In patients with Asian ethnicity who have neovascular age-related macular degeneration (nAMD), the 5-year incidence of fellow eye involvement is lower than it is for patients with White ethnicity, according to findings published in Retina. Researchers speculate that a higher proportion of the polypoidal choroidal vasculopathy (PCV) subtype of nAMD in patients of Asian ethnicity is behind the finding.
Researchers conducted a prospective cohort study which evaluated fellow eyes in 488 patients of Asian ethnicity with nAMD and PCV for exudation and compared the 5-year incidence between nAMD and PCV. They calculated the incidence of fellow eye involvement in patients with White ethnicities — approximately 19-30% in 5 years, and an annual incidence of 10% — from a combination of large population studies, long term follow-up of previous clinical trials, and real world reports.
The study shows the 5-year incidence in fellow eyes of the study population is approximately 16.2% (95% CI 12.0-20.2). When compared with nAMD in the first eye, patients with the PCV subtype of nAMD experience lower fellow eye progression (9.8%; [95% CI 5.1-14.3, vs 22.9% [95% CI 15.8-29.3]). Drusen, shallow irregular retinal pigment epithelium elevation (SIRE), and pigment epithelial detachment (PED) are all associated with greater progression.
Specific PED subtypes (multilobular and sharp peaked) and subretinal drusenoid deposits are also associated with progression, according to the researchers. Before exudation, PED, SIRE, and new subretinal hyperreflective material occurred at 10.4±4.2, 11.1±6.0, and 6.9±4.3 months, respectively.
To assess the risk of incident fellow eye exudation, researchers explain that imaging modalities such as optical coherence tomography (OCT), paired with a clinical examination, are imperative for patients of Asian ethnicity with unilateral AMD. As such, certain clinical signs may help to inform clinicians about the risk of exudation of the fellow eye.
“Increasing size of PED and SIRE, coupled with the presence of multilobular or sharp peaked PED, are warning signs of impending exudation and such patients should be followed up more closely to prevent irreversible vision loss,” the study authors explain.
Study limitations include its lack of OCT-angiography, which would reveal the presence of quiescent macular neovascularization.
Teo KYC, Vyas C, Sun C, Cheong KX, Chakravarthy U. Five-year incidence of fellow eye neovascular involvement in age-related macular degeneration and polypoidal choroidal vasculopathy in an Asian population. Retina. Published online November 2, 2022. doi:10.1097/IAE.000000000000366