Line-Field Optical Coherence Tomography as a tool for In vitro characterization of corneal biomechanics under physiological pressures

Abstract

There has been a lot of interest in accurately characterising corneal biomechanical properties under intraocular pressure (IOP) to help better understand ocular pathologies that are associated with elevated IOP. This study investigates the novel use of Line-Field Optical Coherence Tomography (LF-OCT) as an elastographic tool for accurately measuring mechanical properties of porcine corneas based on volumetric deformation following varying IOPs. A custom-built LF-OCT was used to measure geometrical and corneal surface displacement changes in porcine corneas under a range of IOPs, from 0–60 mmHg. Corneal thickness, elastic properties and hysteresis were calculated as a function of pressure. In addition, the effects of hydration were explored. We found that the elastic modulus increased in a linear fashion with IOP. Corneal thickness was found to reduce with IOP, decreasing 14% from 0 to 60 mmHg. Prolonged hydration in phosphate buffered saline (PBS) was found to significantly increase the elastic modulus and corneal hysteresis. Our study demonstrates that LF-OCT can be used to accurately measure the elastic properties based on volumetric deformation following physiological pressures. Furthermore, we show that prolonged hydration in PBS has a significant effect on the measured corneal properties.

Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM

“…Elastic modulus values of porcine corneas, reported in previous studies [52,53], is less than those measured by AFM (nano-scale). E of control corneas (whole thickness) tested by nanoindentation with a 100 µm flat punch [52] and inflation testing [53] were in the range of 40 to 700 kPa depending on testing conditions such as internal pressure and hydration. However, E measured on corneal sections (5 µm thick) in this study were in the range of 2 to 2.45 GPa.…”

Complete Removal of Arbitrarily Strong and Arbitrarily Located Auto Correlation Artifacts in Spectral Domain Optical Coherence Tomography: Demonstration of an Efficient and Cost Effective Technique

“…Experimental validation of our technique was done using a lab-made par-65 allel SD-OCT [22] instrument, also known as line-field OCT [23,24] as shown the null of the J 0 curve is clearly defined.…”

“…In conclusion, we have demonstrated a new technique for removal of autocorrelation which can work with arbitrarily strong and arbitrarily located autocorrelation artifacts. Our technique is specially suited for parallel or line-field FD-OCT devices[22,6,23,24] using spectrometers with 2-D sensors (cameras) which result in single-shot B-scans.Funding This work was not funded by any grant. Our department had infrastructure funding from the Department of Science and Technology, Government of India (DST) -DST FIST 2012-2017 SR/FST/PSI-172/2012.…”

Low Cost Open-Source OCT Using Undergraduate Lab Components

“…Instead, we explore a way to use the two-dimensional camera sensor in a parallel spectrometer design. The schematic of a parallel FD-OCT [14,15] setup, also known as line-field OCT [16,17] is shown in Figure 6. Such a configuration captures data for a complete B-scan in a single frame captured by the camera.…”