Wavelength dependence of the apparent diameter of retinal blood vessels

Abstract

Imaging of retinal blood vessels may assist in the diagnosis and monitoring of diseases such as glaucoma, diabetic retinopathy, and hypertension. However, close examination reveals that the contrast and apparent diameter of vessels are dependent on the wavelength of the illuminating light. In this study multispectral images of large arteries and veins within enucleated swine eyes are obtained with a modified fundus camera by use of intravitreal illumination. The diameters of selected vessels are measured as a function of wavelength by cross-sectional analysis. A fixed scale with spectrally independent dimension is placed above the retina to isolate the chromatic effects of the imaging system and eye. Significant apparent differences between arterial and venous diameters are found, with larger diameters observed at shorter wavelengths. These differences are due primarily to spectral absorption in the cylindrical blood column.

3D retinal imaging and measurement using light field technology

“…11 , 520 nm), which corresponds with findings from other publications. 28 , 29 Hence, most depth estimation points were found at that wavelength ( Fig. 12 ).…”

MEMS-based wearable eyeglasses for eye health monitoring

“…Figure 5 The reason for variation is that there are several factors that influence the appearance and size of retinal vessels as a function of wavelength. The most important factor is optical absorption by blood columns and vessels, as they have low contrast against fundus background for wavelengths longer than 600 nm [22]. In the vessels where blood thickness is greater absorption is high and where blood thickness is low, transmission is high.…”

Designing partial Mueller matrix polarimeters

“…Equation 6 can be interpreted by considering the structure of the inverse matrices. The inverse of the generator matrix is…”

“…1 Polarimeters can be placed into two main categories, passive Stokes vector polarimeters that measure the polarization state in an incoming optical field and active Mueller matrix polarimeters (MMPs) that probe the polarimetric scattering properties of optical processes. MMPs have been used in many sensing and metrology tasks including polarimetric LIDAR, 2 optical component metrology, 3 scattering characterization, 4 retinal opthalmology, 5,6 and microscopy, 7 among others. The theory of operation and calibration of MMPs was developed by Chipman,8 and the general formalism has been applied by many authors to the optimization of MMPs in the presence of noise and error.…”