Abstract
Purpose :
Geographic atrophy has long been thought to be a disease resulting in outer retinal layer loss, leaving the inner retinal layers (such as the ganglion cell layer) unaffected. Recent advances in imaging techniques have allowed en vivo measurements of these structures. Utilizing such technology, we aim to determine whether geographic atrophy results in ganglion cell layer (GCL) loss.
Methods :
Retrospective chart review of patients diagnosed with nonexudative macular degeneration and found to have geographic atrophy on dilated fundus examination. Patients were excluded if they had glaucoma or other retinal pathology that may distort normal retinal architecture. Optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA) images were analyzed utilizing the Ganglion Cell Analysis software to determine the GCL thickness. Only images attaining a signal strength of seven or greater were used for this analysis. These results were then compared to the normative data set used by the HD-OCT to provide an age matched control group.
Results :
Seventy-nine eyes from 53 patients were included and found to have an average GCL thickness of 58.0 ± 1.7 µm compared to the age-matched control of 76.5 ± 5.1 µm (p << 0.01). Images from multiple visits existed for 56 eyes allowing longitudinal analysis with average GCL thickness decreasing from 69.7 ± 1.9 to 60.8 ± 1.3 µm over 4.3 years (p << 0.01). Overlaying GCL thickness maps on OCT fundus images revealed numerous examples of GCL loss closely correlated with areas of geographic atrophy (Figure 1).
Conclusions :
These results support that geographic atrophy impacts the inner retinal layers in the form of ganglion cell layer loss. With the expanding utilization of ganglion cell layer loss as an indicator of glaucomatous damage, these findings must be considered when evaluating such patients.
This is a 2020 ARVO Annual Meeting abstract.