Differential Effects of Aging in the Macular Retinal Layers, Neuroretinal Rim, and Peripapillary Retinal Nerve Fiber Layer

Abstract

Purpose: We determined the differential aging effects of the inner 6 layers of the macula in contrast to the minimum neuroretinal rim width (MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness.

Design: Cross-sectional, multicenter study.

Participants: An approximately equal number of white subjects with a normal ocular and visual field examination in each decade group from 20 to 90 years.

Methods: OCT of the macula, optic nerve head, and peripapillary retina.

Main outcome measures: Sectoral measurements of the inner 6 layers of the macula; age-related decline of each of these layers; strength of the associations with age of the macular parameters, MRW, and peripapillary RNFL thickness; and association between ganglion cell layer (GCL) thickness and MRW and peripapillary RNFL thickness.

Results: The study sample comprised 1 eye of 246 subjects with a median (range) age of 52.9 (19.8-87.3) years. Of the 6 layers, there was a statistically significant decline with age of only the GCL, inner plexiform layer, and inner nuclear layer thickness with rates of -0.11 μm/year, -0.07 μm/year, and -0.03 μm/year, respectively. These rates corresponded to 2.82%, 2.10%, and 0.78% loss per decade, respectively, and were generally uniform across sectors. The rate of loss of MRW and peripapillary RNFL thickness was -1.22 μm/year and -0.20 μm/year, corresponding to 3.75% and 2.03% loss per decade. However, the association of GCL thickness change with age (R² = 0.28) was approximately twice that of MRW and RNFL thickness (R² = 0.14 for each).

Conclusions: In concordance with histopathologic studies showing age-related loss of retinal ganglion cell axons, we showed a significant decline in GCL thickness, as well as MRW and peripapillary RNFL thickness. The stronger relationship between aging and GCL thickness compared with the rim or peripapillary RNFL may indicate that GCL thickness could be better suited to measure progression of structural glaucomatous loss.

Figure 1.

Sectoral mean thickness of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) in right eye format. The innermost circle has a diameter of 1 mm while the outermost circle has a diameter of 6 mm, with the diameter of each concentric circle incremented by 1 mm (key, upper right). Each circle, except the centermost one, is divided into twelve 30° sectors. Layer thicknesses are in gray scale with the lightest sectors showing highest values and darkest sectors showing thinnest values (key, bottom right). Mean value of each layer is indicated. S, superior; T, temporal; I, inferior; N, nasal.

Figure 2.

Mean thickness change of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) with age. Coefficient of determination (R²) and rate of loss shown for each layer. Line of best fit indicated for only those layers with a statistically significant change with age.

Figure 3.

Sectoral mean rate of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) thickness change with age in right eye format. The innermost circle has a diameter of 1 mm while the outermost circle has a diameter of 6 mm, with the diameter of each concentric circle incremented by 1 mm (key, upper right). Each circle, except the centermost one, is divided into twelve 30° sectors. Rates are in colour scale with the reddest sectors showing the most negative rates and greenest sectors showing the most positive rates (key, bottom right). Mean rate of change for each layer is indicated. S, superior; T, temporal; I, inferior; N, nasal.

Figure 4.

Sectoral mean rate of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) thickness change with age in right eye format expressed as a percentage. The innermost circle has a diameter of 1 mm while the outermost circle has a diameter of 6 mm, with the diameter of each concentric circle incremented by 1 mm (key, upper right). Each circle, except the centermost one, is divided into twelve 30° sectors. Rates are in colour scale with the reddest sectors showing the most negative rates and greenest sectors showing the most positive rates (key, bottom right). Mean percentage rate of change for each layer is indicated. S, superior; T, temporal; I, inferior; N, nasal.

Figure 5.

Relation between global minimum rim width (MRW) and peripapillary retinal nerve fibre layer (RNFL) thickness with age (−1.34 μm/y and −0.21 μm/y, respectively). Lines of best fit indicated and coefficients of determination (R²) are shown.

Figure 6.

Relation between macular ganglion cell layer (GCL) thickness and minimum rim width (MRW) and peripapillary retinal nerve fibre layer (RNFL) thickness globally (top) and in the temporal 90° sector (bottom). Pearson’s correlation coefficients (r) are indicated.