APPLICATIONS  |  RETINAL IMAGING


 

Among all medical conditions where our technology can be applied, age related macular degeneration (AMD) has been identified as one of the most promising markets. Photon etc. technology is the only one that gives to health professionals a tool to establish an early diagnosis. This technology, now known MHRC* (Metabolic Hyperspectral Retinal Camera), was the starting point for one of Photon etc.’s "spin-off": Optina Diagnostics.

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.

MHRC 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. developed 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. MHRC 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.

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