Conventional retinal imaging includes the use of a fundus camera that limits the visual field to approximately 30 to 50 degrees of the retina in a single capture. However, an enhanced retinal imaging technology, ultra-widefield imaging (UWFI), can visualize up to a 200-degree retinal field in a single image, which translates to nearly 83 percent of the total retinal surface.
Advanced UWFI systems such as the Optos 200Tx™ not only generate fundus images but are also used to provide high-resolution ultra-widefield fluorescein angiograms, particularly important for imaging retinal vascular diseases and inflammatory eye disorders. In addition, ultra-widefield fundus autofluorescence is being used to better characterize diseases impacting the retinal pigment epithelium not only in the macula but also the periphery, such as degenerative retinal diseases.
Assessing Disease Burden
“Ultra-widefield imaging gives us a much better idea of the entire scope of retinal disease burden in diabetes and retinal vascular occlusive disease,” says Cole Eye Institute vitreoretinal surgeon Justis P. Ehlers, MD. For example, it can detect neovascularization that is present in a diabetic patient that may not be visualized with standard angiography. Because UWFI provides an overview of the entire retinal landscape in more detail rather than just a focused 30-degree field with survey photos, physicians may be able to better characterize the severity of the diseases that they are managing.
Cole Eye Institute ophthalmologists are seeking to understand how UWFI can clarify how to best manage patients based on the degree of ischemic burden. While the treatment repercussions of UWFI are not known for all retinal disorders, researchers are producing early data to learn more about the best uses for UWFI in clinical diagnosis and management.
Titrating Therapy in Ocular Inflammatory Diseases
To improve the diagnosis and measurement of ocular inflammatory activity, our ophthalmologists use UWFI, particularly fluorescein angiography. “In our patients with inflammatory diseases, we are able to detect areas of inflammation or areas of activity that were poorly recognized on traditional angiography,” says Sunil Srivastava, MD, retinal surgeon and uveitis specialist at Cole Eye Institute, referring to a study conducted at Cleveland Clinic. He says, “We use ultra-widefield angiography on the vast majority of, if not all, patients with inflammatory eye disease because we get a much better assessment of what is going on with these patients.”
Most anti-inflammatory medications have varying levels of toxicity. “For this reason I monitor all of my patients with retinal inflammatory diseases who are taking these drugs with UWF angiography,” Dr. Srivastava adds. “It allows me to better titrate the dosing based on the presence of inflammatory activity.”
UWFI is especially informative in patients with retinal vasculitis, Cole Eye Institute ophthalmologists have determined. They have particularly well-characterized one disease, Susac’s syndrome, using UWFI. At the International Susac syndrome Consultation Clinic at Cleveland Clinic, one of the largest clinics in the world for assessing those with the disease, ophthalmologists have learned that UWF angiography is the best way to determine if the disease is active in the eye. Says Dr. Srivastava, “Ultra-widefield imaging makes a huge difference for these patients because it helps us decide when to intervene and treat in order to prevent vision loss.”
Inherited Retinal Disease
UWFI with fundus autofluorescence provides a better perspective on inherited retinal diseases. “We do ultra-widefield fundus autofluorescence on all our patients with retinal dystrophies,” explains Elias Traboulsi, MD, Head of the Department of Pediatric Ophthalmology and Director of the Center for Genetic Eye Diseases at Cole Eye Institute. While the list of retinal dystrophies is long, among the most common are Stargardt diseases, retinitis pigmentosa, Usher syndrome and choroideremia. “Many of these diseases have very characteristic patterns of abnormality that we can now recognize because we can see nearly the entire retina in just one image,” he adds. No longer is it necessary to spend hours piecing together a collage of retinal images that even when complete do not capture the entire periphery.
Distinguishing between patterns of abnormalities helps ophthalmologists with differential diagnosis, often between a number of very rare inherited diseases. We are hopeful UWFI will also assist in understanding the progression of these rare disorders as in well as comparing the effects of treatment. “I think it is also going to be very helpful for us in following patients who will eventually become eligible for gene therapy,” Dr. Traboulsi adds. “As that becomes available, we have to have additional ways of monitoring these patients.”