Optical Coherence Tomography Angiography of Asymptomatic Neovascularization in Intermediate Age-Related Macular Degeneration

Abstract

Purpose: To determine whether angiography with swept-source (SS) optical coherence tomography (OCT) identifies subclinical type 1 neovascularization in asymptomatic eyes with intermediate age-related macular degeneration (iAMD).

Design: Prospective, observational, consecutive case series.

Participants: Patients with asymptomatic iAMD in one eye and neovascular age-related macular degeneration (AMD) in their fellow eye.

Methods: The patients underwent SS OCT angiography (OCTA), fluorescein angiography (FA), and indocyanine green angiography (ICGA), and the images from these 3 angiographic techniques were compared.

Main outcome measures: Identification of subclinical type 1 neovascularization with SS OCTA in asymptomatic eyes with iAMD.

Results: Eleven consecutive patients with iAMD in one eye and neovascular AMD in their fellow eye were imaged with FA, ICGA, and SS OCTA between August 2014 and September 2015. Clinical examination of the 11 eyes revealed drusen and pigmentary abnormalities in the central macula and no evidence of macular fluid on routine OCT imaging. Ten of the 11 eyes had no evidence of leakage on FA and 1 eye had questionable fluorescein leakage. Indocyanine green angiography revealed the presence of central macular plaques in 3 of the 11 asymptomatic eyes with iAMD, and SS OCTA revealed unambiguous type 1 neovascularization corresponding to the plaques in all 3 eyes. Optical coherence tomography angiography did not identify neovascularization in the remaining 8 eyes.

Conclusions: Swept-source OCTA identified type 1 neovascularization corresponding to ICGA plaques in asymptomatic eyes with iAMD. The ability of OCTA to provide noninvasive, fast, detailed, depth-resolved identification of nonexudative neovascular lesions in eyes with iAMD suggests the need for a new classification system that distinguishes between neovascular and nonneovascular iAMD.

Figure 1

Case #1: Color fundus, autofluorescence (AF), fluorescein, and indocyanine green (ICG) angiography imaging of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Color fundus imaging of drusen, pigmentary abnormalities, and reticular pseudodrusen (RPD). (B) AF imaging of RPD. (C, D) Early and late frames from a fluorescein angiogram showing some early focal hyperfluorescence but no obvious late leakage and RPD surrounding the central macula. (E, F) Early and late frames from an ICGA showing a central plaque in the late frames and RPD surrounding the central macula.

Figure 2

Case #1: Swept source optical coherence tomography microangiography (SS-OMAG) of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Standard OCT B-scan through the fovea showing elevations of the RPE consistent with typical drusen, but no evidence of macular fluid. (B) Standard OCT B-scan through the fovea with color-coded flow represented as red and green for the retinal microvasculature, pink for flow under the RPE and within the inner CC, and green for flow in the remainder of the choroid. Note the pink coloration under the RPE elevations that were thought to be a typical drusen on the routine OCT B-scan. (C) Magnified area of the plaque seen on late ICGA corresponding to the same area scanned by SS-OMAG. (D–F) SS-OMAG en face images of a slab between the outer retinal layer, which was the bottom boundary of the outer plexiform layer, to the choriocapillaris, which was about 8 um beneath Bruch’s membrane. (D) SS-OMAG en face image showing a multilobular neovascular complex best observed using a slab from outer retinal layer (ORL), just the RPE, to the inner portion choriocapillaris (CC). (E) The same en face image showed in panel D following removal of projection artifacts. (F) Composite, color-coded en face SS-OMAG flow image encompassing the outer retinal layer and the choroid revealing the multilobular type 1 neovascularization in pink.

Figure 3

Case #2: Color fundus, autofluorescence (AF), fluorescein, and indocyanine green (ICG) angiography imaging of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Color fundus imaging of drusen, pigmentary abnormalities, and reticular pseudodrusen (RPD). (B) AF imaging of RPD. (C and D) Early and late frames from a fluorescein angiogram showing some early focal hyperfluorescence but no obvious late leakage and reticular pseudodrusen (RPD) surrounding the central macula. (E and F) Early and late frames from an ICG angiogram showing a central plaque in the late frames and RPD surrounding the central macula.

Figure 4

Case #2: Swept source optical coherence tomography microangiography (SS-OMAG) of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Standard OCT B-scan through the fovea showing elevations of the RPE consistent with typical drusen, but no evidence of macular fluid. (B) Standard OCT B-scan through the fovea with color-coded flow represented as red and green for the retinal microvasculature, pink for flow under the RPE and within the inner CC, and green for flow in the remainder of the choroid. Note the pink coloration under the RPE elevations that were thought to be a typical, confluent drusen on the routine OCT B-scan. (C) Magnified area of the plaque seen on late ICGA corresponding to the same area scanned by SS-OMAG. (D–F) SS-OMAG en face images of a slab between the outer retinal layer, which was the bottom boundary of the outer plexiform layer, to the choriocapillaris, which was about 8 um beneath Bruch’s membrane. (D) SS-OMAG en face image showing a circular neovasculature complex best observed using a slab from outer retinal layer (ORL), just the RPE, to the inner portion choriocapillaris (CC). (E) The same en face image showed in panel D following removal of projection artifacts. (F) Composite, color-coded en face SS-OMAG flow image encompassing the outer retinal layer and the choroid revealing the circular type 1 neovascularization in pink.

Figure 5

Case #3: Color fundus, autofluorescence (AF), fluorescein, and indocyanine green (ICG) angiography imaging of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Color fundus imaging of drusen and pigmentary abnormalities. (B) AF imaging of reticular pseudodrusen (RPD) more evident around the superior arcade. (C and D) Early and late frames from a fluorescein angiogram showing some early stippled hyperfluorescence and subtle late leakage consistent with type 1 neovascularization. (E and F) Early and late frames from an ICG angiogram showing a central multilobular plaque in the late frames.

Figure 6

Case #3: Swept source optical coherence tomography microangiography (SS-OMAG) of an asymptomatic eye from a patient with exudative age-related macular degeneration in their fellow eye. (A) Standard OCT B-scan through the fovea showing elevations of the RPE consistent with typical, confluent drusen, but no evidence of macular fluid. (B) Standard OCT B-scan through the fovea with color-coded flow represented as red and green for the retinal microvasculature, pink for flow under the RPE and within the inner CC, and green for flow in the remainder of the choroid. Note the pink coloration under the RPE elevations that were thought to be a typical drusen on the routine OCT B-scan. (C) Magnified area of the plaque seen on late ICGA corresponding to the same area scanned by SS-OMAG. (D–F) SS-OMAG en face images of a slab between the outer retinal layer, which was the bottom boundary of the outer plexiform layer, to the choriocapillaris, which was about 8 um beneath Bruch’s membrane. (D) SS-OMAG en face image showing a multilobular neovasculature complex best observed using a slab from outer retinal layer (ORL), just the RPE, to the inner portion choriocapillaris (CC). (E) The same en face image showed in panel D following removal of projection artifacts. (F) Composite, color-coded en face SS-OMAG flow image encompassing the outer retinal layer and the choroid revealing the circular type 1 neovascularization in pink.