Purpose:
Practical implementation of retinal oximetry must lead to earlydetection of retinal diseases. As the retina consumes a largeamount of oxygen similarly to the cerebrum, insufficient oxygeninduces retinal necrosis and the cytokines generated from hypoxictissues make fragile neovessels, which may cause retinal detachment,blood vessel destruction, or glaucoma. Therefore, we developedthe spectroscopic scanning laser ophthalmoscope (SpectroscopicSLO) to measure the oxygen saturation non-invasively. The spectroscopic-SLOcan be used without the mydriatic and the injection of contrastdye, which is suitable for screening tests.
Methods:
We added a spectroscopic feature to a SLO produced by NidekCo., Ltd. (Gamagori, Japan). The spectroscopic filter, a white-lightillumination, a highly sensitive detector were installed init to get spectroscopic images. The wavelength between 450 nmto 700 nm can be selected to measure the Q-band of hemoglobin.The five spectrum images detected by the spectroscopic-SLO weretranslated to the oxygen saturation using the partial leastsquare analysis. We employ the pre-dispersed illumination methodfor preventing too much exposure on retina. In our system, theexposure power was between 10-30 µW for getting the retinalspectral images.
Results:
We applied this system to clinical research under approved methodby the Institutional Review Board (IRB). The one result fora healthy volunteer is shown below. Brightness of the pictureshows the oxygen saturation on the retina. Arteries can readilydistinguishable from veins for a healthy retina. We show somecases focusing on diabetic retinopathy.
Keywords: blood supply • diabetic retinopathy • hypoxia