Xuan-Chu Duan

The Second Xiangya Hospital of Central South University, Ch’ang-sha-shih, Hunan, China

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Publications (8)3.97 Total impact

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    ABSTRACT: Transdifferentiation of human Tenon fibroblasts to myofibroblasts and subsequent deposition of extracellular matrix is a key step in the scarring after glaucoma filtration surgery. The p38 signaling pathway plays an important role in cell proliferation and differentiation, and its upstream regulators and downstream molecules are widely distributed in the eye. We aimed to investigate the role of p38 in the activation of Tenon fibroblasts and that of the anti-fibrotic mechanism of rosiglitazone in the modulation of the p38 signaling pathway.
    PLoS ONE 01/2014; 9(8):e105796. · 3.73 Impact Factor
  • Ping-bo Ouyang, Xuan-chu Duan
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    ABSTRACT: The accumulating evidences from experimental and clinical studies suggested that the ocular surface could be injured by topical anti-glaucoma medications. The ocular surface injury not only caused dry eyes, red eye, eye itching, photophobia and other discomforts, but also increased the risk of failure of glaucoma surgery in patients. The commonly used preservative Benzalkonium Chloride (BAK) plays an important role in ocular surface damage and its side effects are dose- and time-dependent, particularly, in the combined medications. Topical application of preservative BAK could result in the damage of epithelial cells and endothelial cells, and also affect the central corneal thickness. Prevention of ocular injury should be seriously taken into consideration in the anti-glaucoma medical treatment. Development of complex preparations, preservative-free and/or novel preservative preparations for glaucoma therapy may provide a promising approach in the prevention of ocular surface injury.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 06/2012; 48(6):557-61.
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    ABSTRACT: To evaluate the repeatability of central corneal thickness (CCT) measurement by entacam, and agreement of CCT measured by Pentacam and ultrasound pachymetry (USP) in Chinese myopia. Thereby investigate the possibility of Pentacam as a substitute for USP in CCT measurement before refractive surgery. The effects of corneal curvature measured by Pentacam on CCT were also evaluated. One hundred and forty-eight right eyes of 148 individual with myopia were included in this study. Three successive Pentacam CCT measurements followed by 10 successive ultrasound pachymetry were carried out in the 148 eyes. Mean of CCT taken by each device was calculated for comparison. According to the CCT measured by USP, all the 148 eyes were divided into 3 groups: <520µm, 520-560µm, >560µm. For all eyes and each group the CCT obtained by Pentacam and USP were compared. Anterior corneal curvature of the 148 eyes was also adopted for correlation analysis with CCT obtained by ultrasound pachymetry. In addition, CCT measurement using 60 random selected Scheimpflug images was performed by 3 skilled investigators at different time, and this was repeated for 3 times by a forth investigator to assess repeatability of Pentacam CCT measurement using Scheimpflug images. Intraclass correlation coefficient (ICC) analysis revealed high intraobserver repeatability (ICC=0.994, F=158.60, P<0.001) for CCT measurement by Pentacam. The interobserver (ICC=0.998, F=494.73, P<0.001) and intraobserver (ICC=0.997, F=383.98, P<0.001) repeatability for Pentacam CCT measurements using Scheimpflug images were also excellent. There was high positive correlation between the CCT values measured by Pentacam and ultrasound pachymetry (r=0.963, P<0.001). Bland-altman plots showed that the Pentacam underestimate the CCT by 8.02µm compared with ultrasouond pachymetry. The differences between Pentacam and USP increased as the CCT readings by USP increased (Pentacam vs USP: slope=-0.04, P<0.05). The 95% upper and lower limits of agreement between CCT values obtained from the two devices were +9.33µm and -25.37µm. No significant association could be found between CCT and anterior corneal curvature. Inter- and intraobserver variability for CCT measurements by Pentacam was considerably below clinically significant levels. CCT of myopia obtained by Scheimpflug camera, Pentacam, were highly correlated to that by ultrasound pachymetry. However, the values obtained are not directly interchangeable between Pentacam and ultrasound pachymetry as the 95% limits of agreement are relatively wide. Pentacam can be a useful instrument for measuring CCT in candidates to refractive surgery in clinic.
    International journal of ophthalmology. 01/2012; 5(3):329-33.
  • Ping-Bo Ouyang, Xuan-Chu Duan, Xiao-Hua Zhu
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    ABSTRACT: In recent years, the broad application of optical coherence tomography and vitrectomy, combined with research efforts in maculopathy in high myopia have provided many achievements, such as the new classification of myopic traction maculopathy (MTM). Here, we review the latest developments in the diagnosis and treatment of MTM, including its conception, clinical characteristics, pathogenesis, clinical stages, and the options for surgical treatment.
    International Journal of Ophthalmology 01/2012; 5(6):754-8. · 0.12 Impact Factor
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    ABSTRACT: To investigate the accuracy of intraocular pressure (IOP) as measured by a Reichert Ocular Response Analyzer (ORA), as well as the relationship between central corneal thickness (CCT) and IOP as measured by ORA, Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT). A total of 158 healthy individuals (296 eyes) were chosen randomly for measurement of IOP. After CCT was measured using A-ultrasound (A-US), IOP was measured by ORA, GAT, and DCT devices in a randomized order. The IOP values acquired using each of the three tonometries were compared, and the relationship between CCT and IOP values were analyzed separately. Two IOP values, Goldmann-correlated IOP value (IOPg) and corneal-compensated intraocular pressure (IOPcc), were got using ORA. Three groups were defined according to CCT: 1) thin cornea (CCT<520µm); 2) normal-thickness cornea (CCT: 520-580µm); and 3) thick cornea (CCT>580µm) groups. In normal subjects, IOP measurements were 14.95±2.99mmHg with ORA (IOPg), 15.21±2.77mmHg with ORA (IOPcc), 15.22±2.77mmHg with GAT, and 15.49±2.56mmHg with DCT. Mean differences were 0.01±2.29mmHg between IOPcc and GAT (P>0.05) and 0.28±2.20mmHg between IOPcc and DCT (P>0.05). There was a greater correlation between IOPcc and DCT (r=0.946, P=0.000) than that between IOPcc and GAT (r=0.845, P=0.000). DCT had a significant correlation with GAT (r=0.854, P=0.000). GAT was moderately correlated with CCT (r=0.296, P<0.001), while IOPcc showed a weak but significant correlation with CCT (r=-0.155, P=0.007). There was a strong negative correlation between CCT and the difference between IOPcc and GAT(r=-0.803, P=0.000), with every 10µm increase in CCT resulting in an increase in this difference of 0.35mmHg. The thick cornea group (CCT>580µm) showed the least significant correlation between IOPcc and GAT (r=0.859, P=0.000); while the thin cornea group (CCT<520µm) had the most significant correlation between IOPcc and GAT (r=0.926, P=0.000). The correlated differences between IOPcc and DCT were not significant in any of the three groups (P>0.05). Measurement of IOP by ORA has high repeatability and is largely consistent with GAT measurements. Moreover, the ORA measurements are affected only to a small extent by CCT, and are likely to be much closer to the real IOP value than GAT.
    International journal of ophthalmology. 01/2012; 5(1):102-7.
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    ABSTRACT: To compare the efficacy of prophylactic vitrectomy for acute retinal necrosis syndrome(ARN) with routine treatment in Chinese patients, thereby investigate the necessity of prophylactic vitrectomy for ARN. Thirty patients (37 eyes) were retrospectively included in this study. The eyes were divided into 2 groups by treatment, including routine treatment, which consisted of antiviral medication and vitrectomy after retinal detachment (RD) (n=21), and prophylactic vitrectomy, which consisted of antiviral medication and vitrectomy for the prevention of RD performed during the active inflammatory phase (n=16). The extent of necrosis was determined by fundus photographs at the time of presentation (for eyes with mild vitreous opacity) or the drawings in the operation records. Necrosis of the 37 eyes was divided into 3 grades, including peripheral, middle-peripheral and extensive. The follow-up period ranged from 8 to 57 months. Differences in visual acuity and necrosis between groups were identified using independent samples t-test. Necrosis was more extensive in the routine treatment group than in the prophylactic vitrectomy group (P<0.05). In the routine treatment group, conservative treatment improved necrosis and prevented RD in 6 eyes (29%). Seven eyes (33%) obtained anatomical success, but retinal redetachment occurred in 8 eyes (57%). There were also 5 eyes (24%) developed ocular hypotony or atrophy. Ten eyes (48%) achieved equal or increased visual acuity. In the prophylactic vitrectomy group, RD occurred in 2 eyes (13%). Twelve eyes (75%) were completely anatomically successful, and 10 eyes underwent silicone oil removal. Only one eye (6%) became ocular hypotony. Fourteen eyes (88%) achieved equal or increased visual acuity. The prophylactic vitrectomy group achieved better vision trends than the routine treatment group (P<0.05). Eyes with peripheral necrosis had better visual outcomes than those with mid-peripheral (P<0.05) or extensive (P<0.05) necrosis. However, there was no significant difference between eyes with mid-peripheral and extensive necrosis (P=0.3008) Prophylactic vitrectomy can prevent RD and improve the prognosis of ARN, making it an option for cases with rapidly progressing necrosis despite antiviral treatment and cases with moderate to extensive necrosis and severe vitreous opacity.
    International journal of ophthalmology. 01/2012; 5(4):482-7.
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    Xuan Zou, Xuan-Chu Duan, Qian Zhong
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    ABSTRACT: To study the effects of gender, eye side and age on anterior chamber measurements; To compare the anterior chamber parameters between glaucoma and normal subjects. A total of 169 patients (299 eyes), of which 122 normal subjects (218 eyes), 24 cases (39 eyes) with primary angle-closure glaucoma (PACG) and 22 cases (42 eyes) with primary open-angle glaucoma (POAG) visiting our hospital from Apr. 2008 to Oct. 2008 were enrolled. The parameters measured by Pentacam between different sexes, eye sides, ages and different groups were compared. The mean central anterior chamber depth (CACD), anterior chamber volume (ACV) and anterior chamber angle (ACA) measurements of normal eyes were 2.82±0.43mm, 159.74±43.64mm(3) and 35.47±7.92°. There were no significant differences between different eye sides. There was a negative correlation between age and anterior chamber parameters (all P<0.001); The mean CACD, ACV and ACA were 1.87±0.29mm, 82.00±24.17mm(3) and 21.94±7.11° in PACG group, and 2.67±0.34mm, 147.24±43.40mm(3) and 31.19±6.34° in POAG group. The differences between PACG and age-matched normal subjects were significant (all P<0.05), but there was no significant difference between POAG and age-matched normal subjects (P>0.05). CACD, ACV and ACA decrease mildly with age. Anterior chamber parameters of PACG are smaller than that of normal eyes, but there is no difference between POAG and normal eyes.
    International Journal of Ophthalmology 01/2010; 3(4):349-51. · 0.12 Impact Factor
  • Xuan Zou, Xuan-Chu Duan
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    ABSTRACT: Glaucoma drainage device (GDD) is moderately successful in patients with refractory glaucoma. However, bleb fibrosis appears to be the major cause of long-term GDD failure. In recent years, many researchers tried to explain the cause of fibrosis and its influence on the clinical effects of GDD from histopathological study. It has reported that antifibrotic agents are effective in controlling capsule fibrosis around GDD, but this view has been challenged recently. Although GDD can effectively reduce the intraocular pressure (IOP) in refractory glaucoma, it is associated with many serious complications, such as endophthalmitis, corneal decompensation and hypotony. Because of the disadvantages of GDD, many new implant and modified surgical technique emerged in recent years. The anterior segment OCT is able to visualize the whole outline and the position of the tube, therefore it is useful for guiding the postoperative treatment. Furthermore, the application of novel materials and nanotechnology could open up new avenues for GDD.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 06/2009; 45(6):567-73.

Publication Stats

2 Citations
3.97 Total Impact Points

Institutions

  • 2012
    • The Second Xiangya Hospital of Central South University
      Ch’ang-sha-shih, Hunan, China
  • 2009
    • Central South University
      • Department of Ophthalmology
      Changsha, Hunan, China