Nascent geographic atrophy observed on early OCT may reliably indicate GA progression
KOLOA, Hawaii — Nascent geographic atrophy may be a reliable indicator for progression to geographic atrophy, which could help with age-related macular degeneration interventions when detected early through OCT.
At Retina 2023, Robyn Guymer, MD, said that signs of geographic atrophy (GA) can be found earlier when using OCT compared with color fundus imaging and fundus autofluorescence.
“We wanted to find out what the signs were on the OCT that preceded the development of atrophy,” Guymer said.
To investigate the efficacy of detecting early GA biomarkers on OCT, Guymer and colleagues assessed 181 participants with drusen greater than 125 µm in at least one eye and followed up with them every 3 months for up to 30 months. Among the participants, 20 areas of 16 eyes developed drusen-associated atrophy, which allowed the researchers to look at possible features that may have predicted the progression.
According to Guymer, the two features observed through OCT included the subsidence of the outer plexiform layer and inner nuclear layer and/or the development of a hyporeflective wedge-shaped band in the limits of the outer plexiform layer.
“We thought that this nascent GA could be an early surrogate endpoint that you perhaps could use in trials if you wanted to start earlier,” Guymer said. “So, for nascent geographic atrophy, one or the other is enough.”
While a greater percentage of eyes had incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) compared with nascent GA, nascent GA was found to be a significant predictor for GA progression, with 56% of eyes progressing to GA at 30 months; 10% of eyes with iRORA progressed to GA at 30 months.
Guymer said that incorporating OCT scans that look for signs of nascent GA and iRORA can help specialists identify cohorts of patients at risk for GA progression, allowing for early AMD intervention.
“I think these findings give us guidance on when and how useful nascent GA and iRORA are as risk factors for geographic atrophy” Guymer said. “iRORA is a significant risk factor. ... Nascent GA, with that subsidence and wedge, seems to be much more highly predictive of those eyes that go on to geographic atrophy. ... If you include nascent GA as an outcome measure, it’s going to substantially improve the feasibility of evaluating new interventions.”
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Guymer R. Early OCT signs of atrophy in age-related macular degeneration. Presented at: Retina 2023; Jan. 15-20, 2023; Koloa, Hawaii.