To compare the outer retinal thickness in normal fellow eyes of patients with unilateral age-related macular degeneration (AMD) and normal control eyes.

We retrospectively reviewed the medical records of 60 patients with unilateral exudative AMD including polypoidal choroidal vasculopathy and 60 normal controls. Spectralis optical coherence tomography was performed in the normal fellow eyes of patients with unilateral AMD and in the normal group. The thicknesses between the retinal pigment epithelium (RPE) line and the cone outer segment tips (COST) line, between the COST line and the photoreceptor inner segment/outer segment (IS/OS) line, and between the IS/OS line and the external limiting membrane (ELM) line were measured at the fovea in both groups.

The thickness between the RPE and COST lines was 32.4 ± 3.0 µm in normal fellow eyes of patients with unilateral AMD and 35.3 ± 3.5 µm in the normal group ( p < 0.001). Total retinal thickness, thicknesses between the COST and the IS/OS lines and the IS/OS and the ELM lines in fellow eyes were not significantly different from those of normal eyes ( p = 0.126, 0.615, 0.874). There was no significant difference in total retinal thickness or each outer retinal thickness measured in normal fellow eyes between patients with neovascular AMD and polypoidal choroidal vasculopathy.

The thickness between the RPE and the COST lines was thinner in the fellow eyes of patients with unilateral AMD than in the normal eyes. We suggest that less thickness between the RPE and COST lines might indicate a greater risk of AMD.