Abstract
Purpose: :
To demonstrate the feasibility of a sub-cellular level retinal imaging application using a newly developed full-field optical coherence tomography (FF-OCT) system.
Methods: :
To achieve retinal imaging with a FF-OCT system that we have recently developed for video-rate cellular level imaging in biological tissues (M.Akiba and K.P.Chan, J. Biomed. Opt., in press, 2007), water immersion objectives suitable for retinal imaging were newly designed. As a feasibility study, a simple model eye consisting of a curved acrylic plate as a cornea and a convex lens as a crystalline lens was manufactured to simulate the refraction of a human eye. The model eye was placed in a small container filled with water, and the microscope objective was lowered to the container, where the tissue sample was placed at the fundus plane.
Results: :
The transverse resolution was evaluated to be ~4 µm by placing a USAF resolution test target at the fundus plane that was approximately 24 mm apart from the cornea surface of the model eye. The axial resolution was ~3 µm in water as determined by the source bandwidth. The field of view of the present setup was set to 600 µm x 600 µm. Ex vivo porcine retinal tissues were examined. Although retinal nerve fiber layer is depicted as uniformly highly-reflective layer in conventional OCT, it was observed as bundles of highly-reflective fibers in FF-OCT, probably representing retinal nerve fibers.
Conclusions: :
The feasibility of retinal imaging using a real-time FF-OCT system incorporated with a newly designed water immersion objective was studied using a model eye. Further modification of the current system may lead to sub-cellular level imaging of human retina in vivo.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • nerve fiber layer