Abstract
The ultimate goal of the study is to provide an imaging tool to detect the earliest signs of glaucoma before clinically
visible damage occurs to the retinal nerve fiber layer (RNFL). Studies have shown that the optical reflectance of the
damaged RNFL at short wavelength (<560nm) is reduced much more than that at long wavelength, which provides
spectral contrasts for imaging the earliest damage to the RNFL. To image the spectral contrasts we built a dual-band
spectral-domain optical coherence tomography (SD-OCT) with centered wavelength of 415nm (VIS) and 808nm (NIR),
respectively. The light at the two bands was provided by the fundamental and frequency-doubled outputs of a broadband
Ti: Sapphire laser. The depth resolutions of the VIS and NIR OCT systems are 12.2 m and 4.7 m in the air. The system
was applied to imaging the rat retina in vivo. Significantly different appearances between the OCT cross sectional
images at the two bands are observed. The experimental results showed that the dual-band OCT system is feasible for
imaging the spectral contrasts of the RNFL.
