Abstract
Purpose: :
To assess retinal oxygen saturation in glaucomatous eyes and to compare it with normal eyes, using slit-lamp adapted ultra-high resolution optical coherence tomography (SL-UHR-OCT).
Methods: :
SL-UHR-OCT was developed with a ~3µm depth resolution and light delivery scanning system mounted on a slit-lamp. Fringe patterns for spectral analysis of OCT images were obtained from the central retinal artery and vein. A-scans at the central wavelengths of 805 and 855 nm were analyzed for calculating optical density ratios (ODRs), which represent oxygen saturation in the retinal vessels.
Results: :
Seven eyes of 4 patients with perimetric glaucoma (treated IOP 14.6±3.3, visual field mean deviation 12.1±9.4 and pattern standard deviation 7.4±4.5) were imaged and compared with 20 eyes of 10 healthy subjects. ODR of the retinal artery was 0.21 ±0.17 in glaucomatous eyes, and was significantly lower than that of healthy controls (0.87 ± 0.57, p=0.003). ODR of the retinal vein was 0.06 ± 0.30 in glaucomatous eyes, which was not significantly different from healthy controls (0.20 ± 0.38, p=0.26). The usage of oxygen (ODR difference between artery and vein) was 0.15 ± 0.31 in glaucomatous eyes, which was significantly lower than that of normal controls (0.67 ± 0.63, p=0.03).
Conclusions: :
We demonstrated that oxygen saturation levels of the retinal artery and oxygen usage were lower in glaucoma patients compared with normal controls. Larger studies are required to examine the correlation between vascular dysfunction, oxygen saturation and structural changes in glaucoma.
Keywords: oxygen • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical