UBM provides high resolution imaging of the front portion, or anterior segment, of the eye. It is able to achieve this high resolution, on the order of 50 microns (a micron is 1/1000 of a millimeter, or 1/2500 of an inch), by the use of high frequency ultrasound transducers. The procedure is similar to ultrasound procedures involving the heart (cardiac echography) or the examination of a baby prior to birth. The ultrasound probe is moved slowly over the surface of the eye, and images are recorded. Structures which can be seen in the normal eye include the cornea, anterior chamber, iris, posterior chamber, ciliary body, sclera, anterior lens capsule, the end of Descemet's membrane (Schwalbe's line), and the scleral spur. The two forms of glaucoma which have benefited the most from ultrasound biomicroscopy research are angle-closure glaucoma and pigment dispersion syndrome.
Spectral-domain optical coherence tomography is a noninvasive, noncontact, imaging technology capable of producing cross-sectional images of the living human retina with extremely high resolution (approximately 6 microns). This exciting new technology has the potential to revolutionize the early detection of glaucoma through it's ability to evaluate the nerve cells damaged in glaucoma. Scanning through the fovea in a normal eye reveals the internal limiting membrane, foveal depression, retinal layers, photoreceptor layer, and retinal pigment epithelium. Of particular clinical importance at the present time is the early and accurate detection and staging of macular holes, often a severe form of vision loss and in the localization of fluid accumulation within the retina, such as can be found in central serous retinopathy or diabetic maculopathy.
A cutting-edge 3-dimensional optic nerve imaging study using enhanced-depth imaging OCT was initiated in 2010. Conventional imaging devices have a limited ability to image the deep structures of the optic disc because of a depth-dependent decrease in sensitivity and scattering of light by pigment and blood. Enhanced-depth imaging OCT improves image quality of the deep posterior segment structures.
Using this new technology of enhanced depth imaging, we now can evaluate the deep optic nerve complex structures such as the lamina cribrosa, vascular structures, peripapillary choroid and sclera, and subarachnoid space around the optic nerve. Since all these structures have been implicated in the pathogenesis of glaucoma, this project is helping clinicians and researchers in detecting, conceptualizing and understanding the pathophysiology of glaucoma and other optic nerve head diseases.
Enhanced-depth imaging OCT is also used to investigate the structure and dimension of the conventional aqueous outflow pathway. Size of aqueous outflow pathway can be measured and number of drainage channels can be counted. Because the conventional aqueous outflow pathway is the key determinant of the intraocular pressure that is the most important risk factor for glaucoma, this study will enhance clinicians’ understanding of glaucoma pathophysiology and help them in decision making processes for aqueous outflow pathway surgeries.
Please feel free to use our images for educational purposes. Our only request is that you cite The Ocular Imaging Center/New York Eye and Ear Infirmary as the source when they are used in lectures or for other informational activities! A list of published research from the New York Eye and Ear Infirmary's Ocular Imaging Center is also available.
If you have any questions regarding ultrasound biomicroscopy, optical coherence tomography or the Ocular Imaging Center at the New York Eye and Ear Infirmary, please contact Robert Ritch, M.D., Jeffrey M. Liebmann, M.D. or Sung Chul Park, M.D.