Changes in volume of various retinal layers over time in early and intermediate age-related macular degeneration

Abstract

Purpose To evaluate longitudinally volume changes in inner and outer retinal layers in early and intermediate age-related macular degeneration (AMD) compared to healthy control eyes using optical coherence tomography (OCT). Methods 71 eyes with AMD and 31 control eyes were imaged at two time points: baseline and after 2 years. Automated OCT layer segmentation was performed using Orion TM. This software is able to measure volumes of retinal layers with distinct boundaries including Retinal Nerve Fibre Layer (RNFL), Ganglion Cell-Inner Plexiform Layer (GCIPL), Inner Nuclear Layer (INL), Outer Plexiform Layer (OPL), Outer Nuclear Layer (ONL), Photoreceptors (PR) and Retinal Pigment Epithelium-Bruch's Membrane complex (RPE-BM). The mean retinal layer volumes and volume changes at 2 years were compared between groups. Results Mean GCIPL and INL volumes were lower, while PR and RPE-BM volumes were higher in AMD eyes than controls at baseline (all P < 0.05) and year 2 (all P < 0.05). In AMD eyes, RNFL and ONL volumes decreased by 0.0232 (P = 0.033) and 0.0851 (P = 0.001), respectively. In contrast, OPL and RPE-BM volumes increased in AMD eyes by 0.0391 (P = 0.000) and 0.0209 (P = 0.000) respectively. Moreover, there were significant differences in longitudinal volume change of OPL (P = 0.02), ONL (P = 0.008) and RPE-BM (P = 0.02) between AMD eyes and controls. Conclusions There were abnormal retinal layer volumes and volume changes in eyes with early and intermediate AMD.

Association of reduced inner retinal thicknesses with chronic kidney disease

“…For example, reduced thickness of the retinal ganglion cell complex (GCC; a composite retinal layer comprising the retinal layers containing the ganglion cell dendritic synapses with bipolar and amacrine cells, the ganglion cell bodies, and the ganglion cell axons viz., the IPL, GCL, and NFL respectively) has also been associated with a variety of ocular diseases in their early stages, such as glaucoma [56], retinal vessel loss in open-angle glaucoma [57], and chiasmal compression [58]. Similar changes have also been reported in early age-related macular degeneration [59]. This highlights the sensitivity of these layers to a variety of pathologies and also indicates the need to control for these conditions, where possible, in future analyses.…”

Focal Thickness Reduction of the Ganglion Cell-Inner Plexiform Layer Best Discriminates Prior Optic Neuritis in Patients With Multiple Sclerosis

“…Furthermore, the results obtained from the custom built UHR-OCT may limit the generalization of our current findings. However, the Orion Software used in the present study has been adapted in commercial OCT devices such as Zeiss Cirrus HD-OCT (with special data exportation), 44,45 Topcon 3D-1000 (Topcon Medical Systems, Inc., Oakland, NJ, USA), 46 and Spectralis SD OCT (Heidelberg Engineering, Heidelberg, Germany). 47 Our study can be repeated using these commercial OCT devices and the Orion software.…”

“…47 Our study can be repeated using these commercial OCT devices and the Orion software. [44][45][46][47] In addition, the visualized thickness reduction patterns may provide a reference for the clinical interpretation of OCT images using clinically available OCT devices. Third, the segmentation of intraretinal layers of each B-scan of the volumetric data set was not verified by the investigators, which constitutes a limitation.…”

Macula Ganglion Cell Thickness Changes Display Location-Specific Variation Patterns in Intermediate Age-Related Macular Degeneration

“…Other studies have shown changes in GCL thickness within a smaller macula area and with less dense spatial sampling. 9,[11][12][13][14][15]20,21 Both GCL thinning and thickening were observed in AMD eyes, with the latter more common. In support of our findings, GCL thickening has been reported recently by Brandl et al 21 in mild-early AMD (Three Continent AMD Consortium classification).…”

“…Of other previous literature, most actually contrast our work and Brandl's, suggesting GCL thinning to be more common in nonexudative AMD. The majority of these studies, however, have only implied GCL thinning as a component of the GCL-IPL complex thinning, [11][12][13][14][15]20 and have a number of other limitations, including small sample sizes, [11][12][13][14][15] a lack of age-matching, 12,13,15 auto-segmentation, [11][12][13][14][15]20 which has shown poorer variability compared to manual correction, 37 and less specific spatial analyses. 13,20 Our study accounted for these limitations by including a large sample size with age-matching, manual correction of segmentation when required, and a locationspecific methodology using grid analysis alongside macula spatial clusters, which have proven robust structure-function concordance.…”