Purchase this article with an account.
Aaron Michael Kho, Conrad M Merkle, Ratheesh Meleppata, Marcel Bernucci, Tingwei Zhang, Pengfei Zhang, SUMAN MANNA, Robert J Zawadzki, Vivek Jay Srinivasan; Wavelength-dependent OCT of the mouse retina in four spectral bands from visible to infrared. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5832.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Optical Coherence Tomography (OCT) retinal imaging in humans has historically been performed in two near-infrared spectral bands (800 nm and 1050 nm). To determine the light tissue interactions responsible for OCT contrast, and evaluate emerging spectral bands, we investigate wavelength-dependent reflectivity of different retinal layers using custom-built mouse retinal imaging systems operating in distinct spectral ranges (575 nm, 860 nm, 1060 nm, and 1325 nm).
We used four spectral domain (SD) or swept-source (SS) OCT systems for in vivo mouse retinal imaging: 575 nm (SD), 860 nm (SD), 1060 nm (SS), and 1325 nm (SD). System bandwidths ranged from ~100 nm-135 nm, and similar transverse resolutions were achieved by modifications to the scanning optics. Experiments were performed on 4-6 weeks old BALB/c (albino) and C57BL/6J (pigmented) mice (n=6) to investigate the effects of melanin on retinal reflectivity. The same eye was imaged in vivo under isoflurane anesthesia on all systems within 24 hours. Tropicamide or phenylephrine were applied topically for pupil dilation, and goniosol was applied with a contact lens on the cornea to maintain hydration. Volumetric data sets centered on the optic nerve were acquired. Eccentric locations were co-registered between systems using retinal and choroidal vessels as landmarks. Averaged A-scan profiles were generated at locations with similar eccentricity and quantitatively compared.
Penetration depth to the choroid and sclera decrease with wavelength and melanin content, consistent with the current understanding of retinal reflectivity in OCT. Outer retinal layer visibility improves without melanin in all spectral bands. Signals from directional layers such as the limiting membranes exhibit angle dependence with no obvious wavelength dependence.
Different spectral bands, from visible to infrared, highlight different retinal layers in OCT. Our results aid fundamental understanding of OCT contrast mechanisms, and will help to select the optimal wavelength range for various OCT imaging applications, ranging from the inner and outer retina to the choroid.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
OCT images of the pigmented (A-D) and albino (E-H) mouse retina acquired with 575 nm (A,E), 860 nm (B,F), 1060 nm (C,G), and 1325 nm (D,H) light.
Non-normalized log intensity line profiles of the pigmented (A) and albino (B) mouse retina with background correction done in linear scale.
This PDF is available to Subscribers Only