Columbia University Irving Medical Center, Department of Ophthalmology
635 West 165 St., Research Annex, Room 711, New York, NY 10032-3724
Because of the eye’s superficial location, it has long been a focus of imaging research. The Silverman lab continues this process by developing novel methods for ultrasound imaging the eye. Some methods recently developed in the lab include high-resolution measurement and mapping of the corneal layers, photoacoustic imaging and elastography. Most recently, the lab has been developing plane-wave imaging, in which linear array probes comprised of many (>100) independent transmit/receive elements emit unfocused wavefronts rather than the conventional approach in which a focused beam is scanned incrementally from position to position to form an image. This allows a huge increase in imaging speed: While standard clinical ophthalmic ultrasound systems acquire about 10 images per second, plane-wave imaging can acquire as many as 20,000 images per second. This capability allows a significant increase in sensitivity, but of greatest importance is that this enables imaging and measurement transitory motions, including blood-flow. We are now conducting clinical studies of ocular blood-flow in preeclampsia (a serious complication of pregnancy) and retinopathy of prematurity (a vision-threatening complication in low-birthweight, pre-term infants). We are also conducting preclinical studies of ocular blood-flow in glaucoma models. These studies include use of microbubble ultrasound contrast agents, which enhance visualization of flow. With contrast, we are developing ‘super-resolution’ methods to improve blood-flow image detail by an order of magnitude. In addition to their research, Dr. Silverman and Ms. Daly perform clinical diagnostic ultrasound imaging of the eye.
(as pictured above, left to right: Inez Nelson, Ron Silverman, Sue Daly, Raksha Urs)
Dr. Silverman has been involved in ultrasound research in ophthalmology for over 30 years. His research includes development of high-resolution imaging systems, studies of ultrasound safety and bioeffects, high-intensity ultrasound, blood-flow imaging, photoacoustics, and tissue characterization by use of signal-processing. He applies these techniques for studies of ocular disease in animal models and for clinical examinations. Read Dr. Silverman's full bio, here.
Raksha Urs, PhD
Raksha Urs is an Associate Research Scientist in the Department of Ophthalmology of Columbia University. She has a Bachelor of Engineering degree from Mysore University and Masters and Ph.D. degrees in Biomedical Engineering from the University of Miami. Her doctoral work at the Bascom Palmer Eye Institute with Jean-Marie Parel and Fabrice Manns focused on the dynamics of the lens and ciliary muscles during accommodation. At the Silverman Laboratory, she is developing methods for imaging ocular blood flow and perfusion using ultrasound plane-wave imaging for evaluation of glaucoma, preeclampsia, retinopathy of prematurity and other conditions that exhibit vascular changes in the eye. She has also worked on methods for early detection of keratoconus, evaluation of corneal cross-linking using biomechanical imaging of the cornea and trans-epithelial corneal cross-linking procedures.
Suzanne Daly, RN, BSN, CRNO, CDOS
Suzanne Daly has been involved in ophthalmology and ophthalmology research for over 37 years, initially as a nurse in the in-patient ophthalmology floor at New York-Presbyterian-Weill Cornell Medical Center. She became an ophthalmology research nurse in 1986, working with Calvin Roberts on the early use of non-steroidal anti-inflammatory medications for ophthalmic surgery. She later became ophthalmic research nurse/sonographer working with D. Jackson Coleman, M.D. and Ronald H. Silverman, Ph.D. This work included pioneering development of 3D ultrasound for ophthalmology, diagnosis of ocular malignancies and trauma. She left Weill-Cornell to work in private practice and in 2013 rejoined Drs. Coleman and Silverman at Columbia, where they continue to develop advanced ultrasound technologies for the evaluation and diagnosis of ophthalmic conditions as well as novel treatments for age-related macular degeneration and other macular dystrophies and degenerations.
Inez Nelson, BA, is a recent graduate of Binghamton University. She joined the Silverman lab as a Research Technician in 2019 and provides expert support in preclinical procedures and data organization and analysis.
Plane-wave ultrasound Doppler image of posterior pole of pre-term neonate. ONH=optic nerve head; CRA=central retinal artery; CRV=central retinal vein; SPCA=short posterior ciliary artery; Ch=choroidal artery; R=retina, Z=circle of Zinn.
Plane-wave B-mode image (left) and corresponding plane-wave Doppler image of posterior pole and orbit of a rat eye after intravenous injection of microbubble contrast agent. ON=optic nerve; CRA=central retinal artery; CRV=central retinal vein; VV=vortex vein; CA=ciliary artery.
Diagnostic ultrasound images of a 69 year old male with hypotony (low intraocular pressure). UBM image (left) reveals ciliary body effusion. 10 MHz B-scan (right) demonstrates choroidal detachment.