Sponsored by Optos Ophthalmology

Expanding Horizons in Retinal Imaging

Benefits of ultra-widefield imaging

David Boyer, MD

Ultra-widefield retinal imaging allows us to simultaneously view more than 80% — or 200º — of the retina for diagnosing, analyzing, documenting and monitoring pathology in the periphery. Potential benefits include the ability to:
• identify pathologic changes in the retinal periphery that may be present earlier than changes closer to the macula
• determine which patients may be at risk for advancing disease
• provide more selective treatment that may allow for reduced frequency of anti-VEGF injections and reduced chronicity of many of the posterior-segment diseases we treat.

The technology allowing for ultra-widefield retinal imaging is available in an entire line of devices from Optos, including the Optos 200Tx. The 200Tx is the first instrument that provides visualization of ultra-widefield autofluorescence changes in the retinal pigment epithelium (RPE). It also provides multiple wavelength imaging, including options for color, red-free and fluorescein angiography. Its expansive views of the retina and resulting optomaps are obtained in a single capture, even through small pupils. The 200Tx contains key enhancements, including those that improve the clarity of both the peripheral and macular images.

Below, Drs. Szilard Kiss and Ivan Suner present highlights of the presentations they gave in Orlando, which were based on their experience with ultra-widefield imaging and how it is changing the way they practice.

Improving Disease Classification and Monitoring with the Optos 200Tx

Szilard Kiss, MD

When we first began using ultra-widefield imaging, there was definitely a “wow” factor. It was clear how much more of the retina we were able to see beyond our 7-standard fields and traditional fluorescein angiography. What we wanted to explore, however, was the “so what” factor. What difference might the expanded view make?

Toward that end, we looked retrospectively at 250 eyes of patients with diabetes who were imaged with the Optos 200Tx in our practice.¹ We quantified the areas of pathology that we were able to see on idealized 7-standard fields vs. with ultrawidefield angiography. Interestingly, we saw a hotbed of retinopathy just outside the arcades. Also, in the ultra-widefield views, we saw almost four times the area of nonperfusion/schemia and almost two times the area of neovascularization. As far as the clinical relevance of that, it altered our classification of the patients' disease. For example, approximately 10% of our patients had pathology outside the 7-standard fields, so they would have been classified as having nonproliferative disease. In contrast, the ultra-widefield view put them in the category of proliferative diabetic retinopathy.

We also evaluated sickle cell retinopathy using various imaging methods.² In all but one of the 12 eyes, the ultra-widefield images detected peripheral vascular changes, such as arterio-venous anastomoses, areas of ischemia and areas where the blood vessels were starting to go away, that were missed on 7-standard field photographs. We were able to think about how that might change the classification of retinopathy in these patients and how we could perhaps identify high-risk characteristics for proliferative sickle cell retinopathy.

We have many other examples from our practice of the value of imaging the retinal periphery. Our work, and similar work from others, suggests that the information we can obtain could influence the follow-up care and treatments we choose for patients. What we take away from our experience so far with the Optos 200Tx is that it allows us to see more pathology, classify disease more accurately and perhaps adjust our treatment algorithms accordingly. Furthermore, we're not losing anything by imaging the periphery, because we can still see the relevant pathology in the posterior pole.

References

1. Wessel MW, Aaker G, Parlitsis GJ, Cho M, D'Amico DJ, Kiss S. PO504: Ultrawidefield angiography significantly improves detection and classification of diabetic retinopathy. Presented Oct. 18, 2010, American Academy of Ophthalmology annual meeting, Chicago.
2. Cho M, Kiss S. Detection and monitoring of sickle cell retinopathy using ultra widefield color photography and fluorescein angiography. Retina 2011;31(4):738-747.

Exploring Targeted Treatment Based on the Peripheral View

Ivan J. Suner, MD

An interesting observation from the CRUISE and BRAVO studies of anti-VEGF therapy for retinal vein occlusion was that many patients do well with just a few injections, while some experience recurrence and require more. This leads us to think about the underlying pathology. Is the main driver actually a peripheral ischemic process that results in excessive VEGF release and then macular edema? If so, it is reasonable to explore if targeting peripheral scatter laser specifically to areas of nonperfusion would be an effective treatment.

This strategy has been successful for patients in our practice, including a 68-year-old Hispanic man we treated recently. He is hypertensive and had a branch retinal vein occlusion with associated macular edema in the right eye for about 16 months. Previous treatment included macular laser, several rounds of bevacizumab (Avastin, Genentech) and several rounds of ranibizumab (Lucentis, Genentech) injections. He had grown tired of repeated injections and was referred to us to determine if we could do anything else for him.

Imaging with the Optos 200Tx showed some vascular abnormalities and a sclerotic vessel, but otherwise, nothing remarkable in the macula. OCT showed macular thickening. With ultra-widefield angiography, we could see nonperfusion in the retinal periphery, which would have been missed with conventional angiography.

For this patient, we avoided macular therapy. Instead, we gave him one ranibizumab injection and performed ultra-widefield angiography-guided laser therapy to the area of peripheral nonperfusion. By 1 month, macular thickening was reduced and vision had improved. At 6 months, OCT showed some residual intraretinal thickening, but otherwise very normal-looking macular contour. Our ultra-widefield imaging showed improved macular vessel architecture and much-reduced leakage compared with the original angiogram.

We're more formally testing the durability of this treatment approach with a pilot study called Revolution (REtinal Vein OccLUsion Treatment With Scatter Laser Guided by UWFA in combiNAtion With Ranibizumab Study). We hope it will shed light on how marrying this new imaging technology with expanding options in pharmacologic and laser therapy can help us refine our treatment algorithms and improve patient outcomes. ■