title: Ocular tissue imaging using ultrahigh-resolution, full-field optical coherence tomography.
abstract: 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.
authors.affiliation: Laboratoire d'Optique Physique, Ecole Supérieure de Physique et Chimie Industrielles, Centre National de la Recherche Scientifique, Paris, France. grieve@optique.espci.fr
authors.forename: Kate
authors.initials: K
authors.lastname: Grieve
authors.forename: Michel
authors.initials: M
authors.lastname: Paques
authors.forename: Arnaud
authors.initials: A
authors.lastname: Dubois
authors.forename: José
authors.initials: J
authors.lastname: Sahel
authors.forename: Claude
authors.initials: C
authors.lastname: Boccara
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Le Gargasson
mesh_terms: 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*