Development of a multispectral imaging apparatus for cost-effective fundus disease detection

Abstract

Fundus spectral imaging (FSI) integrates fundus photography with spectral techniques, providing both spatial and spectral information for retinal imaging. Whereas existing FSI systems have demonstrated advantages in structural and functional imaging, their widespread adoption is hindered by high costs and complex optical designs. To address these challenges, we propose a low-cost multispectral fundus camera with a simplified optical design, built from off-the-shelf optics, 3D-printed parts, and equipped with fiber-bundle-coupled multi-wavelength LED illumination source (470-740 nm). Additionally, the proposed multispectral imaging apparatus incorporates a coaxial non-separated polarization-based reflection suppression technique, using orthogonal polarizers to suppress corneal reflections without pupil-plane separation. To the best of our knowledge, this is the first application of such an architecture in the context of FSI. Experimental results demonstrate that the developed system achieves high-quality FSI under low-cost conditions, validating its feasibility as a practical solution. Clinical validation validates its diagnostic capability for diabetic retinopathy, choroidal pigmented nevus, and, notably, the first reported spectral imaging of peripapillary atrophy. The system achieves performance comparable to conventional color fundus photography while enabling superior diagnosis of deep fundus conditions such as choroidal lesions, offering a cost-effective and practical FSI solution for broader deployment in resource-limited settings.

Fig. 1.

Optical diagram of the fundus multispectral imaging system.

Fig. 2.

Spatial resolution and FOV testing of the prototype system. (A) Results of spatial resolution and FOV testing. (B) The prototype system. (C) A circular illumination spot comprising all selected wavelengths focused at the pupil plane.

Fig. 3.

Normalized spectral curves of nine used LEDs.

Fig. 4.

Fundus images at nine different wavelengths and the registered image of a volunteer’s right eye. The registered image was cropped and reconstructed from regions of images acquired at different wavelengths.

Fig. 5.

(A) Fundus tissues at 610 nm and (B) their corresponding spectral curves.

Fig. 6.

Fundus images of hard exudates in a case of DR. (A) Conventional color fundus image showing the location of hard exudates. (B-E) Corresponding multispectral images acquired at different wavelengths. The white arrows indicate the locations of the hard exudates.

Fig. 7.

Fundus images of a case with PPA. (A) Conventional color fundus image. (B-E) Corresponding multispectral images acquired at different wavelengths. White arrows indicate the location of the PPA.

Fig. 8.

Fundus images of a case with CPN. (A) Conventional color fundus image. (B-E) Corresponding multispectral images acquired at different wavelengths. White arrows indicate the location of the CPN.