1. Articles from Qi Chen

    1-13 of 13
    1. Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

      Axial elongation measured by long scan depth optical coherence tomography during pilocarpine-induced accommodation in intraocular lens-implanted eyes

      We used an ultra-long scan depth optical coherence tomography (UL-OCT) system to investigate changes in axial biometry of pseudophakic eyes during pilocarpine- induced accommodation. The right eyes from 25 healthy subjects (age range 49 to 84 years) with an intraocular lens (IOL) were imaged twice in the non-accommodative and the accommodative states. A custom-built UL-OCT instrument imaged the whole eye. Then accommodation was induced by two drops of 0.5% pilocarpine hydrochloride separated by a 5-minute interval. Following the same protocol, images were acquired again 30 minutes after the first drop. The central corneal thickness (CCT), anterior chamber depth (ACD ...

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    2. Biometry of Anterior Segment of Human Eye on Both Horizontal and Vertical Meridians during Accommodation Imaged with Extended Scan Depth Optical Coherence Tomography

      Biometry of Anterior Segment of Human Eye on Both Horizontal and Vertical Meridians during Accommodation Imaged with Extended Scan Depth Optical Coherence Tomography

      Purpose To determine the biometry of anterior segment dimensions of the human eye on both horizontal and vertical meridians with extended scan depth optical coherence tomography (OCT) during accommodation. Methods Twenty pre-presbyopic volunteers, aged between 24 and 30, were recruited. The ocular anterior segment of each subject was imaged using an extended scan depth OCT under non- and 3.0 diopters (D) of accommodative demands on both horizontal and vertical meridians. All the images were analyzed to yield the following parameters: pupil diameter (PD), anterior chamber depth (ACD), anterior and posterior surface curvatures of the crystalline lens (ASC and PSC ...

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    3. Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

      Fully Automated Biometry of In Situ Intraocular Lenses Using Long Scan Depth Spectral-Domain Optical Coherence Tomography

      Purpose: Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. Methods: Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results ...

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    4. Ocular anterior segment biometry and high-order wavefront aberrations during accommodation

      Ocular anterior segment biometry and high-order wavefront aberrations during accommodation

      Purpose: To investigate the relationships between the ocular anterior segment biometry and the ocular high-order aberrations (HOAs) during accommodation by combined ultra-long scan depth optical coherence tomography (UL-OCT) and wavefront sensor. Methods: Thirty-five right eyes of young healthy subjects (21 women and 14 men; age: 25.6 ± 3.1 years; spherical equivalent refractive error: -0.41 ± 0.59 D) were enrolled. A custom-built UL-OCT and a wavefront sensor were combined. They were able to image the ocular anterior segment and to measure the HOAs during accommodation. The differences in the biometric dimensions and in the HOAs between the non-accommodative and ...

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    5. Ultra-High Resolution Optical Coherence Tomography for Imaging the Anterior Segment of the Eye

      Ultra-High Resolution Optical Coherence Tomography for Imaging the Anterior Segment of the Eye

      Developments in optical coherence tomography (OCT) have expanded its clinical applications for ultra-high resolution imaging of the anterior segment of the human eye. This review presents the latest advances for imaging the anterior segment of the eye using ultra-high resolution OCT (UHR-OCT). Unique applications of UHR-OCT technology in clinical and basic scientific laboratory research are discussed and a summary of the results is provided. The authors focused on the use of UHR-OCT for imaging of tear dynamics, contact lens interactions with the corneal surface, and in vivo histological diagnosis of disorders of the cornea, as well as the future direction ...

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    6. Topographic Thickness of Bowman's Layer Determined by Ultra-High Resolution Spectral Domain–Optical Coherence Tomography

      Topographic Thickness of Bowman's Layer Determined by Ultra-High Resolution Spectral Domain–Optical Coherence Tomography
      Purpose. To characterize the thickness profile of the corneal epithelium and the Bowman's layer across the horizontal meridian. Methods. Forty-four eyes of 22 healthy subjects were investigated in this study. Ultra-high resolution anterior segment spectral domain–optical coherence tomography (SD-OCT) was used to assess the topographic thickness of the epithelium and the Bowman's layer across the cornea. Thicknesses at five locations, including the center, midperiphery, and periphery close to the limbus, on both the nasal and the temporal sides along the horizontal meridian, were analyzed. Results. Mean epithelial thickness at the central cornea was 52.5 ± 2.4 ...
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    7. Topographical thickness of Bowman's layer determined by ultra-high resolution spectral domain optical coherence tomography

      Topographical thickness of Bowman's layer determined by ultra-high resolution spectral domain optical coherence tomography
      Purpose: To characterize the thickness profile of the corneal epithelium and Bowman's layer across the horizontal meridian. Methods: Forty-four eyes of 22 normal subjects were investigated in this study. Ultra-high resolution anterior segment spectral domain optical coherence tomography (SD-OCT) was used to assess the topographical thickness of the epithelium and Bowman's layer across the cornea. The thickness at five locations, including the center, mid-periphery, and periphery close to the limbus, on both nasal and temporal sides along the horizontal meridian was analyzed. Results: The mean epithelial thickness at the central cornea was 52.5 ± 2.4 μm. It ...
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    8. Tear Dynamics and Corneal Confocal Microscopy of Subjects with Mild Self-Reported Office Dry Eye

      Tear Dynamics and Corneal Confocal Microscopy of Subjects with Mild Self-Reported Office Dry Eye
      Purpose To investigate changes in tear dynamics and corneal microstructure in mild self-reported office dry eye. Design Prospective laboratory investigation. Participants Twenty healthy office workers, 20 office workers with mild self-reported dry eye, and 20 office workers with moderate to severe dry eye as determined by the Ocular Surface Disease Index (OSDI). Methods Real-time anterior segment optical coherence tomography was used to obtain upper (UTMV), lower (LTMV), tear meniscus volumes. The total tear meniscus volume (TTMV) was the sum of the UTMV and LTMV. This was followed by measurement of noninvasive tear breakup time (NITBUT), fluorescein tear breakup time (FTBUT ...
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    9. Ultrahigh-Resolution Measurement by Optical Coherence Tomography of Dynamic Tear Film Changes on Contact Lenses

      Purpose. To determine the dynamic pre- and postlens tear film (PLTF and PoLTF) thicknesses by using optical coherence tomography (OCT). Methods. Ultrahigh-resolution OCT was used to image the tear film of 22 subjects before and after contact lens wear. A soft lens with 1 drop of artificial tears on its concave surface was inserted onto one randomly selected eye. OCT images were taken before insertion, immediately afterward, and every 2 minutes for 10 minutes. For the contralateral eye, the lens inserted was not prewetted on the concave surface. OCT images were taken before insertion, immediately afterward, and at 3 minutes ...
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    10. Use of Ultra-High-Resolution Optical Coherence Tomography to Detect in Vivo Characteristics of Descemet's Membrane in Fuchs' Dystrophy

      Purpose: To demonstrate the capability of ultra-high-resolution (UHR) anterior segment optical coherence tomography (OCT) to image Descemet's membrane (DM) and measure its thickness in vivo. (2) To evaluate the use of DM characteristics and thickness in the diagnosis of Fuchs' dystrophy.Design: Case-control study.Participants: Twenty eyes of 12 Fuchs' dystrophy patients, 20 eyes of 13 young normal, and 20 eyes of 15 elderly normal subjects.Methods: Subjects were imaged using novel, custom-built UHR-OCT. Images were used to describe the characteristics of DM. Custom-made software was used to measure DM thickness and central corneal thickness (CCT). Specimens of DM ...
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    11. Ultra-high Resolution Measurement by Optical Coherence Tomography of Dynamic Tear Film Changes on Contact Lenses

      Purpose: To determine the dynamic pre- (PLTF) and post-lens (PoLTF) tear film thicknesses using optical coherence tomography (OCT). Methods: Ultra-high resolution OCT was used to image the tear film of 22 subjects before and after contact lens wear. A soft lens with one drop of artificial tears on its concave surface was inserted onto one randomly selected eye. OCT images were taken before insertion, immediately afterwards, and every 2 minutes for 10 minutes. For the contralateral eye, the lens inserted was not pre-wetted on the concave surface. OCT images were taken before insertion, immediately afterwards, and at 3 minutes. Then ...
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    12. Lower volumes of tear menisci are associated with dry eye symptoms in contact lens wearers

      Purpose: To investigate tear meniscus volumes during short-term wear by soft contact lens (SCL) wearers with dryness symptoms. Methods: Three groups of 20 subjects were recruited. Group 1 consisted of SCL wearers with self-reported dryness. Group 2 consisted of asymptomatic wearers. Group 3 was composed of asymptomatic non-lens wearers. Contact lenses were fitted on each eye, and both upper and lower tear menisci were imaged before lens insertion, immediately afterwards, and 30 min later, using optical coherence tomography. Custom software was used to yield the tear meniscus area and then the volumes were calculated based on eyelid length. Repeatability was ...
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    13. In Situ Visualization of Tears on Contact Lens Using Ultra High Resolution Optical Coherence Tomography.

      Objective: To demonstrate the capability of directly visualizing the tear film on contact lenses using optical coherence tomography (OCT). Methods: Six eyes of three healthy subjects wearing PureVision and ACUVUE Advance soft and Boston RGP hard contact lenses were imaged with a custom built, high speed, ultra-high resolution spectral domain optical coherence tomograph. Refresh Liquigel was used to demonstrate the effect of artificial tears on the tear film. Results: Ultra high resolution images of the pre- and post-lens films were directly visualized when each lens was inserted onto the eye. After the instillation of artificial tears during lens wear, the ...
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    1-13 of 13
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    1. (13 articles) Qi Chen
    2. (11 articles) Wenzhou Medical College
    3. (11 articles) Jianhua Wang
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    6. (5 articles) Aizhu Tao
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