●AIM:To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR)compared to those of PPV with subsequent cataract surgery.●METHODS:T...●AIM:To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR)compared to those of PPV with subsequent cataract surgery.●METHODS:This multicenter randomized controlled trial was conducted in three Chinese hospitals on patients with PDR,aged>45y,with mild cataracts.The participants were randomly assigned to the combined(PPV combined with simultaneously cataract surgery,i.e.,phacovitrectomy)or subsequent(PPV with subsequent cataract surgery 6mo later)group and followed up for 12mo.The primary outcome was the change in best-corrected visual acuity(BCVA)from baseline to 6mo,and the secondary outcomes included complication rates and medical expenses.●RESULTS:In total,129 patients with PDR were recruited and equally randomized(66 and 63 in the combined and subsequent groups respectively).The change in BCVA in the combined group[mean,36.90 letters;95%confidence interval(CI),30.35–43.45]was significantly better(adjusted difference,16.43;95%CI,8.77–24.08;P<0.001)than in the subsequent group(mean,22.40 letters;95%CI,15.55–29.24)6mo after the PPV,with no significant difference between the two groups at 12mo.The overall surgical risk of two sequential surgeries was significantly higher than that of the combined surgery for neovascular glaucoma(17.65%vs 3.77%,P=0.005).No significant differences were found in the photocoagulation spots,surgical time,and economic expenses between two groups.In the subsequent group,the duration of work incapacity(22.54±9.11d)was significantly longer(P<0.001)than that of the combined group(12.44±6.48d).●CONCLUSION:PDR patients aged over 45y with mild cataract can also benefit from early lens extraction during PPV with gratifying effectiveness,safety and convenience,compared to sequential surgeries.展开更多
以杏树为试材，为了解杏树冠层内透光率随树龄和叶面积指数的变化，采用LP-80型冠层分析仪测定了光合有效辐射PAR（Photosynthetically Active Radiation）在不同树龄杏树冠层三维空间上的分布情况，研究了杏树冠层内透光率随树龄（2-6...以杏树为试材，为了解杏树冠层内透光率随树龄和叶面积指数的变化，采用LP-80型冠层分析仪测定了光合有效辐射PAR（Photosynthetically Active Radiation）在不同树龄杏树冠层三维空间上的分布情况，研究了杏树冠层内透光率随树龄（2-6a）和叶面积指数的变化。结果表明，杏树冠层内部平均PAR的垂直分布具有随着向下累计叶面积指数的增加而递减的趋势，在冠层中上部，透光率较高，PAR递减很明显，冠层下部则维持较低水平，变化不大，在相同的天气和时间条件下不同树龄冠层内PAR同一相对高度的透光率有随树龄增加而递减的趋势，但在不同时刻不同天气条件下，即使同一棵树相同高度同一方位冠层内也具有不同的消光系数，影响杏树冠内光分布的因素是多样的，它们之间存在着复杂的关系；2～6年生杏树冠层中部的全天平均透光率分别为49．5％、30．0％、27．5％、13．4％和7．8％，冠层下部的平均透光率分别为29．1％、12．1％、10．9％、6．4％和5．9％；杏树冠层叶面积指数LAI（kaf Area Index）与透光率呈极显著指数相关关系，其表达式为Y=131．39e^-0．8963X（R^2=0．907^＊＊）；试验结果也可为果树冠层内PAR三维空间分布的模拟研究及冠层结构的优化提供试验方法和理论验证上的参考。展开更多
文摘●AIM:To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR)compared to those of PPV with subsequent cataract surgery.●METHODS:This multicenter randomized controlled trial was conducted in three Chinese hospitals on patients with PDR,aged>45y,with mild cataracts.The participants were randomly assigned to the combined(PPV combined with simultaneously cataract surgery,i.e.,phacovitrectomy)or subsequent(PPV with subsequent cataract surgery 6mo later)group and followed up for 12mo.The primary outcome was the change in best-corrected visual acuity(BCVA)from baseline to 6mo,and the secondary outcomes included complication rates and medical expenses.●RESULTS:In total,129 patients with PDR were recruited and equally randomized(66 and 63 in the combined and subsequent groups respectively).The change in BCVA in the combined group[mean,36.90 letters;95%confidence interval(CI),30.35–43.45]was significantly better(adjusted difference,16.43;95%CI,8.77–24.08;P<0.001)than in the subsequent group(mean,22.40 letters;95%CI,15.55–29.24)6mo after the PPV,with no significant difference between the two groups at 12mo.The overall surgical risk of two sequential surgeries was significantly higher than that of the combined surgery for neovascular glaucoma(17.65%vs 3.77%,P=0.005).No significant differences were found in the photocoagulation spots,surgical time,and economic expenses between two groups.In the subsequent group,the duration of work incapacity(22.54±9.11d)was significantly longer(P<0.001)than that of the combined group(12.44±6.48d).●CONCLUSION:PDR patients aged over 45y with mild cataract can also benefit from early lens extraction during PPV with gratifying effectiveness,safety and convenience,compared to sequential surgeries.
文摘以杏树为试材，为了解杏树冠层内透光率随树龄和叶面积指数的变化，采用LP-80型冠层分析仪测定了光合有效辐射PAR（Photosynthetically Active Radiation）在不同树龄杏树冠层三维空间上的分布情况，研究了杏树冠层内透光率随树龄（2-6a）和叶面积指数的变化。结果表明，杏树冠层内部平均PAR的垂直分布具有随着向下累计叶面积指数的增加而递减的趋势，在冠层中上部，透光率较高，PAR递减很明显，冠层下部则维持较低水平，变化不大，在相同的天气和时间条件下不同树龄冠层内PAR同一相对高度的透光率有随树龄增加而递减的趋势，但在不同时刻不同天气条件下，即使同一棵树相同高度同一方位冠层内也具有不同的消光系数，影响杏树冠内光分布的因素是多样的，它们之间存在着复杂的关系；2～6年生杏树冠层中部的全天平均透光率分别为49．5％、30．0％、27．5％、13．4％和7．8％，冠层下部的平均透光率分别为29．1％、12．1％、10．9％、6．4％和5．9％；杏树冠层叶面积指数LAI（kaf Area Index）与透光率呈极显著指数相关关系，其表达式为Y=131．39e^-0．8963X（R^2=0．907^＊＊）；试验结果也可为果树冠层内PAR三维空间分布的模拟研究及冠层结构的优化提供试验方法和理论验证上的参考。
