Gramatikov, Boris

Dr. Gramatikov is the 2006 Past Chair of the Baltimore Section of the IEEE (Institute of Electrical and Electronics Engineers.  Presently he is the Section's Director for Education Activities and Continuing Education. He has also chaired the Baltimore Chapter of the IEEE-EMBS (Engineering in Medicine and Biology Society).

In 2009, Dr. Gramatikov received the The Hartwell Foundation Individual Biomedical Research Award for work on the Pediatric Vision Screening Instrument for Early Detection of Amblyopia (Lazy Eye). Read the related article in the JHU Gazette. 

Dr. Gramatikov and team recently received a Biomedical Research Collaboration Award from the Hartwell Foundation for developing advanced technology for diagnosing retinal abnormalities in infants and toddlers, in collaboration with Duke University. Read the JHU announcement.

Current Projects:

Retinal birefringence scanning utilizes the optical polarization properties of the human retina. This method was developed originally by Dr. David Guyton and Dr. David Hunter ("Automated detection of eye fixation by use of retinal birefringence scanning", Applied Optics 38,OT&BO:1273-9, March 1999), and is related to the Haidinger brush phenomenon - a bow-tie or propeller-like pattern that appears to rotate about the fixation point when a polarizing filter is placed over the eye and rotated. This phenomenon reflects the retinal nerve fiber axon arrangement about the fovea and can be utilized in a variety of useful applications. In our settings, foveal fixation is monitored in human subjects remotely and continuously by use of a noninvasive retinal scan. Polarized near-infrared light is imaged onto the retina and scanned in a 3-deg annulus at frequency f. Reflections are analyzed by differential polarization detection. The detected signal is predominantly of frequency 2f during central fixation, and f during paracentral fixation. Phase shift at f correlates with the direction of eye displacement. Mathematical modeling of birefringence in retinal birefringence scanning has confirmed the experimental and clinical results. Potential applications of this technique include screening for eye disease, eye position monitoring during clinical procedures, and use of eye fixation to operate devices. Considering that the structure of the fovea is the basis of the retinal birefringence scan signal, the experience gained from bringing retinal birefringence scanning to the clinic will also increase our understanding of foveal structure in health and other forms of disease.  Dr. Gramatikov is involved in the design of a portable Bilateral Retinal Birefringence Scanner (BRBS) with improved noise performance, to be used as a pediatric vision screener. The new design incorporates binocular foveal birefringence scanning, and separate channels for binocular focus detection. This combination of focus and alignment detection should identify over 95% of all children at risk for amblyopia. This work is being performed in the past in collaboration with AURA (Association of Universities for Research in Astronomy, Inc.), the Space Telescope Science Institute and the Instrument Development Group (IDG) at the Department of Physics and Astronomy at the Johns Hopkins University. This project was supported generously by The Hartwell Foundation with the 2009 Individual Biomedical Research Award.

Retinal birefringence scanning combined with optical coherence tomography: Today, when a retinal condition is suspected in an infant or toddler, the challenge to the ophthalmologist is to enable a child to achieve and maintain ocular fixation during examination. To obtain a precise retinal examination, the choices are placing a child under general anesthesia (with many risks, such as pneumonia and potential death), perform a limited examination, or worse, to wait until the child grows older to identify what is wrong. For adults, where fixation and cooperation are usually not an issue, a technology known as optical coherence tomography (OCT) is used to provide high speed, 3-dimensional, and magnified cross-sectional images of the retina (e.g., images depicting macula). This standard of care for outpatient diagnosis and management of retinal disease in adults is well-tolerated in older children. Unfortunately, the size of a conventional OCT device is too large for deployment in an infant care setting. Because of The Hartwell Foundation's support to Dr. Toth, a state-of-the-art handheld OCT imaging device has now been shown to be valuable in the assessment of premature and newborn infants, but the apparatus must be held less than one inch from the eye to achieve proper ocular alignment. Most neonates can be adequately immobilized for retinal imaging, although not perfectly so. Infants, active toddlers and young children will not cooperate for such imaging and thus a more suitable version of the hand-held OCT instrument is desperately needed. Of concern is also the quality of data, acquired during only short-lasting episodes of central fixation (when the child’s eyes are looking in the right direction). It is distressing that treatable retinal conditions in young children are frequently missed because of this situation. To overcome the limitations of current technology, Drs. Toth at Duke and Gramatikov at Johns Hopkins were supported with a 2012 Biomedical Research Collaboration Award by The Hartwell Foundation collaboration. They and their collaborators are developing a swept-source optical coherence tomography (SSOCT) retinal imaging system that is 10 times faster than current high speed OCT systems, works from a comfortable viewing distance, and based upon retinal birefringence scanning (RBS) technology offered by Drs. Gramatikov, Guyton and Irsch, will automatically detect central fixation. A second generation Pediatric Vision Screener using RBS has already been developed with funding from The Hartwell Foundation. The new system will have the unsuspecting child view a cartoon on a small LCD computer screen, with no distracting apparatus between the child and the screen. The examiner will be able to retain optical alignment of the SSOCT device with the child’s eye while invisible polarized light automatically detects when the eye is looking at specific targets on the computer screen. Our goal will be a clinically suitable imaging method for diagnosing retinal diseases and monitoring the progression or response to ocular therapy without a need for sedation or anesthesia. We believe that SSOCT will have the power to transform the current ability to determine levels of retinal disease in infants and children and likelihood of disease progression.

Determination of ocular defocus using the double-pass blur image of a point source of light: The double-pass blur image of a point source is used to determine the quality of focus of the human eye. This project is based on earlier work by Dr. David Guyton, Dr. David Hunter and Nainesh Gandhi. An apparatus that can determine a threshold of defocus was devised using a circle/annulus (bulls-eye) photodiode that can distinguish focused from defocused light. A monochromatic near-infrared light source (laser diode) is employed. The light reflected from the fundus of the eye is projected by a beamsplitter onto the bulls-eye detector, which is optically conjugate to the laser diode. The photodetector signal obtained is a function of the amount of defocus caused by the double-pass point spread reflected from the retina. The signal is affected by refractive error, incomplete accommodation, media opacities, and abnormalities of retinal reflection. One of the major risk factors for amblyopia is refractive error, or, more accurately, the degree of defocus the eye experiences. The defocus is perhaps best quantified by measuring the size of the retinal blur circle. Such defocus detection can be combined with eye-fixation monitoring to be used as a screening tool to detect risk factors for amblyopia.

Read Dr. Gramatikov's CV