Treatment of proliferative diabetic retinopathy by vitrectomy combined with retinal photocoagulation

AIM: To evaluate clinical effect of vitrectomy combined with retinal photocoagulation for proliferative diabetic retinopathy(PDR).<p>METHODS:A retrospective analysis 72 patients(104 eyes)with PDR who underwent vitrectomy, postoperative fundus fluorescein angiography and retinal photocoagulation within 4wk, from July 2009 to November 2012 in our hospital. All the patients were followed up for more than 12mo, analysising the clinical data of preoperative, postoperative, final corrected vision and the operation complications.<p>RESULTS:The increasing rate of visual acuity after retinal photocoagulation(the last retinal photocoagulation)within 1wk was 88.5%(92/104), 1mo was 92.3%(96/104), 3mo was 90.4%(94/104)and one eye had neovascular glaucoma, 6mo was 88.5%(92/104)and one eye had retinal detachment, 12mo was 80.8%(84/104)and 2 eyes with silicone oil emulsification. Along with the development of diabetic retinopathy, the increasing rate of visual acuity declined, complications of silicone oil eye operation increased, especially in eyes with proliferative diabetic retinopathy in phase five or six.<p>CONCLUSION:Vitrectomy combined with retinal photocoagulation in treatment of PDR is effective and safe. Postoperative fundus fluorescein angiography can have a definite object in view of retinal photocoagulation after vitrectomy, which can reduce excessive photocoagulation and prevent light coagulation deficiencies, while improve the visual acuity effectively and reduce the complications

Gamma rays and neutrinos from dark matter annihilation in galaxy clusters

The $\gamma$-ray and neutrino emissions from dark matter (DM) annihilation in galaxy clusters are studied. After about one year operation of Fermi-LAT, several nearby clusters are reported with stringent upper limits of GeV $\gamma$-ray emission. We use the Fermi-LAT upper limits of these clusters to constrain the DM model parameters. We find that the DM model distributed with substructures predicted in cold DM (CDM) scenario is strongly constrained by Fermi-LAT $\gamma$-ray data. Especially for the leptonic annihilation scenario which may account for the $e^{\pm}$ excesses discovered by PAMELA/Fermi-LAT/HESS, the constraint on the minimum mass of substructures is of the level $10^2-10^3$ M$_{\odot}$, which is much larger than that expected in CDM picture, but is consistent with a warm DM scenario. We further investigate the sensitivity of neutrino detections of the clusters by IceCube. It is found that neutrino detection is much more difficult than $\gamma$-rays. Only for very heavy DM ($\sim 10$ TeV) together with a considerable branching ratio to line neutrinos the neutrino sensitivity is comparable with that of $\gamma$-rays.Comment: 21 pages, 8 figures and 1 table; extended discussion about the uncertainties of concentration and subhalo models, figures replotted for better read; references updated; accepted for publication by Phys. Rev.