October 2009
Insight
Inside Imaging
Photographers take an intimate look at the eye
By Genevive Bjorn, M.S., NEI Freelance Science Writer
and Allyson T. Collins, M.S., NEI Science Writer/Editor
"Participating in research is one way of lighting a candle instead of cursing the darkness," says Cox, a patient at the NEI.
John Cox is something of a photography expert--but not from behind the camera's eyepiece. He has posed for thousands of images over the past decade, though the photographers aren't interested in his smile.
They zoom in on his eyes: his corneas at the front, which are cloudy from a condition called Fuchs' endothelial dystrophy; his lenses just behind the cornea, which are synthetic because surgeons removed his natural lenses affected by cataracts; and his retinas at the back of the eye, which have leaking blood vessels related to the wet form of age-related macular degeneration (AMD).
Cox, who is legally blind, visits the National Eye Institute (NEI) clinic in Bethesda, Md., on a monthly basis so his doctor, Wai Wong, M.D., Ph.D., can monitor these conditions through examinations and imaging. Though he's not enrolled in a clinical trial right now, Cox has participated in several during the past 10 years. These studies have made him well-acquainted with the NEI photographers and their various cameras.
"Participating in research is my way of lighting a candle instead of cursing the darkness," he says. "Maybe my participation will lead to a cure, so the next generations won't have to lose their vision. Even if my vision doesn't improve, the least I can do is sit here, pose for the photographers, and do my part to help."
Photographers in the NEI Imaging Services Section: (back row, l to r) Denise Cunningham, CRA, MEd, Alicia Zetina, CRA, and Marilois Palmer; (center) Michael Bono, CRA, COT
Tools of the trade
NEI's four ophthalmic photographers see patients who have any of hundreds of eye conditions, ranging from common to rare. On a busy day in the clinic, they may photograph the eyes of 20 patients with a variety of instruments, according to Denise Cunningham, CRA, MEd, chief of the NEI Imaging Services Section.
The ophthalmic photography workhorse is the digital fundus camera, which captures pictures of the retina in color or black and white. The confocal scanning laser ophthalmoscope takes imaging a step further, allowing Cunningham and her team to track blood flow through vessels within the retina and the underlying choroid tissue.
Photographers snap photos of the front of the eye, including the cornea and the lens, using a slit-lamp camera or an ordinary-looking single-lens reflex camera equipped with a macro lens for close-up work.
"The eye disease or condition dictates which tools we need to use and how much time the patient will spend getting photographed," Cunningham explains.These tools show the same subject--the eye--from different perspectives, revealing distinctive aspects of the same disease. Cunningham describes it as similar to looking at a mountain and appreciating the many ways to see it: in daylight, at night, in the rain, and through clouds. It's always the same mountain, but each perspective tells a different part of the story.
"The eye disease or condition dictates which tools we need to use and how much time the patient will spend being photographed," Cunningham explains.
NEI photographer Michael Bono uses the confocal scanning laser ophthalmoscope (cSLO). On the computer screen, an image from the cSLO shows the blood vessels of the choroid, the tissue below the retina.
A person with a retinal disorder such as AMD typically comes to the Imaging Services Section and receives dilating eye drops to widen his or her pupils, offering the photographers a better look inside. NEI photographers then take color photos to document what the doctor has found during the examination. They also perform autofluorescence imaging, which captures light emitted from the naturally occurring fluorescent molecules in both healthy and diseased eye tissue.
If doctors suspect that abnormal blood vessels are growing, such as in the wet form of AMD, the photographers may also be asked to shoot a rapid sequence of images showing blood flow in the eye. To identify abnormalities in the circulation of the retina, photographers use the fundus camera to record the presence of fluorescein dye in the blood vessels. This dye is injected into the patient's arm vein and travels into the eye's circulation.
To identify abnormalities in the circulation of the choroid, photographers use the confocal scanning laser ophthalmoscope to make a movie of indocyanine green dye moving through the eye's blood vessels. These high-contrast still frames or movies allow doctors to visualize and track the growth of abnormal blood vessels.
"Even though it can take a long time, the entire photography process is simple, and it doesn't bother me at all," Cox says.
Cultivating the craft
Because almost all NEI patients are involved in long-term research studies, photographers must carefully produce images of precisely the same location in each eye to document any changes between visits. But, as many of the photographers are also trained artists, the line between science and art occasionally blurs.
"We often take exquisitely beautiful images," Cunningham says.
Members of her staff, including Marilois Palmer, Alicia Zetina, and Michael Bono, have won numerous awards over the years for their blend of scientific and artistic work. Last year, Bono even took home a first place distinction from the Ophthalmic Photographers' Society for an image of Vogt-Koyanagi-Harada disease, a condition that causes eye inflammation.
Bono's award-winning stereo image of Vogt-Koyanagi-Harada disease, which destroys the retina.
Still, the images captured in the NEI clinic are above all for science, and on a recent afternoon, science is what brings Cox into the Imaging Section. He leans his chin and forehead against a padded rest, posing as Bono's latest subject.
"People come here to get the best care possible, which may require more than 100 different images to be taken using various wavelengths of light, so doctors can look at the intricacies of certain eye conditions," Cunningham says.
Cox passes the time by asking Bono photography-related questions: What is the name of the camera? How does it work? How are these pictures going to help the doctor? Do you mind if I look at them?
"The more you know about what you're undergoing, the more you understand," he explains. "And the more you understand, the less you fear about the process.
