In-vivo corneal pulsation in relation to in-vivo intraocular pressure and corneal biomechanics assessed in-vitro. An animal pilot study. (September 2017)

• Record Type: Journal Article
• Authors: Rogala, Maja M.; Danielewska, Monika E.; Antończyk, Agnieszka; Kiełbowicz, Zdzisław; Rogowska, Marta E.; Kozuń, Marta; Detyna, Jerzy; Iskander, D. Robert
• Is Part Of: Experimental eye research. Volume 162(2017)
• Page Start: 27
• Page End: 36
• Publication Date: 2017-09
• Subjects: Corneal biomechanics -- Intraocular pressure -- Corneal pulse -- Spectral analysis; Ophthalmology -- Periodicals; Eye -- Periodicals; Œil -- Périodiques; Ophthalmology; Periodicals; Electronic journals; 612.8405
• DOI: 10.1016/j.exer.2017.07.003
• Languages: English
• ISSNs: 0014-4835

Abstract

Abstract: The aim was to ascertain whether the characteristics of the corneal pulse (CP) measured in-vivo in a rabbit eye change after short-term artificial increase of intraocular pressure (IOP) and whether they correlate with corneal biomechanics assessed in-vitro. Eight New Zealand white rabbits were included in this study and were anesthetized. In-vivo experiments included simultaneous measurements of the CP signal, registered with a non-contact method, IOP, intra-arterial blood pressure, and blood pulse (BPL), at the baseline and short-term elevated IOP. Afterwards, thickness of post-mortem corneas was determined and then uniaxial tensile tests were conducted leading to estimates of their Young's modulus ( E ). At the baseline IOP, backward stepwise regression analyses were performed in which successively the ocular biomechanical, biometric and cardiovascular predictors were separately taken into account. Results of the analysis revealed that the 3rd CP harmonic can be statistically significantly predicted by E and central corneal thickness (Models: R 2 = 0.662, p < 0.005 and R 2 = 0.832, p < 0.001 for the signal amplitude and power, respectively). The 1st CP harmonic can be statistically significantly predicted by the amplitude and power of the 1st BPL harmonic (Models: R 2 = 0.534, p = 0.015 and R 2 = 0.509, p < 0.018, respectively). For elevated IOP, non-parametric analysis indicated significant differences for the power of the 1st CP harmonic (Kruskal–Wallis test; p = 0.031) and for the mean, systolic and diastolic blood pressures (p = 0.025, p = 0.019, p = 0.033, respectively). In conclusion, for the first time, the association between parameters of the CP signal in-vivo and corneal biomechanics in-vitro was confirmed. In particular, spectral analysis revealed that higher amplitude and power of the 3rd CP harmonic indicates higher corneal stiffness, while the 1st CP harmonic correlates positively with the corresponding harmonic of the BPL signal. Highlights: In-vivo corneal pulse (CP) is linked to in-vitro corneal biomechanics. Higher power of the 3rd CP frequency harmonic indicates increased corneal stiffness. Elevated intraocular pressure differentiate spectral distribution of CP signal.