As recommended by the Clinical Director at Heidelberg Engineering, Christopher Mody
Classification of AMD
Classification of AMD falls into two distinct categories: neovascular AMD (nAMD), sometimes referred to as exudative AMD (eAMD) or wet AMD, and atrophic AMD (aAMD) or dry AMD, with the advanced form of the disease being geographic atrophy (GA). These disease entities require slightly different approaches to imaging protocol.
Imaging Protocols
Neovascular AMD
A diagnosis of neovascular AMD requires confirmation of exudation in the presence of fundus features consistent with age-related change.
A protocol for investigating nAMD would include fundus documentation using a combination of infrared reflectance, MultiColor (SPECTRALIS) reflectance, blue laser autofluorescence (BluePeak Module) and structural assessment of retinal architecture using optical coherence tomography (OCT).
OCT protocol should utilize highly averaged line scans, intersecting the fovea in a horizontal and vertical orientation, in combination with a macula volume scan.
OCT and fundus documentation provides high-resolution, cross-sectional images of the retina to identify fluid, retinal thickness and choroidal neovascularization (CNV)—the mainstay of follow-up assessment and therapeutic monitoring. The use of AI in fluid segmentation can add an enhanced level of precision to therapeutic monitoring.
Atrophic AMD
Imaging of patients with early or intermediate aAMD should include fundus documentation with MultiColor (SPECTRALIS) reflectance imaging.
BluePeak Module autofluorescence provides a map of retinal pigment epithelium (RPE) photoreceptor physiology. Regions of hypo-autofluorescence correspond with regions of RPE/photoreceptor atrophy permitting measurement of areas of complete retinal pigment epithelium and outer retinal atrophy (cRORA) or geographic atrophy (GA) to assess progress or response to therapy. Peri-lesional autofluorescence can be correlated with areas of GA lesion progression and growth. Autofluorescence imaging has the benefit of being able to identify masqueraders of GA. There are multiple causes of retinal and RPE atrophy; these must be excluded prior to initiating anti-complement therapy.
OCT assessment of retinal structure is key to the accurate diagnosis of cRORA/GA. The disease is classified, and its severity is indicated by evaluating OCT B-scans and en-face OCT features.
Enhancing Imaging Quality and Patient Engagement
The SPECTRALIS combines confocal optics, SD-OCT, active eye tracking, image averaging and noise reduction to deliver astonishing images and precise follow-up. Optimizing imaging technologies for each application can support earlier diagnosis, individualized patient care and treatment at the right time.
To support patient education on disease severity in GA therapy, using BluePeak autofluorescence in combination with RegionFinder software is effective. The concept of “black is bad” on autofluorescence images is easy for patients and carers to understand, and using the progression movie mode in RegionFinder demonstrates lesion growth and disease progression in an easy-to-understand way.
Editor’s Note: A version of this article was first published in PIE Magazine Issue 32.
