Boris Gramatikov, Ph.D.
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I am a member of the Hopkins faculty since 1996, and am currently Assistant Professor in the Division of Pediatric Ophthalmology and Adult Strabismus at The Wilmer Eye Institute. I am a biomedical engineer with expertise in medical instrumentation, opto-electronics, computers, signal processing, lasers and biomedical optics. My present research interests are in retinal birefringence scanning, eye tracking, automated focus detection, fixation stability and other related fields, including translational research. Our main goal is to identify and treat children with strabismus (misaligned eyes) or anisometropia (unequal refractive error) before irreversible amblyopia (functional monocular blindness) results.
Please click here for my institutional web page at the Wilmer Eye Institute, or scroll down for more …
Volunteering: I have chaired the
Baltimore Chapter of the IEEE-EMBS (Institute of
Electrical and Electronics Engineers, Engineering in Medicine and Biology
Society), which is a part of the
Baltimore Section of the IEEE. I chaired the Section in 2006, and am
presently an ExCom
member and The Section’s Director
for Education Activities and Continuing Education (CEEE). Click here
for a list of past
and planned future CEEE events. For more
on volunteering in professional societies, please check out my CV.
Recent
funding. In 2009 I received the The Hartwell Foundation Individual Biomedical Research
Award for work on
the Pediatric
Vision Screening Instrument for Early Detection of Amblyopia (Lazy Eye). Click here for
all 2009 awards. Read
the related article in the JHU Gazette…
I and my co-workers from Duke
University 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. Read more…
Main 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. Click here
for details as posted on the Foundation’s website.
Retinal birefringence scanning and optical coherence tomography. This is a collaboration project between Johns Hopkins and Duke University, sponsored by The Hartwell Foundation. Both PIs, Dr. Cynthia Toth and Dr. Boris Gramatikov, have successfully completed previous individual research projects sponsored by the foundation. The goal of the present research project is to further improve these two technologies and combine them with the aim of enhancing the current ability to determine levels of retinal disease in infants and children, and to better identify likelihood of disease progression. Read more…
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.
More about me (scroll down)
The
Pediatric Vision Screener
The Pediatric
Vision Screener – early prototype (2000-2001)
The Pediatric Vision Screener – advanced prototype (2010-2012)
Click here to go to my educational web page containing important information about my work and the methods and technology used in my research and R&D.
Current work on the
Pediatric Vision Screener
Using computer modeling, optical technologies, modern electronic hardware, novel signal processing and optimization methods, we continue to improve the Pediatric Vision Screener, with the goal of making it a reliable, clinically relevant, market-oriented, and competitive product.
Some spin-off products: a vision scanner using non-moving parts, a biometric (security) scanner using the birefringent properties of the retina around the optic nerve, detection of ADHD, and others (please see publications).
More about me:
This page was last updated in 2016