ANAHEIM, California — Better characterization and increasing understanding of geographic atrophy are giving researchers hope that there will soon be new therapies for the disease.
"We've got a disease without a treatment," said Mark Dunbar, OD, from the Bascom Palmer Eye Institute in Miami. But we "are trying to generate awareness that there is hopefully a treatment coming down the pipe."
Dr Dunbar presented a review of the literature on geographic atrophy here at the American Academy of Optometry 2016.
The disease — the advanced stage of age-related macular degeneration — affects more than 5 million people around the world, he reported.
The prevalence of geographic atrophy closely parallels that of neovascular — or wet — age-related macular degeneration, rising sharply in people 65 years and older. "Geographic atrophy might be more common than we thought it was," he explained.
Outcomes for patients with neovascular age-related macular degeneration improved dramatically after the advent of anti-vascular endothelial growth-factor (VEGF) therapy. "It's been a breakthrough having a treatment for the wet form of the disease," said Dr Dunbar.
Researchers are now gaining a better understanding of geographic atrophy and hope for similar progress.
Already, coding for the condition was changed in the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) to allow for the better collection of data, Dr Dunbar told Medscape Medical News.
Previous ICD codes did not specifically code for geographic atrophy, they only distinguished between exudative and nonexudative AMD, he explained. The new codes will allow better tracking of disease progression in electronic health records.
Table 1. ICD-10 Classification
| Code | Classification | Defining Characteristics |
| H35.31X0 | Non-exudative (dry) AMD | |
| H35.31X1 | Early AMD | Combination of multiple small drusen (≤63 µm), few intermediate drusen (>63–125 µm), few intermediate drusen (≥63 to ≤124 µm), or retinal pigment epithelium abnormalities |
| H35.31X2 | Intermediate AMD | Extensive intermediate drusen (>63 µm to ≤124 µm) or at least 1 large drusen (>125 µm) |
| H35.31X3 | Advanced atrophic AMD without subfoveal involvement | Geographic atrophy not involving the center of the fovea |
| H35.31X4 | Advanced atrophic AMD with subfoveal involvement | Geographic atrophy involving the center of the fovea |
And the Beckman Initiative for Macular Research, now the Stephen J. Ryan Initiative for Macular Research, has developed a new classification for age-related macular degeneration.
Table 2. Beckman Initiative for Macular Research Classification for Age-Related Macular Degeneration
| Classification | Defining Characteristics |
| Normal aging | No or a few drupelets; drusen <63 µm |
| Early AMD | Drusen 63 µm–125 µm |
| Intermediate AMD | Drusen >125 µm |
| Advanced AMD | Geographic atrophy or neovascular AMD |
Multimodal geographic atrophy imaging technologies can help monitor progression of the disease, said Dr Dunbar.
Spectral domain optical coherence tomography can define the boundaries of the geographic atrophy and reveal intraretinal changes, including the degradation of individual layers, the loss of retinal pigment epithelium, and the change in lesion size, he explained.
And fundus autofluorescence offers better delineation of lesion boundaries than fundus photos. The enhanced signal at lesion boundaries might predict areas of lesion progression.
"We'll have a better sense of what the incidence is and be able to follow these patients more closely," Dr Dunbar said.
At the same time, researchers have begun to tease apart the complex of genetic and environmental factors involved in age-related macular degeneration, including 19 different genes and oxidative stress, that result in immune system dysregulation and attacks on the retina.
Investigators have zeroed in on the alternative complement pathway of the immune system as a key link in the chain of events that leads to a damaged macula.
"There are a number of treatments that might become available," Dr Dunbar reported. He listed two agents in phase 2 trials — GLG561 (Novartis) and APL-2 (Apellis Pharmaceuticals); one in phase 2/3 trials — avacincaptad pegol sodium (Zimura, Ophthatech); and one in phase 3 trials — lampalizumab (Genentech/Roche). These drugs inhibit various components of the alternative complement pathway.
These findings herald a big change in the approach that optometrists will be taking to geographic atrophy, said Andrew Mick, an associate clinical professor of optometry at the UC Berkeley School of Optometry in California.
"For an entire generation, we have essentially screened for this transformation from dry to wet," he told Medscape Medical News.
Optometrists of the future will not only classify patients by the new ICD-10 codes, but will also, perhaps, identify those who can benefit from treatment, Dr Mick said.
Dr Dunbar reports that he is on the advisory board of Genentech. Dr Mick has disclosed no relevant financial relationships.
American Academy of Optometry (AAOpt) 2016: Abstract 165159. Presented November 10, 2016.
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Cite this: Changes Coming in the Management of Geographic Atrophy - Medscape - Nov 13, 2016.
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