Abstract
Purpose :
To explore the capability of en face optical coherence tomography (OCT) in measuring the dimensions of the limbal palisades of Vogt complex (PVC) and describe the regional differences in healthy subjects.
Methods :
Retrospective analysis of limbal en face OCT images from 10 eyes of 10 healthy individuals. The best quality image from all available regions (nasal, temporal, superior, inferior) were selected for each subject. PVC was defined as the hyporeflective tissue within the anatomical limbus, including the palisades of Vogt and the surrounding limbal epithelium. Three-dimensional en face scans through the PVC, of 9µm depth each, were assessed to determine the anterior and superficial borders (end of Bowman’s layer) and the posterior and deep borders (transition of hyper-hyporeflective sclera-limbus). The area and volume of each scan were measured manually with ImageJ (Figure 1). Minimum and maximum depth were determined as the first and last appearance of the PVC on the OCT device, respectively. Statistical models were performed to account for different scans of the same eye and age.
Results :
A total of 10 nasal, 10 temporal, 5 superior and 5 inferior en face OCTs regions were assessed. Mean age was 39.5±13.6 years [26-77] with equal male-to-female ratio. En face OCT PVC was detected in all regions. PVC area, volume, maximum area, maximum depth and thickness were greater in the superior and inferior limbus compared to the nasal and temporal (1.18±0.10 and 0.68±0.05mm2, p=0.003; 3.15±0.24 and 1.90±0.19mm2, p<0.001; 0.17±0.02 and 0.06±0.01mm3, p<0.001; 129.4±5.0 and 107.7±3.4µm, p=0.002; and 63.4±3.8 and 44.7±4.2µm, p<0.001; respectively). PVC minimum depth was not statistically significant between the regions (62.5±3.1 and 69.0±12.2µm, p=0.116; respectively). Age was not a significant covariate in this study.
Conclusions :
Superior and inferior PVC area, maximum area, volume, maximum depth and thickness were greater than nasal and temporal PVC, in accordance to previous histopathological reports on regional stem cell density. En face OCT can provide novel and potentially clinical useful quantitative measurements to assess PVC health.
This is a 2021 ARVO Annual Meeting abstract.