aachal
A
Kotecha
Richard A
RA
Russell
Angelos
A
Sinapis
Sayeh
S
Pourjavan
Dimitros
D
Sinapis
David F
DF
Garway-Heath
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D058452:Axial Length, Eye / Q000502:physiology; D001696:Biomechanical Phenomena; D003315:Cornea / Q000033:anatomy & histology / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011446:Prospective Studies; D012044:Regression Analysis; D014065:Tonometry, Ocular; D055815:Young Adult