Multispectral retinal image analysis: a novel non-invasive tool for retinal imaging

Abstract

Purpose To develop a non-invasive method for quantification of blood and pigment distributions across the posterior pole of the fundus from multispectral images using a computer-generated reflectance model of the fundus. Methods A computer model was developed to simulate light interaction with the fundus at different wavelengths. The distribution of macular pigment (MP) and retinal haemoglobins in the fundus was obtained by comparing the model predictions with multispectral image data at each pixel. Fundus images were acquired from 16 healthy subjects from various ethnic backgrounds and parametric maps showing the distribution of MP and of retinal haemoglobins throughout the posterior pole were computed. Results The relative distributions of MP and retinal haemoglobins in the subjects were successfully derived from multispectral images acquired at wavelengths 507, 525, 552, 585, 596, and 611 nm, providing certain conditions were met and eye movement between exposures was minimal. Recovery of other fundus pigments was not feasible and further development of the imaging technique and refinement of the software are necessary to understand the full potential of multispectral retinal image analysis. Conclusion The distributions of MP and retinal haemoglobins obtained in this preliminary investigation are in good agreement with published data on normal subjects. The ongoing development of the imaging system should allow for absolute parameter values to be computed. A further study will investigate subjects with known pathologies to determine the effectiveness of the method as a screening and diagnostic tool.

Multimodality Imaging in Diagnosing Polypoidal Choroidal Vasculopathy

“…Retinal structures and tissues observed in images depend on the reflectivity characteristics of the different parts of the fundus and this in turn depends on the distribution, quantities, and characteristic optical absorption properties of the pigments. 9 What deserves mention is that oxy-deoxy maps (including both the retinal map and choroidal map), which are the combined images of two wavelengths, reflect oxyhemoglobin in the retinal and choroidal vasculature. The oxy-deoxy maps are supposed to mimic the images in fundus fluorescein angiography and ICGA, because the vessels full of oxygenated blood have a different absorption pattern, which is hyperreflective (white in appearance), from blood that is not oxygenated, just as the enhanced images using a contrast medium.…”

Subspace approach in spectral color science

“…Eye fundus imaging is a common tool in studying eye and retina in clinical routines. During recent years the imaging technique has developed enabling use of spectral imaging of the eye fundus [35].…”

Comparison of image registration methods for composing spectral retinal images

“…The system captures a set of six channel images in approximately 0.5 s to avoid inter-channel eye movement [1]. The retina was illuminated at six selected wavelengths {507, 525, 552, 585, 596, 611} nm [10] using a halogen white-light source ltered through a liquid crystal tunable lter.…”

“…To evaluate the registration performance on real medical data, a semisynthetic test set was generated by deforming spectral retinal images taken with the system in [1]. The system captures a set of six channel images in approximately 0.5 s to avoid inter-channel eye movement [1].…”