3D retinal imaging and measurement using light field technology

Abstract

. Significance: Light-field fundus photography has the potential to be a new milestone in ophthalmology. Up-to-date publications show only unsatisfactory image quality, preventing the use of depth measurements. We show that good image quality and, consequently, reliable depth measurements are possible, and we investigate the current challenges of this novel technology. Aim: We investigated whether light field (LF) imaging of the retina provides depth information, on which structures the depth is estimated, which illumination wavelength should be used, whether deeper layers are measurable, and what kinds of artifacts occur. Approach: The technical setup, a mydriatic fundus camera with an LF imager, and depth estimation were validated by an eye model and in vivo measurements of three healthy subjects and three subjects with suspected glaucoma. Comparisons between subjects and the corresponding optical coherence tomography (OCT) measurements were used for verification of the depth estimation. Results: This LF setup allowed for three-dimensional one-shot imaging and depth estimation of the optic disc with green light. In addition, a linear relationship was found between the depth estimates of the OCT and those of the setup developed here. This result is supported by the eye model study. Deeper layers were not measurable. Conclusions: If image artifacts can be handled, LF technology has the potential to help diagnose and monitor glaucoma risk at an early stage through a rapid, cost-effective one-shot technology.

Application of Artificial Intelligence in Precision Medicine for Diabetic Macular Edema

“…Further, a study by Arcadu et al 37 showed that DL could not only identify fundus color photographs with macular thickness >250 µm but also had the potential to predict specific values of fovea macular thickness from fundus photographs. Regarding hardware, Schramm et al 38 achieved 3-dimensional (3D) retinal imaging based on light field technology, and they successfully estimated the depth of the retina in one-shot imaging with an accuracy comparable to OCT measurement. This technology, combined with AI, is expected to improve the accuracy of DME screening further.…”

Three-Dimensional Light Field Fundus Imaging: Automatic Determination of Diagnostically Relevant Optic Nerve Head Parameters

“…In an effort to advance the state of the art in glaucoma diagnostics with none of the aforementioned limitations, a new method was developed that generates 3D images of the fundus with only one photographic shot via the use of a fundus camera in combination with light field (LF) technology. 24 – 27 Using this method, the entire LF is recorded with a microlens array that facilitates the reconstruction of depth information and provides a representation of the surface of the papilla. 28 A subsequent 3D analysis is also possible.…”

“… 28 A subsequent 3D analysis is also possible. A technical setup that could be used for papilla imaging was presented by Schramm et al 24 In this publication, the authors documented a method for LF imaging of the ONH and showed that relevant depths could be quantified in units of virtual mm (v-mm). However, calibration is needed to compare these results with data from other imaging systems.…”

“…Similarly, depth information can only be estimated from structures with a defined minimal degree of contrast, including the regions containing the blood vessels as well as the border and structures within the papilla. 24 , 25 As a result, the data are unevenly distributed. Additional artifacts are frequently overlaid on the data, including mis-estimated depths and frequencies.…”

“…Additional artifacts are frequently overlaid on the data, including mis-estimated depths and frequencies. 24 …”