Conventional OCT generates one or few cross-sections of the retina and requires predetermination of measurement location and geometry. Because retinal pathologies are usually irregular and 3-dimensional in nature, a retinal imaging device with both high depth resolution and high lateral resolution is desired. The lateral resolution of the conventional OCT system is limited by sampling density, which in turn is limited by the speed of the system. In this paper, we present a three-dimensional optical coherence retinal tomograph (3D-OCT) which combines the rapid transversal imaging mode of a confocal scanning laser ophthalmoscope (cSLO) with the depth resolution of optical coherence tomography (OCT) to achieve high speed 3-D imaging. In contrary to the conventional OCT which performs adjacent A-scans to form a cross-section image (B-scan) perpendicular to the retinal surface, 3D-OCT acquires section images (C-scan) parallel to the retinal surface at defined depths across the thickness of the retina. Three-dimensional distribution of light-remitting sites within the retina is recorded at a depth resolution of ~12 μm (in eye) and lateral resolution of 10μm x 20μm within 1.2 seconds. In this paper, we present the results of in vivo retinal imaging of healthy volunteers and diabetic patients, retinal thickness mapping, and macular edema detection with the 3D-OCT device. Reproducibility of retinal thickness mapping ranges from 16 μm ~ 35 μm for different study subjects. Detailed retinal thickness map allows ready identification of location and area of macular thickening. C-scan images and continuous longitudinal cross section images provide visualization of pathological changes in the retina, such as presence of cyst formation and hard exudates. The need to predetermine measurement location and geometry is eliminated in 3D-OCT, in contrast to conventional OCT.
[1]
T. Dawber,et al.
The Framingham Eye Study monograph: An ophthalmological and epidemiological study of cataract, glaucoma, diabetic retinopathy, macular degeneration, and visual acuity in a general population of 2631 adults, 1973-1975.
,
1980,
Survey of ophthalmology.
[2]
J. Fujimoto,et al.
Optical coherence tomography of the human retina.
,
1995,
Archives of ophthalmology.
[3]
J. Cunha-Vaz,et al.
The blood-ocular barriers.
,
1979,
Survey of ophthalmology.
[4]
Michael Larsen,et al.
Diabetic macular edema assessed with optical coherence tomography and stereo fundus photography.
,
2002,
Investigative ophthalmology & visual science.
[5]
Laura Pastor Sanz.
High-speed optical delay line for optical coherence tomography
,
2004
.
[6]
Photocoagulation for diabetic macular edema. Early Treatment Diabetic Retinopathy Study report number 1. Early Treatment Diabetic Retinopathy Study research group.
,
1985,
Archives of ophthalmology.
[7]
Qienyuan Zhou,et al.
Three-dimensional imaging of the human retina by high-speed optical coherence tomography.
,
2003,
Optics express.
[8]
David J. Webb,et al.
Transversal and longitudinal images from the retina of the living eye using low coherence reflectometry.
,
1998,
Journal of biomedical optics.
[9]
T. Gardner,et al.
Diabetic retinopathy: more than meets the eye.
,
2002,
Survey of ophthalmology.