To determine longitudinal changes in the ganglion cell–inner plexiform layer (GC-IPL) thickness of the fellow eyes of patients with neovascular age-related macular degeneration (AMD).

Prospective cohort study.

Patients with unilateral neovascular AMD, unilateral polypoidal choroidal vasculopathy (PCV), and control subjects were included. After the initial visit, GC-IPL thickness was measured twice more with at least a 1-year interval between examinations using spectral domain optical coherence tomography.

Twenty-seven fellow eyes of patients with unilateral choroidal neovascularization (CNV), 33 fellow eyes of patients with unilateral PCV, and 35 eyes of control subjects were enrolled. The GC-IPL thickness of the fellow eyes was 78.41 ± 9.23, 81.20 ± 5.52, and 81.60 ± 3.83 μm in the CNV, PCV, and control groups, respectively, and they showed a significant change over time (P < .001, P = .001, and P = .003, respectively). The reduction rate of GC-IPL thickness was −0.88, −0.41, and −0.31 μm per year in the fellow eyes of the CNV, PCV, and control groups, respectively (CNV > PCV, control, P < .001). In a linear mixed model determination of factors associated with GC-IPL reduction in the fellow eyes of the CNV group, the interaction between baseline GC-IPL thickness and duration showed a significant result (P < .001).

The fellow eyes of patients with neovascular AMD showed a greater reduction rate of GC-IPL thickness compared with fellow eyes of patients with unilateral PCV and control subjects. In patients with unilateral neovascular AMD, fellow eyes with a thicker GC-IPL at baseline showed a greater reduction in GC-IPL thickness over time.