A decade ago, two scientists from our Institute – prof. Wojtkowski and dr Karnowski – published the world’s first air-puff Optical Coherence Tomography research . The proposed method for direct measurements of apex corneal deformation was explored in several follow-up studies [2-4].
Over the last 4 years, prof. Wojtkowski and dr Karnowski lead locally (at the Institute of Physical Chemistry Polish Academy of Sciences) a group of researchers within the IMCUSTOMEYE – a 4-year project funded by the European Commission’s Horizon 2020 Programme under the Photonics 2017 KET topic. The IMCUSTOMEYE project focuses on the progress of the space of the air-puff OCT method towards three-dimensional measurements . The ultimate goal is to enable the characterization of the ocular mechanical behavior in vivo using a cost-effective imaging technology that provides results in almost real-time. The techniques will enable the construction of patient-specific models that can predict with high accuracy the mechanical response of eyes to disease and treatment.
Our role, as experts in biomedical optics and photonics, is to develop compact, affordable OCT device to image dynamic corneal deformation in a three-dimensional manner.
 David Alonso-Caneiro, Karol Karnowski, Bartlomiej J. Kaluzny, Andrzej Kowalczyk, and Maciej Wojtkowski, “Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system,” Opt. Express 19, 14188-14199 (2011)
 Carlos Dorronsoro, Daniel Pascual, Pablo Pérez-Merino, Sabine Kling, and Susana Marcos, “Dynamic OCT measurement of corneal deformation by an air puff in normal and cross-linked corneas,” Biomed. Opt. Express 3, 473-487 (2012)
 Maczynska, E, Karnowski, K, Szulzycki, K, et al. Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air-puff optical coherence tomography and corneal hysteresis. J. Biophotonics. 2019; 12:e201800154
 Karol Marian Karnowski, Ewa Mączyńska, Maciej Nowakowski, Bartłomiej Kałużny, Ireneusz Grulkowski, Maciej Wojtkowski, “Impact of diurnal IOP variations on the dynamic corneal hysteresis measured with air-puff swept-source OCT”, Phot. Lett. Pol., vol. 10, no. 3, pp. 64-66, (2018)
 Andrea Curatolo, Judith S. Birkenfeld, Eduardo Martinez-Enriquez, James A. Germann, Geethika Muralidharan, Jesús Palací, Daniel Pascual, Ashkan Eliasy, Ahmed Abass, Jędrzej Solarski, Karol Karnowski, Maciej Wojtkowski, Ahmed Elsheikh, and Susana Marcos, “Multi-meridian corneal imaging of air-puff induced deformation for improved detection of biomechanical abnormalities,” Biomed. Opt. Express 11, 6337-6355 (2020).
Author: Karol Karnowski, PhD
Estimation of scleral mechanical properties from air-puff optical coherence tomography
David Bronte-Ciriza, Judith S. Birkenfeld, Andrés de la Hoz, Andrea Curatolo, James A. Germann, Lupe Villegas, Alejandra Varea, Eduardo Martínez-Enríquez, and Susana Marcos
We introduce a method to estimate the biomechanical properties of the porcine sclera in intact eye globes ex vivo, using optical coherence tomography that is coupled with an air-puff excitation source, and inverse optimization techniques based on finite element modeling. Air-puff induced tissue deformation was determined at seven different locations on the ocular globe, and the maximum apex deformation, the deformation velocity, and the arc-length during deformation were quantified. In the sclera, the experimental maximum deformation amplitude and the corresponding arc length were dependent on the location of air-puff excitation. The normalized temporal deformation profile of the sclera was distinct from that in the cornea, but similar in all tested scleral locations, suggesting that this profile is independent of variations in scleral thickness. Inverse optimization techniques showed that the estimated scleral elastic modulus ranged from 1.84 ± 0.30 MPa (equatorial inferior) to 6.04 ± 2.11 MPa (equatorial temporal). The use of scleral air-puff imaging holds promise for non-invasively investigating the structural changes in the sclera associated with myopia and glaucoma, and for monitoring potential modulation of scleral stiffness in disease or treatment.
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