In vivo retinal optical coherence tomography at 1040 nm - Enhanced penetration into the choroid

Optics Express (Impact Factor: 3.49). 06/2005; 13(9):3252-8. DOI: 10.1364/OPEX.13.003252
Source: PubMed


For the first time in vivo retinal imaging has been performed with a new compact, low noise Yb-based ASE source operating in the 1 microm range (NP Photonics, lambdac = 1040 nm, Deltalambda = 50 nm, Pout = 30 mW) at the dispersion minimum of water with ~7 microm axial resolution. OCT tomograms acquired at 800 nm are compared to those achieved at 1040 nm showing about 200 microm deeper penetration into the choroid below the retinal pigment epithelium. Retinal OCT at longer wavelengths significantly improves the visualization of the retinal pigment epithelium/choriocapillaris/choroids interface and superficial choroidal layers as well as reduces the scattering through turbid media and therefore might provide a better diagnosis tool for early stages of retinal pathologies such as age related macular degeneration which is accompanied by choroidal neovascularization, i.e., extensive growth of new blood vessels in the choroid and retina.

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    • "Advances in ocular imaging technology, such as the development of enhanced depth imaging (Spaide et al., 2008) and long wavelength (Unterhuber et al., 2005) optical coherence tomography (OCT), mean that the structure of the choroid can now be imaged and measured reliably invivo. Studies utilizing these OCT imaging methods, have substantially improved our understanding of the structure of the normal invivo human choroid. "
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    ABSTRACT: Changes in the thickness of the invivo peripapillary choroid have been documented in a range of ocular conditions in adults; however, choroidal thickness in the peripapillary region of children has not been examined in detail. This study therefore aimed to investigate the thickness of the peripapillary choroid and the overlying retinal nerve fibre layer (RNFL) in a population of normal children with a range of refractive errors. Ninety-three children (37 myopes and 56 non-myopes) aged between 11 and 16 years, had measurements of peripapillary choroidal and RNFL thickness derived from enhanced depth imaging optical coherence tomography images (EDI-OCT, Heidelberg Spectralis). The average thickness was determined in a series of five 0.25 mm width concentric annuli (each divided into 8 equal sized 45° sectors) centred on the optic nerve head boundary, accounting for individual ocular magnification factors and the disc-fovea angle. Significant variations in peripapillary choroidal thickness were found to occur with both annulus location (p < 0.001) and sector position (p < 0.001) in this population of children. The innermost annulus (closest to the edge of the optic disc) exhibited the thinnest choroid (mean 77 ± 16 μm) and the outermost annulus, the thickest choroid (191 ± 52 μm). The choroid was thinnest inferior to the optic nerve head (139 ± 38 μm) and was thickest in the superior temporal sector (157 ± 40 μm). Significant differences in the distribution of choroidal thickness were also associated with myopia, with myopic children having significantly thinner choroids in the inner and outer annuli of the nasal and temporal sectors respectively (p < 0.001). RNFL thickness also varied significantly with annulus location and sector (p < 0.001), and showed differences in thickness distribution associated with refractive error. This study establishes the normal variations in the thickness of the peripapillary choroid with radial distance and azimuthal angle from the optic nerve head boundary. A significant thinning of the peripapillary choroid associated with myopia in childhood was also observed in both nasal and temporal regions. The changes in peripapillary RNFL and choroidal thickness associated with refractive error are consistent with a redistribution of these tissues occurring with myopic axial elongation in childhood. Copyright © 2015. Published by Elsevier Ltd.
    Experimental Eye Research 03/2015; 135(6):164-173. DOI:10.1016/j.exer.2015.03.002 · 2.71 Impact Factor
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    • "The etiopathogenesis of RPC remains unknown, but both fluorescein and indocyanine green angiographic findings evidence involvement of the choroid altogether with the typical retinal changes [1]. The analysis of the choroidal morphologic and morphometric features has significantly improved with the development of high-penetrance optical coherence tomography (OCT) devices [4],[5]. The last generation of these integrates the swept-source (SS) laser technology. "
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    ABSTRACT: Background The purpose of this study is to evaluate the retinal and choroidal thickness of the macular region in patients with unilateral relentless placoid chorioretinitis (RPC) and macular involvement. Patients diagnosed with RPC affecting only one eye underwent a comprehensive ophthalmologic examination including best-corrected visual acuity (BCVA), axial length (AL) measurement, slit-lamp examination, and color fundus and autofluorescence photography. The macular region was scanned by swept-source optical coherence tomography in the 1,050-nm wavelength. Automated segmentations of the retina and the choroid were used to obtain the corresponding thickness values. Results A total number of three patients (two men and one woman; age range 17 to 62 years) were included. Eyes with clinically evident RPC had a mean AL of 24.62 ± 0.11 mm, whereas in the clinically healthy fellow eyes, the mean AL was 24.65 ± 0.03 (p = 0.70). The mean BCVA was 0.93 ± 0.16 in eyes with RPC, and 1.0 in all the fellow eyes (p = 0.70). Slit-lamp examination did not reveal any sign of vitreous inflammation in any cases. The mean macular retinal thickness was 288.10 ± 10.22 μm in eyes with RPC, and 300.30 ± 7.17 μm in the healthy fellow eyes (p = 0.20). The mean central choroidal thickness was 260.70 ± 140.60 μm in eyes with RPC, and 262.30 ± 123.10 μm in the fellow eyes (p = 0.99). The mean macular choroidal thickness was 248.60 ± 128.40 and 255.10 ± 123.60 μm, respectively (p = 0.99). Conclusions The pathogenesis of RPC remains unknown. No changes in the retinal and choroidal thickness were observed in the macular area of eyes diagnosed with RPC with macular involvement compared with the asymptomatic healthy fellow eyes. Further prospective studies are warranted in order to investigate the role of the choroid in cases of RPC.
    Journal of Ophthalmic Inflammation and Infection 10/2014; 4(1):24. DOI:10.1186/s12348-014-0024-x
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    • "In recent years other wavelength ranges gained more and more interest in research. Due to the water absorption minimum, lower scattering and therefore deeper tissue penetration the use of light centered around 1050 nm showed promising results especially in retinal imaging [12]. "
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    ABSTRACT: We present a newly developed single mode fiber based swept source polarization sensitive optical coherence tomography system using a single input state at 1040 nm. Two non-polarizing fiber based beam splitters are combined to form a Mach-Zehnder interferometer, while two polarizing beam splitters are used to obtain a polarization sensitive detection. Both types of beam splitters solely feature conventional single mode fibers. Polarization control paddles are used to set and maintain the polarization states in the fibers of the interferometer and detection unit. By use of a special paddle alignment scheme we are able to eliminate any bulk optic wave plates and polarization maintaining fibers in the interferometer and detection paths while preserving the advantages of a single input state system that illuminates the sample with circularly polarized light. To demonstrate the capabilities of our system, we performed retinal measurements on healthy human volunteers.
    Biomedical Optics Express 08/2014; 5(8):2798-2809. DOI:10.1364/BOE.5.002798 · 3.65 Impact Factor
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