Longitudinal changes in the ganglion cell-inner plexiform layer thickness of age-related macular degeneration.

Purpose: To determine longitudinal changes of the ganglion cell-inner plexiform layer (GC-IPL) thickness in patients with non-exudative age-related macular degeneration (AMD) without other ophthalmic disease.

Methods: Thirty-three eyes of 33 patients with early and intermediate non-exudative AMD (non-exudative AMD group) and 33 normal control eyes were followed for 2 years, and GC-IPL thickness was measured by spectral domain optical coherence tomography at 1-year intervals. The mean rate of GC-IPL reduction was estimated using a linear mixed model and compared between two groups.

Results: The mean age of patients in the non-exudative AMD group and control groups were 68.82 ± 6.81 years and 67.73 ± 5.87 years, respectively (p = 0.488). The mean GC-IPL thickness at the first visit was 76.61 ± 16.33 μm in the non-exudative AMD and 81.76 ± 3.69 μm in control group (p = 0.387), and these values significantly decreased over time, with an average reduction rate of average GC-IPL -0.86 μm/year in the non-exudative AMD group and -0.32 μm/year in the control group. The difference between two groups was statistically significant (p < 0.001), and there was also a significant interaction between group and duration in linear mixed models in mean GC-IPL thickness (p = 0.001).

Conclusions: The reduction rate of the GC-IPL thickness was greater in non-exudative AMD eyes, even at relatively early stages of the disease. Physicians should maintain awareness of the presence of non-exudative AMD in various cases of ophthalmic diseases where GC-IPL thickness evaluation is necessary.