Lauren Kiryakoza, MD
Bascom Palmer Eye Institute
On day one of retina subspecialty day, Dr. Philip J. Rosenfeld delivered the distinguished Charles L. Schepens lecture. Dr. Stephen McLeod introduced Dr. Rosenfeld and acknowledged his remarkable career in ophthalmology, marked by numerous awards including the AAO Senior Achievement and Secretariat award. Dr. Rosenfeld then began by recognizing the trailblazing retina career of Dr. Charles Schepens, including his role in founding The Retina Society and his positive influence on Dr. Rosenfeld during his time as an ophthalmology resident at the Massachusetts Eye and Ear Infirmary. He thanked his family and his award “co-recipients”, a large group of co-researchers and staff at Bascom Palmer Eye Institute, the University of Washington Seattle, researchers across the globe in Shanghai, China, and many more.
Dr. Rosenfeld’s lecture was entitled “Rediscovering AMD with SS-OCT Imaging”. The talk began, first, by looking back. At AAO 2004, he introduced the use of time-domain OCT to monitor neovascular-AMD treatment response, as demonstrated by the “Prospective OCT imaging of patients with neovascular AMD treated with intraocular ranibizumab” study (PrONTO). In 2007, spectral-domain OCT was introduced with raster scanning patterns and the thickness MAP. In 2016, the revolutionary swept source – OCT (SS – OCT), with its faster scanning speeds, longer wavelength, denser penetration into the choroid, and wider fields of view, was introduced.
The power of SS-OCT angiography (SS-OCTA) in neovascular retinal diseases lies in the optical microangiography algorithm that provides the angiogram images. These images can be segmented by specific boundaries to view precise, desired slabs of the retina, such as the outer retina or the choriocapillaris. The power of SS – OCTA is not limited to neovascular-AMD, as Dr. Rosenfeld explained. SS-OCTA, identifies, for example, the polyps of polypoidal choroidal vasculopathy on the structural B-scan and can precisely display the polyp and associated type 1 branching vascular network using the segmentation tool.
The talk then mentioned the utility of SS-OCTA in studying the natural history of subclinical macular neovascularization (MNV) in eyes with intermediate non-exudative AMD and geographic atrophy (GA). In a study by Dr. De Oliveira Dias, Dr. Rosenfeld, and others, SS-OCTA identified subclinical MNV in 14.4% of eyes at first imaging. At 12 months, cumulative incidence of exudation in eyes with subclinical MNV at first imaging was 21.1% compared to 3.6% in eyes without subclinical MNV.
In the final portion of the lecture, Dr. Rosenfeld emphasized the power of SS-OCTA slab segmentation in identifying potential OCT biomarkers for progression of non-exudative AMD as well. One OCT biomarker is the choriocapillaris hyper- transmission defect, appreciated in the en-face sub-RPE segmentation slab as a “bright spot”. When lesions of 250 m or larger appeared, there was an increased risk of progression to GA in one study by Dr. Rosenfeld’s team. Another potential SS-OCT biomarker of non-exudative AMD progression is the choroidal hypo-transmission defect, best seen as a “black spot” on the sub-RPE segmentation slab. Areas of abnormal pigment accumulation block light transmission to the choroid, resulting in the black spot seen on imaging. These lesions are thought to be associated with disease progression. Other OCT biomarkers he mentioned included choriocapillaris flow deficits, basal laminar deposits, and photoreceptor thinning. He noted that 62% of GA growth could be explained by choriocapillaris flow deficits, basal laminar deposits, and photoreceptor thinning in a multiple regression model. To close the talk, he left the audience wondering what explained the remaining 38% of GA growth and mentioned ideas for new SS-OCTA-based clinical trials. Dr. Rosenfeld’s engaging presentation and outstanding contributions to the field of retina kicked off an exciting first day of AAO.