RETINAL IMAGING
Targeting the emergent field of retinal imaging, Photon etc. now offers a new hyperspectral system, IRISTM, particularly developed for ophthalmological studies.
The main component of this instrument is a custom-made mydriatic camera for the observation of the eye fundus (fig. 1). In combination to this, our tunable laser source (TLS) provides a safe and comfortable illumination of the subject’s eye at wavelengths from 420 to 1000 nm. The TLS is based on Photon etc’s Bragg grating filtering technology and allows for a rapid and accurate (<1 nm) wavelength selection from the supercontinuum source (Leukos-SM-30-OEM). In addition to this, an automatic spectral calibration system guarantees spectral reproducibility in time and an integrated photodiode provides the temporal normalization of the light intensity. The instrument includes a sensitive CCD camera for high definition imaging and comes with a chin rest and XYZ manual positioning system.
Our new retinal hyperspectral imager, IRISTM, allows the non-invasive localization of structures and biomolecules in the retina using their specific spectral signatures. In collaboration with the Glaucoma and Retina Research Group at the University of Waterloo/University Health Network, Photon etc. is developing a method to study retinal blood vessels and their blood oxygen saturation. In fact, the strong hemoglobin’s absorption at specific wavelengths in the visible spectrum (e.g. 585 nm) enhances the contrast of blood vessels (fig. 2). Since oxygenated hemoglobin (oxyhemoglobin) and deoxygenated hemoglobin (deoxyhemoglobin) show different absorption spectra, it is possible to distinguish between the arterioles (A), carrying oxygen-rich blood into the retina, and venules (V), carrying deoxygenated blood back to the heart (fig. 3).
At the light of this, it is possible to localize any other structure or biomolecule with spectral signatures and gather more information about eye disorders. IRISTM is the ideal research tool to better understand and develop tomorrow’s treatments for retinal diseases, such as diabetic retinopathy and age-related macular degeneration. This product is sold for research purposes only.
F2. Retinal image at 585 nm. The strong absorption of Hemoglobin enhances the contrast of blood vessels.
F3. Retinal image at 600 nm. The absorption spectrum of Hemoglobin varies according to its oxygen saturation and allows the distinction between arterioles (A) and venules (V).
