Abstract
Purpose:
The purpose of this pilot study was to evaluate the ability to create a 360-degree image montage of the human limbus acquired in-vivo with spectral domain optical coherence tomography (SD-OCT) and to depict the circumferential configuration of the palisades of Vogt from those images.
Methods:
A commercial SD-OCT (Cirrus HD OCT, Carl Zeiss Meditec, Dublin, CA; 512x128 Anterior Segment Scan) was used to acquire image volumes of the corneal limbus in twelve clock hours from ten consented normal volunteers and from whole human corneal rims. Rims were imaged three times to determine the reproducibility of the reconstructions. Image volumes were analyzed with custom software to visualize the area of the epithelial basement membrane. Resulting images were stitched together to display the full circumference of the limbus and to describe the palisade patterns.
Results:
Reconstruction of 3D image volumes and segmentation of the epithelium provides a global portrait of the configuration of the palisades of Vogt. Palisade patterns described are consistent with those described previously with laser scanning confocal microscopy and clinical confocal microscopy, but OCT allows the first non-contact imaging of the full limbal area. Inferior regions display the most homogenous and consistent palisade structures with superior regions also showing clear structures. Nasal and temporal areas show some smaller palisade structures that are less regular and defined than superior and inferior regions.
Conclusions:
This preliminary study demonstrates that OCT is capable of producing 360-degree images of the palisades of Vogt in-vivo with existing FDA approved equipment. As the resolution of OCT volumes increases the clarity of these images will improve. 360-degree mapping of the palisades allows us for the first time to gain an overview of the full palisade field and will enable more comprehensive characterization of the morphology of the palisades at different stages of life and may be able to assist in surgical guidance. Larger datasets will be required to determine whether palisade configuration can be used as a diagnostic tool. The non-contact nature of OCT allows for repeated imaging without discomfort or hazard to the patient, which offers the possiblity temporal tracking of the presence of palisades. Further exploration and refinement of this technique is warranted.
Keywords: 482 cornea: epithelium •
550 imaging/image analysis: clinical •
479 cornea: clinical science