Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

Li, Hao; Liu, Wenzhong

doi:10.1117/1.jbo.20.10.106010

Cited by 8 publications

(9 citation statements)

References 29 publications

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“…We took fundus reflectance images to locate the region of interest through retinal landmarks, and took a fluorescence image immediately thereafter using a customized high-resolution rodent fundus camera. 43 The reflectance fundus images were taken using a narrow spectral-band illumination (halogen lamp with band-pass filter; bandwidth: 12.7 nm, center wavelength: 580 nm) to minimize chromatic aberrations. For fluorescence imaging, a 532-nm continuous-wave laser was combined into illumination optical path by a 45-degree laser-line mirror.…”

Section: Methodsmentioning

confidence: 99%

Sustaining Intravitreal Residence With L-Arginine Peptide-Conjugated Nanocarriers

Liu

Sorenson

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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PurposeIntravitreal injection of antiangiogenic agents is becoming a standard treatment for neovascular retinal diseases. Sustained release of therapeutics by injecting colloidal carriers is a promising approach to reduce the injection frequency, which reduces treatment burdens and the risk of complications on patients. Such sustained release often requires carriers to have micrometer-scale dimension that, however, can potentially promote glaucoma and inflammation. Small, polycationic particles can be immobilized in vitreous through multiple cooperative ionic interactions with hyaluronic acid of the vitreous interior, but such particles are generally toxic. Here, we synthesized and examined a biocompatible dextran-based nanocarrier (<50 nm in diameter) conjugated with cationic peptides containing L-arginine with minimal toxicity, aiming to provide sustained release of therapeutic drugs in vitreous.MethodsWe synthesized the nanocarriers with condensed cholesteryl dextran (CDEX) as core material. Cationic peptides containing 1 to 4 arginine groups, along with fluorescence tags, were conjugated to the CDEX surface. We monitored the carrier diffusion rate ex vivo and half-lives in vivo in rodent vitreous using fluorescence imaging. We evaluated the toxicity by histological examinations at the second, third, eighth, and thirty-sixth week.ResultsThe diffusion rate of nanocarriers was inversely related to zeta potential values in freshly isolated vitreous humor. We observed increased half-lives in vivo with increasing zeta potential (up to 240 days). Histological examinations confirmed no adverse effects on ocular morphology and organization.ConclusionsWe demonstrated the potential of L-arginine peptide-conjugated nanocarriers toward safe and sustained therapeutic release system for posterior eye diseases.

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Section: Methodsmentioning

confidence: 99%

Sustaining Intravitreal Residence With L-Arginine Peptide-Conjugated Nanocarriers

Liu

Sorenson

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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“…However, due to the optical quality of rodent eye, actual resolution during in vivo imaging will not achieve the theoretical values. 21 …”

Section: System Sensitivity and Imaging Resolutionmentioning

confidence: 99%

Dual-band optical coherence tomography using a single supercontinuum laser source

Chen

Xiao

et al. 2016

J. Biomed. Opt

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, "Dual-band optical coherence tomography using a single supercontinuum laser source," J. Biomed. Opt. 21(6), 066013 (2016) Abstract. We developed a simultaneous visible-light (Vis) and near-infrared (NIR) dual-band optical coherence tomography (OCT) system using a single supercontinuum laser source. The goal was to benchmark our newly developed Vis-OCT against the well-developed NIR-OCT. The Vis-OCT subsystem operated at 91 nm full-widthat-half-maximum (FWHM) bandwidth centered at 566 nm; the NIR-OCT subsystem operated at 93 nm FWHM bandwidth centered at 841 nm. The axial resolutions were 1.8 and 4.4 μm in air for the Vis-and NIR-OCT subsystems, respectively. We compared the respective performances, including anatomical imaging, angiography, absolute retinal blood flow measurements, and spectroscopic analysis for retinal blood oxygen saturation (sO 2 ), between the two subsystems in rodents in vivo. While demonstrating minor discrepancies related to operation wavelengths, both subsystems showed comparable performances in the first three tests. However, we were only able to retrieve sO 2 using the Vis-OCT subsystem.

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“…The quality of fundus images was then evaluated for any possible corneal clouding. We acquired the fundus images using a home-made high-resolution fundus camera 32 . The exposure time of fundus imaging was 0.2 s; the image resolution was 10 μm; and the field of view was 50 degrees.…”

Section: Resultsmentioning

confidence: 99%

“…6f . We compared the image qualities using a sharpness metrics analysis 32 33 . The sharpness M is defined as:…”

Section: Resultsmentioning

confidence: 99%

Fabricating customized hydrogel contact lens

Childs

Lewittes

et al. 2016

Sci Rep

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Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

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Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

Cited by 8 publications

References 29 publications

Sustaining Intravitreal Residence With L-Arginine Peptide-Conjugated Nanocarriers

Sustaining Intravitreal Residence With L-Arginine Peptide-Conjugated Nanocarriers

Dual-band optical coherence tomography using a single supercontinuum laser source

Fabricating customized hydrogel contact lens

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