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A certain delay jitter will impact the time synchronization accuracy of PTP system in the IP packet switched network. Look the network delay jitters as independently distributed random noise, and use the Least Mean Square (LMS) filter to filter out the noise, that will help to relieve the delay jitter on the system synchronization accuracy. The simulation results show that, by using the LMS algorithm, the research can increase the synchronization accuracy and decrease the bad impact on master and slave time synchronization of packet delay jitter.

To explore the cataract surgical rate (CSR) of Shanghai from 2006 to 2012 and examine its influencing factors.As of 2003, a cataract surgery registration form had been filled by physicians after every cataract surgery in Shanghai. The local eye disease prevention team then entered the relevant information into the Shanghai Cataract Operations Database. Based upon this database, CSR of Shanghai was calculated. And the number of cataract surgeries was compared between Shanghai urban and suburban districts as well as among different medical institutions.The overall CSR in Shanghai increased from 1741 in 2006 to 2313 in 2012. In 2012, CSR in urban districts reached 6013 while it stood at 460 and 584 in inner and outer suburb districts respectively. The number of hospitals performing cataract surgery in urban districts was much more than that in suburbs. And the average number of cataract surgeries per hospital per year in suburbs was only one third of that (748 cases) in urban areas. The number of cataract surgeries at in private hospitals increased rapidly during the past 7 years. The number of 1921 cases was nearly twice as many as that at tertiary hospitals in 2012. Phacoemulsification surgery was the most popular surgical choice for cataract removal, accounting for 98.40% of total cataract surgeries in 2012.Until 2012, CSR in Shanghai dropped below the target of World Health Organization (WHO). A low level of CSR in suburbs is a major influencing factor for the overall level of CSR in Shanghai.

To detect the correlation of retinal sensitivity, visual acuity and central macular thickness in patients with different types of diabetic macular edema (DME), macular function were evaluated by measuring the sensitivity, fixation pattern of the macular was examined by fundus-related microperimetry, then analyzed and compared the results with best-corrected visual acuity (BCVA) and foveal retinal thickness measured by optical coherence tomography (OCT).A retrospective case-series study. In a prospective, observational case series study, 52 consecutive patients (83 eyes) with diabetic macular edema were included.Sex, age,BMI, education, type of DM, duration, treatment, laboratory examinations, history of cardiovascular disease, hypertension, hyperlipidemia, diabetic nephropathy, and cigarette use were documented.Logarithm of the minimum angle of resolution (logMAR) BCVA was evaluated using the international vision test chart.Foveal thickness was measured by OCT. Mean retinal sensitivities, fixation stability and position was investigated with microperimetry. Variables related with BCVA, foveal thickness and mean retinal sensitivities were analyzed in different types of DME patients using one-way ANOVA or Kruskal-Wallis test. As for fixation, Fisher exact test was chosen. Pearson Correlation analysis was performed to evaluate the association between these variables. Spearman correlation analysis was used for ordinal data. The correlation between retinal sensitivities and all the variables examined were analyzed under multiple regression analysis.Eighty-three eyes were included in this study. Forty-seven eyes (56.63%) were graded as focal DME, 20 eyes (24.10%) as diffuse DME, 5 eyes (6.02%) as ischemic DME and 11 eyes (13.25%) as proliferative DME. Comparison between different types of DME patients showed statistically significant difference in mean logMAR BCVA (F = 12.737, P0.01) , mean OCT foveal thickness (H = 31.504, P0.01) , mean central retinal sensitivities (F = 14.760, P0.01) , and patterns of fixation, which were also statistically correlated (χ(2)= 23.47, 21.01; P0.01). It was a positive correlation between OCT foveal thickness and logMAR BCVA in patients with focal, diffuse and ischemic DME (r = 0.56, -0.62; P0.01) , but not with proliferative DME (r = 0.43, P = 0.19) .While central retinal sensitivities were also negative correlation between OCT foveal thickness and logMAR BCVA (r = -0.62, -0.68; P0.01) . Multiple regression analysis showed that central retinal sensitivity was inversely correlated with LogMAR and retinal thickness (t = -5.52, -4.24; P0.01).There are statistically significant difference in macular morphology and vision function between different types of DME patients. The progression of DME are expressed gradually from focal, diffuse to ischemic type. DME could be fully evaluated by measuring macular sensitivity, fixation pattern with microperimetry as well as macular thickness measurement with OCT and visual acuity determination comprehensively.

Different diagnostic and grading systems of conjunctivochalasis have resulted in apparent disparity between the prevalence rates of recent population-based studies. This study aimed to investigate the disparity between 4-level system cited from Meller and Tseng in 1998 (abbreviated here as Meller's system) and 5-level system modified from Meller's system cited from Zhang and associates (abbreviated here as Zhang's system) regarding the diagnosis and the patients' preferences for the treatment of conjunctivochalasis in the general population.A total of 546 senile residents living in the Guiyangyuan community of Shanghai, China, participated in the study. The diagnostic criteria for conjunctivochalasis were based on two diagnostic grading systems: Meller's system and Zhang's system, which was modified from Meller's system. The participants' preference regarding medical treatment for conjunctivochalasis was determined according to the response to a question. One year later, a follow-up interview determines whether the patient had undergone surgery for conjunctivochalasis.With Meller's system, 398 participants were confirmed as having conjunctivochalasis, and the prevalence rate was 72.89%. According to Zhang's system, only 213 participants were diagnosed as having conjunctivochalasis, and the prevalence rate was 39.01%. A total of 109 eyes underwent medical treatment or surgery for conjunctivochalasis in the following year, including eight eyes that were diagnosed as grade II and 101 eyes that were diagnosed as grade III according to Meller's system and five eyes that were diagnosed as grade I, 55 eyes that were diagnosed as grade II, 31 eyes that were diagnosed as grade III, and 18 eyes that were diagnosed as grade IV according to Zhang' system.Diagnoses of conjunctivochalasis using Zhang's system are more consistent with patient requests and the medical treatment strategies used than diagnoses made using Meller's system.

The control of blindness in children is a high priority within the VISION 2020 initiative. To determine the causes of severe visual impairment and blindness in children from Shanghai Blind Children School (SBCS) can provide useful information on childhood blindness in Shanghai.A cross-sectional investigation of students in SBCS was conducted in May 2010. The World Health Organization/Prevention of Blindness (WHO/PBL) eye examination record system for children with low vision and blindness was used. The results were further compared with the findings of two previous investigation studies conducted in 1986 and 2004, respectively in SBCS.Of the 146 children observed, 80 children (54.8%) were blind (best corrected best visual acuity less than 0.05), 27 children (18.5%) had severe visual impairment (best corrected visual acuity less than 0.1 but better than or equal to 0.05), and 34 children (23.3%) had moderate visual impairment (best corrected visual acuity less than 0.3 but better than or equal to 0.1). The major affected anatomic sites in the 107 children with severe visual impairment and blindness (SVI/BL) were retina (47.7%), whole globe (16.8%), optic nerve (13.1%) and lens (9.3%). The leading causes of SVI/BL were retinopathy of prematurity (ROP, 25.2%), followed by retinal dystrophy (15.9%), optic nerve atrophy (9.3%) and microphthalmos (9.3%). The two leading etiologic categories of SVI/BL were perinatal/neonatal (36.4%) and congenital/hereditary groups (29.0%). The leading cause of moderate visual impairment was aphakia after cataract surgery (congenital cataract, 44.1%). Compared with the findings in two previous investigations in SBCS, the proportion of ROP in visual impairing diseases increased, while the proportion of disorders of the lens (cataract and aphakia) significantly decreased.The leading cause of childhood blindness in SBCS nowadays is ROP. It is projected that without improvement in perinatal medical care that ROP will continue to be a major cause of childhood blindness.

Vision check is the first step of mass screening works of most blinding diseases. In recent China, the primary childhood vision check is mainly conducted by hygiene teachers in educational institutions, following the Chinese traditional poor vision classification system, which is based on uncorrected distance visual acuity. However, this classification system does not meet childhood vision developmental mechanism, and may lead to massive unnecessary repetitive screening, diagnosis and treatment of corrected ametropia. In some Chinese communities and villages, the vision check is still based on uncorrected distance visual acuity during eye diseases mass screening procedures in adults. The critical point of preschool children vision impairment screening is then suggested to follow novel Chinese amblyopia diagnostic criteria. Combination of uncorrected, presenting and corrected visual acuity indexes may be used for children' vision check. Collaboration of children health care workers, pediatric ophthalmologists and optometrists in children eye diseases screening projects should be realized as soon as possible. In the adult population, presenting vision is suggested to be used in vision impairment screening works, and appropriate vision check scheme should be adopted in specific eye diseases screening works.

To investigate the prevalence of blindness and low vision and the leading causes of blindness in residents aged≥60 years in Dachang Blocks of Baoshan District, Shanghai, China.A cross-sectional study was carried out by Shanghai Eye Disease PreventionTreatment Center and the Center for Disease Control and Prevention in Baoshan District of Shanghai from October to December in 2009. Randomly cluster sampling was used to identify the adults aged≥60 years who had lived in Dachang Blocks of Baoshan District, Shanghai for more than 10 years. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) based on autorefraction and subjective refraction were measured separately in each eye. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using slit lamp-microscopes direct ophthalmoscopy and non-mydriatic digital camera. And the leading causes of visual impairment were assured. The Chi square test was used between the groups of rate comparison.Of 5199 enumerated subjects≥60 years of age, 87.42% (4545/5199) were examined. All subjects were urban population who were originally changed from the rural population in nearly 10 years. In this population, with best-corrected visual acuity, 30 persons were diagnosed as blindness, 145 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.67%, 3.19%, respectively. Low vision was associated with female gender. It was statistically significant difference (χ2=4.88, P0.05). The leading causes of blindness were cataract, macular degeneration, ocular absence or atrophy, glaucoma, and diabetic retinopathy or corneal diseases. With presenting visual acuity, 39 persons were diagnosed as blindness, 401 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.86%, 8.82%, respectively. Blindness and low vision were associated with older age. The prevalence of blindness and low vision increased rapidly in aged 75 years or older people. The leading causes of blindness were cataract, uncorrected refractive error, macular degeneration, ocular absence or atrophy, glaucoma. Low vision was associated with female gender. It had statistically significant difference (χ2=13.345, P0.01).In rapidly urbanized and aging community of Shanghai, cataract, uncorrected refractive error, macular degeneration were the leading causes of blindness with presenting visual acuity. The prevalence of low vision in females was higher than that of males which had statistically significant difference. These kinds of residents needed more targeted eye health education and services.

To assess the standardization of meta-analyses reports on eye diseases published in Chinese journals in recent ten years.Meta-analyses manuscripts on eye diseases published in Chinese-language journals from January 2000 to September 2010 were retrieved through the following databases: Wanfang Data, VIP Information, CNKI and Chinese Bio-medicine Database, along with manual database search. The manuscripts translated from foreign-language meta-analyses reports or repetitive publications were excluded. All enrolled manuscripts were then analyzed item by item according to the checklist of QUOROM statement and MOOSE guidelines.50 manuscripts were finally enrolled into the present quality appraisal study, including 32 meta-analyses manuscripts of randomized control trail (RCT) studies and the other 18 meta-analyses manuscripts of observational studies. Out of the 32 manuscripts evaluated with QUOROM statement, only 8 (25.0%) manuscripts included flow chat describing the process of selection, 18 (56.3%) manuscripts included sensitivity analyses and 9 (28.1%) included bias evaluation part. Out of the 18 manuscripts evaluated with MOOSE guidelines, only 6 (33.3%) included comprehensive relative literatures search strategy, 4 (22.2%) included sensitivity analyses and 8 (44.4%) included bias evaluation section.The standardization of meta-analyses reports on eye diseases published in Chinese journals needs to be improved.

It was well known that tangential vitreoretinal traction and epiretinal membrane play important roles during the formation of macular hole (MH) associated with retinal detachment (RD) in highly myopic eyes. But it was not clear about the correlations between anteroposterior traction, posterior vitreous cortex (PVC) and MH-RD. The vitreous status in highly myopic eyes were analyzed to explore the effect of PVC in the role of MH-RD formation.Sixteen consecutive highly myopic eyes with RD due to MH were retrospectively analyzed from January 2009 to April 2009. The preoperative examinations for detecting posterior vitreous detachment (PVD) and vitreoretinal traction included B-mode ultrasonography and optical coherence tomography (OCT). The residual PVC and PVD were confirmed intraoperatively during triamcinolone acetonide (TA) assisted vitrectomy.Under ultrasonography, the preoperative PVD patterns were stratified as: complete PVD in three (19%) eyes, partial PVD in eight (50%) eyes, and no PVD in five (31%) eyes. OCT confirmed vitreoretinal traction and no complete PVD in 10 (63%) eyes, including anteroposterior traction in four eyes and tangential traction in six eyes. During TA-assisted vitrectomy, it was confirmed that no complete PVD existed in 16 eyes, including six eyes (38%) finally diagnosed of partial PVD, and five (31%) eyes with vitreoschisis. Anteroposterior vitreoretinal traction around MH is always in conjunction with partial PVD (67%), and high proportion (80%) of vitreoschisis is associated with tangential vitreoretinal traction. Comparing with the precision of TA staining of PVD diagnosis, the coincidence rate of ultrasonography was 69% (P = 0.02), and that of OCT was 63% (P0.01).The residual PVC due to partial PVD or vitreoschisis may cause the anteroposterior or tangential traction of macular area, which contributes to the formation of MH and subsequent RD in highly myopic eyes. And it is necessary to realize the vitreoretinal relationship and assess the status of PVC synthetically for surgery by combined ultrasonography and OCT preoperatively and TA staining intraoperatively.

The present paper concerns on some distinct shortcomings of recent eye diseases related meta-analysis manuscripts in Chinese literatures, then discusses the following important-aspects in meta-analysis procedures: addressing the purpose properly, providing a precise title, collecting relative literatures comprehensively, assessing the quality of enrolled studies systematically, evaluating the result of test for heterogeneity correctly, choosing the outcome indicators and effect indexes accurately, analyzing sensitivity, and correlating the statistical and clinical significance of the results in an objective manner, et al. The reporting format is suggested to follow the MOOSE guidelines and QUOROM statement.

To design the community-based tele-screening system for diabetic retinopathy and evaluate the feasibility of it.Cross-sectional study. The tele-screening system was based on non-mydriatic digital eye fundus camara photography and computer network technology. 109 type 2 diabetes mellitus residents were randomly selected for system evaluation, which included: (1) The consistency of the far visual acuity examined by an ophthalmologist and a trained inspector, evaluated by paired t-sample test; the consistency of diagnosis of diabetic retinopathy by tele-screening system and traditional screening method by ophthalmoscope, slit-lamp bimicroscope combined with non-contact lens after pupil dilation, evaluated by kappa value and intraclass coefficient correlation. (2) The proper compression ratio of the fundus photographs transferring through the internet, evaluated by intraclass coefficient correlation. (3) The working time for the tele-screening on the residents, comparing with the traditional screening method.The visual acuities of the 218 eyes in 109 residents examined by an ophthalmologist were0.05 in 13 eyes, between 0.05 and 0.3 in 61 eyes,or = 0.3 in 144 eyes. No significant difference was found between the vision acuity given by different examiner (t = -0.572, P = 0.568). 52 eyes were diagnosed as DR by traditional screening method, while 51 eyes were diagnosed as DR by the tele-screening method, so in DR diagnosis, high consistency were found with kappa value as 0.885, 95%CI 0.807 to 0.963, and in DR degree diagnosis with ICC value as 0.91, 95%CI 0.85 to 0.94. The most compression ratio of fundus photographs was as low as 15% (526 x 350). It took 5 to 7 minutes for the tele-screening system to examining and giving diagnosis of a diabetes mellitus resident, a little bit sooner than traditional screening method.This community-based tele-screening system can meet the requirements of mass screening for diabetic retinopathy.

The present paper concerns on some shortcoming of the planning and conducting steps in recent Chinese vision-related quality of life (VRQoL) studies, addresses the main application of VRQoL, introduces two instruments, these are questionnaire and utility value for VRQoL evaluation, the standard strategies for introducing or self-making questionnaire, and the principals of the conducting work.

To investigate the prevalence rate of blindness and low vision and the leading cause of blindness in residents agedor = 60 years in Beixinjing blocks, Shanghai.A cross-sectional study was carried out by Shanghai First People's Hospital, affiliated Shanghai Jiaotong University and Shanghai Beixinjing Community hospital from November 2007 to April 2008. Randomly cluster sampling method was used, and all the individuals agedor = 60 years in 8 communities from Beixinjing blocks, Shanghai was enrolled in this study. The pinhole visual acuity and presenting visual acuity were measured separately in each eye. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using slit lamp-microscopes, direct ophthalmoscopy and non-mydriatic digital camara. Assigned ophthalmologic doctors assured the leading blind causes of every blind person. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out.3851 individuals were examined, and the response rate was 92.73%. According to WHO diagnostic criteria: 29 persons were diagnosed as blindness, 11 male (37.93%) and 18 female (62.07%). 104 persons were diagnosed as low vision, 37 male (35.58%) and 67 female (64.42%). The prevalence rates of blindness and low vision were 0.75% and 2.70%. The leading causes of blindness were macular degeneration, cataract, corneal diseases, and retinal detachment. According to presenting vision diagnostic criteria: 61 persons were diagnosed as severe binocular blindness, 20 male (32.79%) and 41 female (67.21%). 66 persons were diagnosed as slight binocular blindness, 27 male (40.91%) and 39 female (59.09%). 276 persons were diagnosed as monocular blindness, 120 male (43.48%) and 156 female (56.52%). The prevalence of severe binocular blindness, slight binocular blindness and monocular blindness was 1.58%, 1.71% and 7.17%, respectively. The leading causes of blindness were macular degeneration, cataract, ametropia and corneal diseases.The leading cause of blindness was macular degeneration. The prevalence of degenerative retinopathy in this area is on the rise.

To investigate the prevalence and relative factors of conjunctivochalasis among people over 60 years old in Caoyangxincun community of Shanghai.A cross-sectional study based on local residents in this community was carried out from September 2008 to October 2008. Cluster sampling was used in randomly selecting individuals agedor = 60 years. Slit-lamp ophthalmoscope was used for eye examination and diagnosis. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. A database was set using SPSS 10.0 software, Chi-square test was used for data analysis.2110 residents took part in this study, with the response rate 94.85%. 930 cases (1762 eyes) were confirmed as conjunctivochalasis, so the prevalence rate is 44.08%. The prevalence of conjunctivochalasis was increasing with age (chi(2) = 10.44, P0.01). 556 cases (943 eyes) were confirmed as degree I, 246 cases (647 eyes) as degree II, 120 cases (162 eyes) as degree III and the rest 8 cases (10 eyes) as degree IV. Several symptoms, such as blurred vision, asthenopia and eye pain were more frequent in patient group than in the normal ones (chi(2) value was 15.44, 20.54 and 19.74, respectively, P0.01). In the disease eyes, the conjunctiva usually piled up on the nasal and temporal side (944 eyes, 53.58%), the location of inferior lid margin was usually above corneal limbus (2589 eyes, 61.35%) and inferior lid margin entropion and introversion were always found (7.04% and 6.63%). Abnormal lacrimal river was found in 87.23% of the diseased eyes, more than the non-conjunctivochalasis eyes (chi(2) = 1615.81, P0.01).Conjunctivochalasis is a common eye disease in aged population, with obvious signs and symptoms of ocular surface and lacrimal river impairment. In the local residents, most patients were classified as minimal or moderate degree. The location of inferior lid margin and the tension of inferior lid may be related factor of conjunctivochalasis.

To investigate the prevalence of dry eye in populations equal or over 20 years old in Jiangning District, Shanghai, China.This was a cross-sectional study. From September 2008 to January 2009, 6 small districts including 21,102 people of Jiangning District were randomly selected as survey venues by Department of Ophthalmology in First People's Hospital affiliated to Shanghai Jiaotong University. Then, 1266 people as the selected residents were enrolled, which was figured out through the random cluster sampling procedure. Every participant completed dry eye questionnaire, the ocular surface disease index (OSDI), and a series of examination including slit-lamp microscope, tear-film break-up time (BUT) , Schirmer I test, and fluorescein staining of the cornea (F1). The diagnosis of dry eye was referred to the well-accepted domestic diagnostic criteria The SPSS11. 0 software was used to analyze the database, t . test, chi2 test, one-way-ANOVA and Logistic regression were used for analysis.One thousand and eighty five residents finally took part in this study, and the inclusion ratio was 85.70%. Three hundred and twenty six individuals, including 101 men and 225 women, were diagnosed as dry eye, and the prevalence rate was 30.05%. The prevalence of dry eye in the female (33.78%) was higher than that of the male (24.11%) (chi2 = 11.46, P0.01). The prevalence of dry eye in people over 50 years old was higher than that under 50 years (chi2 = 94.50, P0.01). The figure of Schirmer I test and BUT decreased in elder people, at the same time the scores of Fl and MGD increased. Meanwhile, the score of OSDI in dry eye patients was significantly higher than that in non-dry eye individuals. The relative risk factors of dry eye were gender, age, wearing contact lens, long-time using of eye solutions, taking anti-allergy drugs.The prevalence of dry eye in female is higher than that in the male. And the prevalence of dry eye increases following the aging process. Relative risk factors of dry eye are gender, age, wearing contact lens, long-time using of eye solutions, taking anti-allergy drugs.

Nowadays, the number of ophthalmic population-based epidemiology survey is increasing in China But some distinct shortcomings of the planning and conducting steps, such as wrong concept of the relationship between statistic correlation and risk factor, unnecessary large sample size, inappropriate sampling method, informal design of questionnaire, no pilot study, improper field study, incorrect data input and sort, no quality control, etc., are presented in some surveys, resulting in the poor reliability. Valuable epidemiology results could be obtained only after elucidation of these problems and using a standard design.

To investigate the prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME) in Beixinjing District, and analyze the image characteristics of their Optical coherence tomography (OCT), so as to evaluate the correlation among DME and the grade of DR as well as posterior vitreous detachment (PVD).In a prospective study, OCT was performed in 151 eyes of 100 type 2 diabetes patients with DR and 102 normal eyes as control subjects.795 cases were examined, and 215 of them were diagnosed to have DR. The average thickness of macular fovea was 195.56 microm in 151 eyes from 100 random sampling. 46 eyes had macular thickening. Three characteristics were found in the images of OCT in the patients with DME: sponge-like retinal swelling in 35 eyes (76.1%), macular cystoid edema in 8 eyes (17.4%), and serous retinal detachment in 3 eyes (6.5%). The statistical analysis showed that there was a positive correlation between the thickness of macular fovea and negative correlation with best-corrected visual acuity (r = 0.2869, P = 0.0004). There was statistic significance between the severity of DR and DME (P = 0.0003). But there was no statistic significance between DME and PVD.The prevalence of DME is 37.1% in this district. Three type images of OCT were demonstrated in DME. The macular thickness is correlated with the severity of DR regardless of PVD.

To investigate the prevalence of age-related maculopathy (AMD) in Shanghai residents older than 50 years.1023 individuals were examined in the years 2002 and 2003 for clinical and subjective signs of dry and exudative AMD. A interview concerning clinical symptoms of AMD as also a complete eye exam was performed. Non-mydriatic retinoscopy was done by use of a direct opthalmoscopy. Fundus photography was used to confirm and document the diagnosis. The diagnosis of both forms of AMD was made according to the criteria of the Sub-society of Fundus Disease, Chinese Ophthalmological Society.15.5% of the included population had AMD and 19 of them were exudative AMD. The prevalences of AMD in the age groups of 50-59, 60-69, 70-79 and more than 80 were identified as 5.7%, 13.5%, 20.2% and 23.5%, respectively (chi(2) = 27.97, P0.01). No statistical differences were found concerning atrophic and exudative AMD related to gender, education, daily focus time, smoking, alcohol consumption and systematic diseases. In the AMD patients, 5.1% and 36.2% of the eyes were identified as blind or with low vision. In exudative AMD patients, 23.3% and 63.3% of the eyes were identified as blind or with low vision. The visual acuity of eyes with exudative AMD was significantly lower than the visual acuity of atrophic AMD eyes. (chi(2) = 15.4, P0.01).The prevalence of AMD is high, and increasing with aging. The AMD, especially the exudative AMD, leads to severe visual impairment.