Novel grid combined with peripheral distortion correction for ultra-widefield image grading of age-related macular degeneration

Abstract

Purpose: Eyes with age-related macular degeneration (AMD) often harbor pathological changes in the retinal periphery and perimacular region. These extramacular changes have not been well classified, but may be phenotypically and functionally relevant. The purpose of this study was to demonstrate a novel grid to systematically study peripheral retinal abnormalities in AMD using geometric distortion-corrected ultra-widefield (UWF) imaging.

Methods: This is a cross-sectional observational case series. Consecutive patients with AMD without any other coexisting vitreoretinal disease and control patients over age 50 without AMD or any other vitreoretinal disease were imaged using Optos 200 Tx. Captured 200° UWF images were corrected for peripheral geometric distortion using Optos transformation software. A newly developed grid to study perimacular and peripheral abnormalities in AMD was then projected onto the images.

Results: Peripheral and perimacular changes such as drusen, retinal pigment epithelium changes and atrophy were found in patients with AMD. The presented grid in conjunction with geometric distortion-corrected UWF images allowed for systematic study of these peripheral changes in AMD.

Conclusion: We present a novel grid to study peripheral and posterior pole changes in AMD. The grid is unique in that it adds a perimacular zone, which may be important in characterizing certain phenotypes in AMD. Our UWF images were corrected for geometric peripheral distortion to accurately reflect the anatomical dimensions of the retina. This grid offers a reliable and reproducible foundation for the exploration of peripheral retinal pathology associated with AMD.

Keywords: autofluorescence; drusen; grid; macular degeneration; periphery; retinal pigment epithelium changes; ultra-widefield.

Figure 1

Gaze positions to optimally capture entire fundus in ultra-widefield imaging. Images were routinely captured in primary gaze, upgaze and downgaze. While primary gaze images reflect the temporal and nasal periphery reasonably well, it is necessary to capture images in upgaze and downgaze to better show the superior and inferior periphery as demonstrated in this ultra-widefield autofluorescence image sequence of a left eye.

Figure 2

Novel grid to systematically grade peripheral abnormalities in age-related macular degeneration. The grid consists of three concentric circles and two lines. The central circle surrounds the macula area. The middle circle surrounds the perimacular area (^*). The largest circle separates the mid periphery (+) from the far periphery (=). A vertical line through the fovea separates temporal from nasal quadrants. A horizontal line through the fovea separates superior from inferior quadrants.

Figure 3

Patient with age-related macular degeneration and widespread perimacular and peripheral abnormalities. Ultra-widefield pseudocolor images of the right eye demonstrate foveal retinal pigment epithelium (RPE) changes along with macular drusen in all quadrants. There are extensive drusenoid changes in the perimacular area in the temporal quadrants, as well as mid-peripheral and far-peripheral drusen and RPE changes (A–C). Analogous to this, ultra-widefield autofluorescence shows mixed hyper/hypoautofluorescence in the macula and hyperautofluorescence in the perimacula. The mid- and far periphery show partially mottled hyperautofluorescence (D–F). Upgaze (A and D); primary gaze (B and E), downgaze (C and F).

Figure 4

Patient with age-related macular degeneration and peripheral abnormalities. Ultra-widefield pseudocolor images of the left eye demonstrate juxtafoveal geographic atrophy and macular drusen, partially extending into the perimacular region. There are a few drusen, mostly in the nasal far periphery, but also inferior along the border of mid- and far periphery (A–C). Corresponding autofluorescence images demonstrate brisk hypoautofluorescence juxtafoveally with adjacent hyperautofluorescence. There is hyperautofluorescence, which extends into the temporal perimacular as well as speckled hyperautofluorescence, mostly nasally and inferiorly (D–F). Upgaze (A and D); primary gaze (B and E), downgaze (C and F).

Figure 5

Patient without age-related macular degeneration and nonspecific peripheral retinal changes. Ultra-widefield pseudocolor images of the right eye demonstrate normal macula and a few nonspecific changes in the peripheral retina (A–C). Autofluorescence imaging demonstrates focal retinal pigment epithelium atrophy in the superonasal mid periphery as well as patchy hyperautofluorescence inferotemporally along the border of mid- and far periphery (D–F). Upgaze (A and D); primary gaze (B and E), downgaze (C and F).