Prevalence of vitreous floaters in a community sample of smartphone users

AIM: To estimate the prevalence and risk factors for vitreous floaters in the general population. ·METHODS: An electronic survey was administered through a smartphone app asking various demographic and health questions, including whether users experience floaters in their field of vision. Multivariate logistic regression analysis was used to determine risk factors. ·RESULTS: A total of 603 individuals completed the survey, with 76% reporting that they see floaters, and 33% reporting that floaters caused noticeable impairment in vision. Myopes were 3.5 times more likely (P =0.0004), and hyperopes 4.4 times more likely (P =0.0069) to report moderate to severe floaters compared to those with normal vision. Floater prevalence was not significantly affected by respondent age, race, gender, and eye color. ·CONCLUSION: Vitreous floaters were found to be a very common phenomenon in this non -clinical general population sample, and more likely to be impairing in myopes and hyperopes.

Pars plana vitrectomy relieves the depression in patients with symptomatic vitreous floaters

AIM:To investigate the depressive state among the patients with symptomatic vitreous floaters(SVF),as well as its change after SVF removal via vitrectomy surgery.METHODS:Twenty-eight eyes of 28 patients who underwent 27-gauge pars plana vitrectomy(PPV)for SVF were included.Thirty-nine eyes of 39 age-and gendermatched healthy volunteers without SVF were also recruited as a healthy control.Center for Epidemiologic Studies Depression(CES-D)was used to assess volunteers and patients’depression(before and 1 wk after PPV).RESULTS:The CES-D score was 18.3±8.6 for patients,and was 12.4±6.0 for healthy control(P=0.003).Patients were significantly more likely to be in a depressive state(53.6%,defined as CES-D score≥16)than the healthy control(20.5%,P=0.005).For patients with SVF,the CES-D score was negatively correlated with their age(rs=-0.42,P=0.025).After PPV,both the CES-D score(11.9±5.4 vs 18.3±8.6,P<0.001)and proportion of depressive state(18.5%vs 53.6%,P=0.005)were significantly decreased.CONCLUSION:This study suggests that symptoms of vitreous floaters have an apparently negative impact on patients’psychological state.The PPV can effectively relieve the depressive state for patients with SVF.

Long-term efficacy and safety of YAG laser vitreolysis for vision degrading myodesopsia

AIM:To assess the long-term efficacy and safety of yttrium-aluminum garnet(YAG)laser vitreolysis for vision degrading myodesopsia(VDM)caused by posterior vitreous detachment(PVD).METHODS:This retrospective study reviewed VDM patients of PVD type undergoing YAG laser vitreolysis.The baseline demographic information,the patterns of floaters,the number of floaters,and the subjective improvement of floater sympotoms(ranging from 0 to 100%)from medical records were collected.Significant improvement was defined as a relief of floater symptoms of≥50%at the final visit.The long-term efficacy and safety of YAG laser vitreolysis were analyzed.The risk factors linked to significant improvement of floater symptoms were defined using univariate and multivariate logistic regression analyses.RESULTS:The final analysis included 221 patients with VDM.The mean age of patients was 61.08±7.74y,and the mean length of follow-up was 21.38±5.61mo.Totally 57.01%of patients experienced a significant improvement in their floater symptoms after YAG laser therapy,and none of them developed delayed retinal abnormalities such as retinal tears or detachments.Age(OR=1.049,95%CI=1.007-1.092,P=0.021)was identified as a significant risk factor for significant improvement in VDM.CONCLUSION:YAG laser vitreolysis is an effective and secure treatment for PVD-type VDM,and patients of advanced age are more likely to get favorable outcomes.

The new technical progress of hot dip galvanizing process without sink roll

In this paper,the recent state and problems of the sink roll in CGL are described.Several methods of increasing its operational life span are introduced,such as surface coating technology and sleeve material technology.Fundamentally they cannot solve the problems of surface quality caused by the contact between strip and roll.On this basis,the newly developed principle and solutions for hot dip galvanizing technology without sink roll are highly emphasized,they are Float Technology,Electromagnetic pump technology,Electromagnetic enclosed slot by high-frequency AC,Electromagnetic enclosed slot by high-frequency DC.A comparison among their functions and characteristics is made and the possibility of its application is also discussed.Finally it comes to a conclusion that electromagnetic enclosed slot represents the direction of a continuous hot-dip galvanizing steel strip in the the 21st century.It has a very broad application prospects.Baosteel Technology Center is focused on the research and development of this technology.As technology advances,industrial applications is possible.

Design Considerations on a Flexible Membrane Tsunami Flood Barrier

Temporary high water floods may cause considerable damage. Protection against such flooding may be achieved with high dikes or walls. However, such rigid permanent structures may spoil the local architectures and views and may be quite expensive. Temporary collapsible structures do not have such disadvantages. This paper proposes such a temporary structure, consisting of a strong membrane made out of strong UHMWPE fibers (Dyneema?), a floating body and mooring cables. A two dimensional calculation scheme is presented and the calculation results are used for design considerations regarding the approximation of optimal configurations.

Time-domain floater stress analysis for a floating wind turbine

There are increasing focuses on developing cost-effective floating wind turbines,for which efficient stress analysis methods are needed for floater structural design.Most of the today’s studies focus on global analysis methods in which the floater is assumed as a rigid body or multiple rigid bodies and the stress distributions in the floater cannot be directly obtained.As part of the COWI Fonden funded EMULF project,a summary about the methodology,the numerical modeling procedure and the verification for stress response analysis of a semi-submersible floater for a 15MW wind turbine is presented.This analy-sis procedure includes the regeneration of the hydrodynamic pressure loads on the external wet surface of the floater due to wave diffraction,radiation and hydrostatic pressure change,and the application of these pressure loads,together with the time-varying gravity due motions,the inertial loads and the forces/moments at the boundaries(i.e.tower bottom and mooring line fairleads)of the floater to obtain the deformation and the stresses of the floater in the time domain.The analysis procedure is imple-mented in a developed MATLAB code and the DNV software package.The importance of the different hydrodynamic pressure components was discussed considering representative sea states.A verification of the obtained stress time series and statistics using this method against the regeneration from a linear frequency-domain approach was made considering irregular wave actions only,and a very good agree-ment was obtained.The developed methodology can provide an efficient solution for structural design analysis of floating wind turbines.