The influence of hydration on different mechanical moduli of the cornea.

Seiler, Theo G.; Shao, Peng; Früh, Beatrice E.; Yun, Seok-Hyun; Seiler, Theo (2018). The influence of hydration on different mechanical moduli of the cornea. Graefe's archive for clinical and experimental ophthalmology, 256(9), pp. 1653-1660. Springer 10.1007/s00417-018-4069-7

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PURPOSE To determine the interrelation of different elastic moduli of the cornea and to investigate their dependency on corneal hydration. METHODS Rabbit eyes were divided into four groups. Corneas were excised and mounted into a Barron artificial anterior chamber. Various corneal hydration steady states were achieved with different dextran T-500 concentrations in the anterior chamber, as well as on the corneal anterior surface. The treatment-solutions of each group contained either 5, 10, 15, or 20% w/w dextran. Ultrasound pachymetry was used to measure central corneal thickness. Brillouin microscopy of the central cornea determined the longitudinal bulk modulus by means of Brillouin frequency shift. Subsequently, a 5-mm-wide central strip was taken for extensiometry to measure the tangential elastic modulus. RESULTS The longitudinal bulk modulus was 1.2-times higher in corneas dehydrated with 20% dextran compared to those hydrated with 5% dextran. In contrast, the tangential elastic modulus increased by 4.4 times. The obtained longitudinal bulk moduli were two orders of magnitude bigger than the tangential elastic moduli. Regression analysis of longitudinal bulk modulus and tangential elastic modulus revealed a quadratic relation. The bulk modulus seemed to be independent of tension, whereas the elastic modulus was tension-dependent. Greater corneal hydration led to significantly thicker pachymetry. CONCLUSION Corneal biomechanics are highly dependent on the level of corneal hydration. Surprisingly, tangential elastic moduli were more sensitive to hydration changes than longitudinal bulk moduli. A quadratic relation was found between both moduli.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ophthalmology

UniBE Contributor:

Seiler, Günter Theodor Michael and Früh Epstein, Beatrice


600 Technology > 610 Medicine & health
500 Science > 530 Physics








Günter Theodor Michael Seiler

Date Deposited:

07 Mar 2019 16:15

Last Modified:

12 Dec 2019 13:42

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Biomechanics Brillouin Cornea Extensiometry Hydration Longitudinal elastic modulus Stress strain Tangential elastic modulus




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