Thursday, January 26, 2012

AMD Update 16: Visualization of Drusen and RPE With New Software Application for Zeiss HD-OCT: A New Aid for Assessing Both Dry and Wet AMD

As noted below, by both Drs. Rosenfeld and Puliafito, this new diagnostic tool will play an important role in assessing and speeding the development of new treatments for both dry and wet AMD that are being researched and brought to the market.

In an announcement on January 20th, Carl Zeiss Meditec said that it had added new dry age-related macular degeneration (Dry AMD) and new glaucoma diagnostic tools for its Cirrus HD-OCT (High Definition Optical Coherence Tomography), and the new software, version 6.0, had received clearance from the US Food and Drug Administration (FDA).

Zeiss Meditec Cirrus HD-OCT
"Designed to help ophthalmologists manage the growing number of patients with serious eye diseases, the new Cirrus application package offers a more comprehensive approach to disease management, delivering more thorough and more meaningful clinical analysis within the retina and glaucoma workplaces", said Dr. Ludwin Monz, President and CEO of Carl Zeiss Meditec AG.

The new Cirrus HD-OCT retina application provides Advanced Retinal Pigment Epithelium (RPE) Analysis, which enables clinicians to objectively monitor changes associated with dry AMD. The application tracks change in RPE elevation area and volume often associated with drusen. It also identifies and measures the area of transparent regions in the RPE that can develop with geographic atrophy. Unlike blue light fundus autofluorescence (FAF), Cirrus measurements are not affected by macular pigment in the fovea and provide an objective assessment of geographic atrophy status as part of a standard OCT exam.

Further expanding Carl Zeiss Meditec's retina workplace, the Cirrus HD-OCT application package also includes Enhanced Depth Imaging (EDI), which allows for better visualization of deeper tissues, such as the choroid, enabling doctors to better understand the role of this anatomy in retinal disease.

A Look at the Retinal Layers Able to be Visualized

"The new integrated RPE Analysis software now offers clinicians the opportunity to objectively analyze all stages of AMD, especially the progression of dry AMD. Now one imaging technique, the Cirrus HD-OCT, can quantitate drusen and geographic atrophy, as well as choroidal neovascularization (CNV) and any elevation of the RPE associated with wet AMD," said Dr. Philip J. Rosenfeld, Professor of Ophthalmology at the Bascom Palmer Eye Institute and collaborator with Carl Zeiss Meditec in developing the techniques underlying the new applications. "Now we don't have to move patients between different instruments to visualize drusen, geographic atrophy, and CNV. These analyses will help clinicians stage and monitor disease progression today and will be critical to managing response to therapy as new treatments come to market."

As pointed out by Carmen Puliafito, MD, speaking at Retina 2012, held last week in Hawaii, “New algorithms to translate spectral domain optical coherence tomography images have begun to allow retinal specialists to measure drusen volume and area for the first time and may offer a better understanding of age-related macular degeneration. We now have some really objective tools that we can use to look at disease progression and then perhaps come to a better understanding of the pathophysiology of what exactly this disease is."

Fundus photography allows ophthalmologists to see drusen, but trying to count or measure it is nearly impossible, Dr. Puliafito said. These new methods will allow ophthalmologists to view the internal limiting membrane and the retinal pigment epithelium and where the retinal pigment epithelium should be, resulting in elevations that correspond to drusen, he said. This provides a major step forward in quantification.

"Drusen come, drusen go. And in their wake can be geographic atrophy, choroidal neovascularization or absolutely nothing," Dr. Puliafito said. "We now have some really objective tools to look at disease progression" to better understand AMD.

The new Cirrus HD-OCT application package also extends Carl Zeiss Meditec`s comprehensive suite of glaucoma diagnostic tools, adding new Ganglion Cell Analysis and Optic Nerve Head Progression Analysis. The Ganglion Cell Analysis evaluates the thickness of the combined ganglion cell and inner plexiform layers and compares the results to normative data. The new software package also expands Guided Progression Analysis (GPA) to automatically track progression of average cup-to-disc ratio and other optic nerve head parameters.

With these new clinical applications, Cirrus HD-OCT now spans the full spectrum of visualization and structural assessment in glaucoma: angle assessment, central corneal thickness measurement and analyses of retinal nerve fiber layer, ganglion cell layer and optic nerve head.

The new software package addresses a global market by adding user interfaces in Japanese, Chinese, Korean, German, French, Italian and Spanish to the original English interface. The software received its CE mark for distribution to major European markets in November, 2011.


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