24.03.2023

Multi-spot measurements of air-induced corneal deformations (IMCUSTOMEYE project)

The IMCUSTOMEYE project involves the cooperation of 10 partners, both academic and industrial, began in 2018. From day one, as a consortium, we have focused on developing new, non-invasive, imaging-based methods to change the paradigm in the diagnosis and treatment of various eye diseases.

POB group’s researchers, were tasked with constructing a compact, low-cost device to measure 3D dynamic corneal deformation of the human eye. As it is in life, and especially in physics, we had to make some compromises with respect to the prototype being constructed. Even if full three-dimensional imaging of a corneal deformation process lasting only 20 ms is possible, it would require considerable complication of the measurement system and generate unacceptable costs. We proposed an intermediate solution of simultaneous measurements at multiple points on the cornea, including the center of the cornea and 4 pairs of points placed opposite along 4 directions (horizontal, vertical and corresponding directions rotated by 45 degrees). This approach made it possible to prepare a prototype compact system to be placed in an eye clinic. In addition, we preliminarily verified the possibility of both further miniaturization of the system and the potential for a significant reduction in manufacturing costs.

Clinical prototype

Our clinical prototype has not only survived the 300+ kilometer trip to the clinic in Bydgoszcz, Poland, but has also measured more than 100 eyes to date. It is worth noting that the prototype has been prepared from the hardware and software side in such a way that it could be successfully operated by eye clinic staff.

To analyze the data, we extract temporal corneal deformation for each spot. The biomechanical asymmetry can be assessed by comparison of opposite spots. To provide more intuitive presentation of the results, we introduced “asymmetry vector” that can be plotted for any deformation parameter (e.g., displacements amplitudes, deformation area, deformation slopes). For each pair of opposite spots, we create a vector pointing towards spot with higher value of selected parameter with a magnitude given by the differences of values for both spots in pair.

Data analysis pipeline

Having vectors for all 4 pairs of spots we can calculate overall vector to show global effect. This approach was applied already to some of our early clinical data to show differences in biomechanical asymmetry between healthy and keratoconus corneas (presented here for displacement amplitude and area).

Early clinical results

Text: Dr. Karol Karnowski

TEAM:

Karol Karnowski, PhD

Jadwiga Milkiewicz, MSc

Angela Pachacz, Eng

Onur Cetinkaya, BEng

Rafał Pietruch, Eng

Andrea Curatolo, PhD

Prof. Maciej Wojtkowski

Publications:

  1. D. Alonso-Caneiro, K. Karnowski, B. Kaluzny, A. Kowalczyk, and M. Wojtkowski, “Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system”, Optics Express, Vol. 19, Issue 15, pp. 14188-14199 (2011)
  2. S. Marcos, C. Dorronsoro, K. Karnowski, M. Wojtkowski, „Corneal biomechanics From Theory to Practice: OCT with air puff stimulus”, Kugler Publications 2016, edited by C.J. Roberts, J. Liu
  3. K. Karnowski, E. Maczynska, M. Nowakowski, B. Kaluzny, I. Grulkowski, M. Wojtkowski, “Impact of diurnal IOP variations on the dynamic corneal hysteresis measured with air-puff swept-source OCT”, Photonics Letters of Poland, (2018)
  4. E. Maczynska, K. Karnowski, K. Szulzycki, M. Malinowska, H. Dolezyczek, A. Cichanski, M. Wojtkowski, B. Kaluzny and I. Grulkowski, “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 (2019)
  5. A. Curatolo, J. S. Birkenfeld, E. Martinez-Enriquez, J. A. Germann, G. Muralidharan, J. Palací, D. Pascual, A. Eliasy, A. Abass, J. Solarski, K. 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)