Daniela Hagenasr is currently conducting research on artificial muscles at the Alan G. MacDiarmid NanoTech Institute.
Matthew Petroll is a Professor of Ophthalmology and Chair of the Graduate Program in Biomedical Engineering at University of Texas Southwestern Medical Center.
Download the poster (.pdf), which was originally shared at the IEEE Texas Medical Device Symposium, 2012
3-Dimensional Assessment of In Vivo Corneal Wound Healing using a Modified HRT-RCM Confocal Microscope
1Daniela Hagenasr and 2W. Matthew Petroll, Ph.D.
1Department of Molecular and Cell Biology, UT Dallas and 2Department of Ophthalmology and Biomedical Engineering Program, UT Southwestern Medical Center
Background: Confocal microscopy is ideally suited for studying corneal wound healing in vivo. The recently developed HRT Rostock Corneal Module (HRT-RCM) provides excellent resolution, contrast and optical sectioning capability – defining features of confocal microscopy. However, changing the focal plane over large distances requires rotating the thumbscrew objective housing by hand, which limits the ability to perform quantitative 3-D imaging.
Purpose and Methods: The purpose of this research was to develop and test both hardware and software modifications for the HRT-RCM to allow quantitative 3-D corneal scanning. To automate the HRT-RCM focusing mechanism, a PC-controlled rotational stepper motor drive was attached to the microscope housing. To test the system for quantitative imaging, rabbit corneas were scanned both before and 1, 3, 7 and 14 days after transcorneal freeze injury (FI), which damages all corneal cell layers. Continuous scans were made from the endothelium to the epithelium at a constant lens speed, while collecting images at a rate of 30 frames/second. Image sequences were read into a custom-developed program for depth calculation and measurement of sub-layer thicknesses. Estimates of corneal backscattering were obtained by measuring the area under intensity vs. depth curves.
Results and Conclusions: Following freeze injury, a significant increase in both corneal thickness and light scattering was measured, due to tissue edema. Prior to surgery, corneal stromal cells (keratocytes) maintain a quiescent, dendritic morphology. However, from 7 – 14 days after FI, keratocytes repopulating the damaged tissue assumed an elongated and interconnected fibroblastic morphology, and a dramatic increase in cellular light scattering was measured. Overall, this modified system provides high resolution 3-D image stacks from the full thickness rabbit cornea in vivo. These datasets can be used for interactive visualization of corneal cell layers, measurement of sub-layer thickness, and estimation of stromal backscatter (haze) during wound healing.
