Ocular tissue imaging using ultrahigh-resolution, full-field optical coherence tomography.
OBJECTIVE
Ultrahigh-resolution, full-field optical coherence tomography (OCT), which uses a white light source, allows bidimensional, noninvasive tomographic imaging without scanning. The goal of the present study was to apply full-field OCT to ocular tissue imaging in an attempt to explore the capabilities of the technique.


METHODS
This full-field OCT system uses a Linnik-type interferometer with a tungsten-halogen source. The spatial resolution is 0.9 x 0.7 microm (transverse x axial). Unstained tissue samples (cornea, lens, retina, choroid, and sclera) and whole, unfixed eyes of rat, mouse, and pig were examined under immersion. A charge-coupled device (CCD) camera recorded a pair of interferometric images that were combined to display en face (i.e., in the x-y plane) tomographic images in real time. The acquisition time per tomographic image, which includes summation of 10 raw images, was on the order of 1 s. Postprocessing allows volumetric navigation through the image stack as well as three-dimensional (3D) imaging.


RESULTS
Cellular-level resolution was achieved in isolated tissue samples. En face (x-y) images revealed corneal epithelial and stromal cells, lens fibers, nerve fibers, major vessels, and retinal pigment epithelial cells. In x-z reconstructions, cellular layers within the cornea and retina and arterioles and venules were clearly defined. Transscleral retinal imaging was achieved in albino animals.


CONCLUSIONS
Ultrahigh-resolution, full-field OCT allows cellular-level imaging of unstained ocular tissues with high penetration depth. Although the current system is unsuitable for clinical use, this simple technique has potential for in vivo ocular examination, for which a new system is currently under development.
Grieve
Kate
K
Laboratoire d'Optique Physique, Ecole Supérieure de Physique et Chimie Industrielles, Centre National de la Recherche Scientifique, Paris, France. grieve@optique.espci.fr
Paques
Michel
M
Dubois
Arnaud
A
Sahel
José
J
Boccara
Claude
C
Le Gargasson
Jean-François
JF
D019412:Anatomy, Cross-Sectional / Q000379:methods*; D000818:Animals; D002829:Choroid / Q000033:anatomy & histology; D003315:Cornea / Q000033:anatomy & histology; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005123:Eye / Q000033:anatomy & histology*; D007368:Interferometry; D007908:Lens, Crystalline / Q000033:anatomy & histology; D051379:Mice; D010781:Photography; D051381:Rats; D012160:Retina / Q000033:anatomy & histology; D012590:Sclera / Q000033:anatomy & histology; D013552:Swine; D041623:Tomography, Optical Coherence / Q000379:methods*