Abstract
Purpose :
Limbal stem cell deficiency results in breakdown of the corneal epithelium, corneal pannus, and chronic inflammation which can result in vision loss, chronic pain, and keratoplasty failure. Currently no reliable method exists to quantitate limbal stem cells located in the palisades of Vogt (POV) either in the clinical patient or in donor transplant tissue. Ability to assess these regions could potentially aid in donor tissue selection. We hypothesize that optical coherence tomography (OCT) could be used to develop a 360 degree structural map of the corneal limbus enabling us to image and quantify the POV in donor corneal tissue.
Methods :
OCT imaging was performed using a 20 kHz handheld spectral domain OCT (Bioptigen/Leica EnVisu 2300) with a custom short focal length lens attachment to increase lateral resolution. Individual volumes were acquired at 2000 A scans x 120 B scans over 3 mm x 1.5 mm. Imaging of the limbus of 14 corneo-scleral donor tissues was performed by placing the tissue on a rotating platform stage allowing 360° imaging of the tissue in 30° increments. Summed voxel projections were generated from each volume and the full 360 en face view was reconstructed in Matlab. For histologic confirmation, one corneal rim positive for POVs on OCT was submitted to pathology. Wilcoxon rank-sum test was used to test significance of differences.
Results :
POV were visible with OCT at the limbus in 6 of the 14 corneo-scleral rims. The mean number of palisade ridges was 58 ± 34.17 (mean ± SD) per cornea. The POV were predominantly found in the superior and inferior limbus (p<0.05). The mean donor age in corneas with POV was 55 years (n=6) as compared to 76 years (n=8) in corneas where POV were not visualized (p=<0.05). Histology of one of the POV+ OCT specimens confirmed the presence of POV in the sample.
Conclusions :
OCT is a useful non-invasive and non-destructive technique to image and quantify the POV in donor corneas and may be able to aid in selection of donor corneal tissue for limbal stem cell transplants with the goal of improving surgical outcomes in the future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.