Neurodegeneration and choroidal vascular features on OCT in the progression to advanced age-related macular degeneration.

Aim: To quantify and compare longitudinal thickness changes of the ganglion cell complex (GCC) and the choroid in patients with different patterns of age-related macular degeneration (AMD) progression.

Methods: Retrospective cohort analysis of anonymized data from participants aged 50y or more and diagnosed with early/intermediate AMD in at least one eye (with no evidence of advanced AMD). A total of 64 participants were included from the Instituto de Retina de Lisboa (IRL) study (IPL/2022/MetAllAMD_ESTeSL) and divided into 4 groups according to the Rotterdam classification for AMD. Spectral domain optical coherence tomography (SD-OCT) was used to assess and quantify GCC and choroid thickness at two time points (first visit vs last visit) with a minimum interval of 3y.

Results: In the GCC inner ring, a thinner thickness (P=0.001) was observed in the atrophic AMD group (51.3±21.4 µm) compared to the early AMD (84.3±11.5 µm), intermediate AMD (77.6±16.1 µm) and neovascular AMD (88.9±16.3 µm) groups. Choroidal thickness quantification showed a generalized reduction in the central circle (P=0.002) and inner ring (P=0.001). Slight reductions in retinal thickness were more accentuated in the inner ring in the atrophic AMD (-13%; P<0.01).

Conclusion: The variation of the analyzed structures could be an indicator of risk of progression with neurodegenerative (GCC) or vascular (choroid) pattern in the intermediate and atrophic AMD. The quantification of both structures can provide important information about the risk of disease progression in the early and intermediate stages but also for the evolution pattern into late stages (atrophic or neovascular).