Abstract
Purpose: :
Full-field OCT (FF-OCT) is an ultra-high resolution OCT technique which is considered to be suitable for imaging of cornea at a cellular level. This study was conducted to verify the feasibility of FF-OCT in the imaging of stroma of ex vivo porcine cornea.
Methods: :
The FF-OCT setup used in the study was based on a Linnik type interference microscope where a horizontal cross-sectional image is detected with a two-dimensional CCD camera. A Halogen lamp is used as the broadband source which offers a 2µm depth resolution in tissue. The lateral resolution is limited by the objective lens (NA=0.5) as 1µm. Images were obtained through the stroma in ex vivo porcine cornea. The area ratio (%) of keratocyte and the density of fibrillar structure in the FF-OCT image are compared between the superficial layer and deep layer of the stroma.
Results: :
Different from that observed with a confocal microscope, the nucleus of keratocyte was observed as low-intensity area and cytoplasm was observed as high-intensity area. The area ratio (%) of keratocyte was significantly larger at superficial stroma (53.0±19.5) than that at the deep layer (27.1±14.4; p=0.031, paired-t test) Moreover, a well defined fibrillar structure which might possibly be associated with the arrangement of collagen was observed as well. There was a significant difference in the density (line/mm2) of fibrillar structure between the superficial layer (14.7±20.3) and the deep layer (580.0±109.5; p=0.001, paired-t test).
Conclusions: :
FF-OCT might be used as the OCT microscope for the observation of corneal stroma, where it may offer additional information that is different from that observed with a confocal microscope such as a high-intensity cytoplasm of the keratocyte and fibrillar structure.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non-clinical