Abstract
Purpose: :
The retina consumes a large amount of oxygen similarly to the cerebrum. Oxygen deficiency induces retinal necrosis and the cytokines generated from hypoxic tissues make fragile neovessels, which may cause retinal detachment, blood vessel destruction, or glaucoma. Therefore, we developed the spectroscopic scanning laser ophthalmoscope (Spectroscopic SLO) to measure the oxygen saturation non-invasively.
Methods: :
Our developed system was based on the SLO produced by Nidek Co., Ltd. (Gamagori, Japan). The spectroscopic filter, a white-light illumination, a highly sensitive detector were installed in it to get spectroscopic images. The wavelength between 450 nm to 700 nm can be selected to measure the Q-band of hemoglobin. The six spectrum images detected by the spectroscopic-SLO were translated to the oxygen saturation using the principal component analysis.We employ the pre-dispersed illumination method for preventing too much exposure on retina. In our system, the exposure power was between 10-30 µW for getting the spectral retina images.
Results: :
We applied this system to clinical research under approved method by the Institutional Review Board (IRB). The one result for a healthy volunteer is shown below. Brightness of the picture shows the oxygen saturation on the retina. Arteries can readily distinguishable from veins for a healthy retina. We also show some cases focusing on diabetic retinopathy.
Conclusions: :
The developed spectroscopic-SLO can be used non-invasively for the oximetry on retina. Mapping of oxygen saturation on retina may enable the early detection of retinal diseases or elucidate their pathologic mechanisms.
Keywords: oxygen • imaging/image analysis: clinical • diabetic retinopathy