Purpose: We sought to establish normative ranges of the ganglion cell-inner plexiform layer (GCIPL) thickness using spectral-domain optical coherence tomography in Korean elderly individuals and to identify factors that influence GCIPL thickness.
Methods: We conducted a retrospective, observational study of 114 healthy subjects (75 years old or older) who underwent comprehensive ophthalmic examinations at a single institution. GCIPL thickness was measured with the Cirrus spectral-domain optical coherence tomography system and automatic segmentation. Subjects were divided into two age groups: those younger than 80 years and those 80 years or older, respectively. A cross-sectional analysis was adopted to evaluate associations of GCIPL thickness with sex, age, intraocular pressure, optic disc rim area, axial length, spherical equivalent (SE) refractive errors, astigmatism, and body mass index.
Results: The average and minimum GCIPL thicknesses were 80.3 ± 5.6 µm and 76.3 ± 5.9 µm, respectively. The GCIPL thickness was significantly lower in the older group than in the younger group in the inferior, inferonasal, and inferotemporal segments (all p < 0.01). A thinner average GCIPL thickness was strongly associated with increasing age (β = -2.87, p = 0.021) and thinner circumpapillary retinal nerve fiber layer thickness (β = 2.87, p < 0.001) in all segments.
Conclusions: GCIPL thickness decreased with age globally and in all segments, even after 75 years of age. Thinner GCIPL was associated with older age and thinner circumpapillary retinal nerve fiber layer. Age-related changes should be considered when using GCIPL thickness to assess glaucoma and other optic neuropathies characterized by retinal ganglion cell loss.
Keywords: Optical coherence tomography; Retina; Retinal ganglion cells.