Enhanced Grid-Based Visual Analysis of Retinal Layer Thickness with Optical Coherence Tomography

Abstract

Optical coherence tomography enables high-resolution 3D imaging of retinal layers in the human eye. The thickness of the layers is commonly assessed to understand a variety of retinal and systemic disorders. Yet, the thickness data are complex and currently need to be considerably reduced prior to further processing and analysis. This leads to a loss of information on localized variations in thickness, which is important for early detection of certain retinal diseases. We propose an enhanced grid-based reduction and exploration of retinal thickness data. Alternative grids are computed, their representation quality is rated, and best fitting grids for given thickness data are suggested. Selected grids are then visualized, adapted, and compared at different levels of granularity. A visual analysis tool bundles all computational, visual, and interactive means in a flexible user interface. We demonstrate the utility of our tool in a complementary analysis procedure, which eases the evaluation of ophthalmic study data. Ophthalmologists successfully applied our solution to study localized variations in thickness of retinal layers in patients with diabetes mellitus.

Thickness of Intraretinal Layers in Patients with Type 2 Diabetes Mellitus Depending on a Concomitant Diabetic Neuropathy: Results of a Cross-Sectional Study Using Deviation Maps for OCT Data Analysis

“…Using the VA software, GA and MA results for thickness deviation between patients and controls were generated. The concepts and algorithms involved in this process have been described previously [10,11]. The total thickness of the retina (TR) and the thickness of the RNFL, the GCL, the IPL and the inner nuclear layer (INL) were analyzed.…”

“…OCT data were analyzed with ETDRS-based deviation grids [ 11 ] in GA and via DevMs [ 2 ] in MA. Basically, both methods demonstrate the absolute thickness difference of a retinal layer between groups, although with distinct differences regarding the presentation of the results.…”

“…The technical design of our VA software and a detailed description of its main features regarding the GA and MA of retinal OCT thickness data have been published previously [2,10,11]. Here, we utilized the VA software to evaluate the previously recorded OCT data of T2DM patients with and without DN relative to controls and to compare the results obtained with both methods.…”

“…The resulting areas of significant differences were highlighted within the grids (orange cell borders and black cell labels) and within the maps (black outlines). OCT data were analyzed with ETDRS-based deviation grids [11] in GA and via DevMs [2] in MA. Basically, both methods demonstrate the absolute thickness difference of a retinal layer between groups, although with distinct differences regarding the presentation of the results.…”

“…To address these issues, we developed an analysis software based on visual analytics (VA) methods [10,11]. VA is a special field in computer science that offers means for simplifying the analysis of multiple volumetric OCT datasets by combining automated algorithms and human abilities to visually detect trends and patterns in the data.…”