Researchers publish super-resolution OCT retina scans to encourage development of AMD-diagnosis software
MARCH 20, 2009--An optical coherence tomography (OCT) system with twice the resolution of commercial OCT instruments is the cornerstone of an unprecedented project designed to shed new light on the development of age-related macular degeneration (AMD)--the leading cause of vision loss in Americans and Europeans over 50. The project involved research groups at three institutions, and produced ultra-detailed 3-D images of the eyes of more than 2000 people from different ethnic groups, one-fifth of whom have AMD. The study hopes to pave the way for new diagnostic software that might enable early treatments to halt vision loss.
The research groups of James Fujimotoat the Massachusetts Institute of Technology (MIT), along with Jay Duker of the Tufts University School of Medicine and Joel Schuman of the University of Pittsburgh School of Medicine, collaborated on the work. Selected electronic data are published in the special Interactive Science Publishing (ISP) issue of Optics Express, the Optical Society's (OSA) open-access journal.
Optical coherence tomography (OCT) has become a standard tool for assessing AMD and other eye diseases. Fujimoto's team used the super-resolution system to image the retinas of the 400 people suffering from different stages of macular degeneration, from mild to advanced.
Most of the patients suffer from "dry" AMD, the milder form, whose hallmark is drusens--small clumps that build up between the layers of retina. Ultra-high resolution OCT reveals the detailed structure of these changes with a resolution that enables individual layers of the retina to be visualized. "This would be hard to resolve with the standard resolution of a typical commercially available OCT instrument, which cannot see ultra-thin layers," says co-author Yueli Chen of MIT.
Scans of other patients' eyes show a more advanced "wet" form of AMD, in which abnormal blood vessels grow in between the layers of the retina. 3-D OCT provides a more accurate estimate of the volume of fluids leaked by these faulty vessels, which damages the photoreceptors in the eye and leads to blindness.
The MIT group is publishing the electronic data in these 3-D images in order to make it available to the image processing community to develop computer programs that can quickly and automatically detect the details and severity of the disease--by counting the number of drusens, for example, or quantifying the volume of fluid leaked into the eye by faulty blood vessels. Developing these programs will be difficult because of the sheer quantity of data contained in each data set says Fujimoto--but it is important because quantitative measurements can be used to track disease progression and help establish correlations between the severity of vision loss and changes in the architecture of the eye.
Researchers say this could provide a faster and more efficient way for drug makers to develop and evaluate new treatments in clinical trials. No treatment currently exists for dry AMD, and treatments for the wet form--including lasers that burn the blood vessels and drugs that inhibit the growth of new vessels--can only slow, not stop, vision loss.
Fujimoto's research takes advantage of ISP, an initiative undertaken by OSA in partnership with the National Library of Medicine, part of the National Institutes of Health, and with the support of the United States Air Force Office of Scientific Research. This initiative allows scientists to expand upon traditional research results in journal articles by providing software for interactively viewing underlying source data and to objectively compare the performance of different technologies. This data may be related to medical images, such as those taken with X-rays, MRIs, CT scans and ultrasounds, or it may be created in research involving oil and gas exploration, climatology, pollution monitoring and many other fields. Specifically in this instance, viewers are able to look at the actual OCT scans from the study patients as they read the paper. The software was developed in conjunction with Kitware, Inc.
More information:
See the paper, "Three-dimensional ultrahigh resolution optical coherence tomography imaging of age-related macular degeneration," Yueli Chen et al, in Optics Express.
And, find further details on ISP.
Posted by Barbara G. Goode, [email protected], for Laser Focus World.