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1.
The cornea is the transparent connective tissue window at the front of the eye. The physiological role of the cornea is to conduct external light into the eye, focus it, together with the lens, onto the retina, and to provide rigidity to the entire eyeball. Therefore, good vision requires maintenance of the transparency and proper refractive shape of the cornea. The surface structures irregularities can be associated with wavefront aberrations and scattering errors. Light scattering in the human cornea causes a reduction of visual quality. In fact, the cornea must be transparent and maintain a smooth and stable curvature since it contributes to the major part of the focusing power of the eye. In most cases, a simple examination of visual acuity cannot demonstrate the reduction of visual quality secondary light scattering. In fact, clinical techniques for examining the human cornea in vivo have greatly expanded over the last few decades. The measurement of corneal back scattering qualifies the degree of corneal transparency. The measurement of corneal forward-scattering quantifies the amount of visual impairment that is produced by the alteration of transparency. The aim of this study was to review scattering in the human cornea and methods of measuring it.  相似文献   
2.
Along with fast economic growth over the past few decades, the world is faced with cumulatively serious environmental pollution and now is paying increased attention to pollutional haze. In the last few years, multiple epidemiological studies and animal models have provided compelling evidences that inhalation of pollutional haze could be linked to several adverse health effects. Since the respiratory tract is the crucial passageway of entry of pollutional haze, the lung is the main affected organ. Therefore, here, we reviewed some of the important information around long-term exposure to pollutional haze and lung cancer, as well as highlight important roles of pollutional haze in human lung carcinogenesis, providing evidence for pollutional haze acting as another risk factor for lung cancer.  相似文献   
3.
Detrimental health effects of atmospheric exposure to ambient particulate matter (PM) have been investigated in numerous studies. Exposure to pollutional haze, the carrier of air pollutants such as PM and nitrogen dioxide (NO2) has been linked to lung and cardiovascular disease, resulting increases in both hospital admissions and mortality. This review focuses on the constituents of pollutional haze and its effects on pulmonary function. The article presents the available information and seeks to correlate pollutional haze and pulmonary function.  相似文献   
4.
Recently, many researchers paid more attentions to the association between air pollution and chronic obstructive pulmonary disease (COPD). Haze, a severe form of outdoor air pollution, affected most parts of northern and eastern China in the past winter. In China, studies have been performed to evaluate the impact of outdoor air pollution and biomass smoke exposure on COPD; and most studies have focused on the role of air pollution in acutely triggering symptoms and exacerbations. Few studies have examined the role of air pollution in inducing pathophysiological changes that characterise COPD. Evidence showed that outdoor air pollution affects lung function in both children and adults and triggers exacerbations of COPD symptoms. Hence outdoor air pollution may be considered a risk factor for COPD mortality. However, evidence to date has been suggestive (not conclusive) that chronic exposure to outdoor air pollution increases the prevalence and incidence of COPD. Cross-sectional studies showed biomass smoke exposure is a risk factor for COPD. A long-term retrospective study and a long-term prospective cohort study showed that biomass smoke exposure reductions were associated with a reduced decline in forced expiratory volume in 1 second (FEV1) and with a decreased risk of COPD. To fully understand the effect of air pollution on COPD, we recommend future studies with longer follow-up periods, more standardized definitions of COPD and more refined and source-specific exposure assessments.  相似文献   
5.
目的: 观察丝裂霉素C(mitomycin C, MMC)辅助准分子激光角膜切削术(PRK)的疗效及并发症分析。

方法:回顾性临床病例研究。随机选择2009年40例80眼实施PRK治疗近视的患者作为常规组,2010年PRK术中应用0.2g/L MMC 20s的40例80眼作为MMC组。术后7d; 1,3,6,12mo观察裸眼视力、屈光状态以及角膜上皮愈合、发生糜烂、角膜干燥和haze情况,两组数据进行对比分析。

结果:术后12mo随访期间,两组裸眼视力、术后等效球镜、角膜上皮愈合及干眼情况差异无统计学意义。常规组有2眼,MMC组有9眼发生角膜糜烂伴丝状角膜炎,两组差异有统计学意义(Pearson χ2=4.783,P<0.05)。全部病例均治愈,没有复发病例。常规组、MMC组术后1,3,6,12mo haze的发生率分别为26%,6%,2%,0和44%,25%,10%,2%,术后1mo(Pearson χ2=5.385,P<0.05)、3mo(Pearson χ2=10.667,P=0.001)差异有统计学意义。

结论:PRK术中使用0.2g/L MMC可以减少术后haze的发生。MMC对PRK术中保留的角膜上皮的影响可能是术后角膜糜烂发生的原因之一,术中要避免接触到治疗区外保留的正常角膜上皮。  相似文献   

6.
目的:评价经上皮准分子激光角膜切削术(Trans-PRK)联合0.02%丝裂霉素C(MMC)治疗高度近视预防角膜上皮下雾状混浊(haze)的临床效果。

方法:回顾性病例分析。收集我院2016-01/2017-12行Trans-PRK手术治疗的高度近视患者89例142眼,其中94眼联合使用0.02% MMC设为MMC组,MMC的使用时间为30~45s; 48眼未使用MMC设为对照组。两组患者术后均规律使用类固醇激素滴眼液治疗4mo,随访6mo。采用树模型分析探讨不同相关因素与haze发生的相关性。

结果:按照Fantes分级进行haze评估。MMC组术后haze发生率为8.5%(8/94),对照组为33.3%(16/48)(P=0.001)。树模型结果显示,切削光区直径和切削深度是haze发生的主要相关因素(P<0.01)。当切削光区直径≤5.6mm时发生haze的可能性越大,当切削光区直径>5.6mm时,最大切削深度成为haze发生的主要影响因素。

结论:对于薄角膜及角膜形态异常的高度近视患者,在选择Trans-PRK治疗时应考虑切削光区直径及切削深度,同时应联合使用0.02% MMC,可以安全有效地减少haze发生。  相似文献   

7.
目的分析济宁市居民对PM2.5相关知识知晓情况,为政府以及相关部门制定科学合理的政策及措施提供科学依据。方法 2013年4月对400名调查对象进行问卷调查。调查居民对PM2.5的主要来源、化学成分、健康危害等的认知情况,对空气质量的关注程度,济宁雾霾天气的好发季节,在雾霾天气时所采取的防护措施以及对如何有效减少雾霾天气的建议和意见。根据数据类型采用统计描述、t检验、单因素方差分析等统计学方法,P0.05为差异有统计学意义。结果发放问卷400份,实际收回369份,有效问卷369份,回收率为92.3%。被调查的369名居民中,关于PM2.5主要来源完全了解的70名,占19.0%;非常了解的107名,占29.0%;一般了解的163名,占44.2%;完全不了解的29名,占7.8%。关于化学成分完全了解的12名,占3.3%;非常了解的42名,占11.4%;一般了解的256名,占69.4%;完全不了解的59名,占15.9%。对PM2.5的健康危害认知平均得分(3.01±1.87)分。不同性别的居民对PM2.5健康危害认知得分差异无统计学意义(P0.05),不同年龄、文化程度、职业的居民对PM2.5健康危害认知的得分差异均有统计学意义(F=2.332、3.906、3.409,均P0.05)。被调查的369名居民中在雾霾天气时绝大多数人都采取了相应的防护措施,未采取任何防护措施仅42名,占11.4%。结论政府和相关部门有必要加强雾霾天气危害的宣传力度和采取相关措施,引起社会各方重视,提高居民在雾霾天气时的防护意识。  相似文献   
8.
目的:探讨在LASEK治疗中、高度近视术中使用0.2g/L丝裂霉素C预防haze的安全性和有效性。方法:将近视患者120例240眼按左、右眼分为两组,右眼为实验组,左眼为对照组,实验组在完成激光切削后,一次性使用0.2g/L丝裂霉素C液,对照组不用任何药物,术后定期随访角膜刺激症状、角膜上皮生长情况、术后视力、haze等情况。结果:术后1,3,6mo两组术后的刺激症状及角膜上皮愈合时间的差异无统计学意义(P>0.05)。在0级haze中,术后1mo实验组有105眼(87.5%),对照组有62眼(51.7%);术后3mo,实验组有80眼(66.7%),对照组有39眼(32.5%);术后6mo,实验组有96眼(80.0%),对照组有68眼(56.7%),两组差异均有统计学意义(P<0.05)。术后6mo,实验组有91眼(75.8%)的视力大于或等于1.0,对照组有51眼(42.5%)的视力大于或等于1.0,两组的差异有统计学意义(P<0.05)。结论:在LASEK术中使用0.2g/L丝裂霉素C可减轻haze的发生,且安全有效,无明显的毒副作用。  相似文献   
9.
In this study, the authors assessed air quality and health effects of the 1997 haze disaster in Indonesia. The authors measured carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen dioxide, ozone, particulate matter with diameters less than or equal to 10 μum, inorganic ions, and polycyclic aromatic hydrocarbons. The authors also interviewed 543 people and conducted lung-function tests and determined spirometric values for these individuals. Concentrations of carbon monoxide and particulate matter with diameters less than or equal to 10 μrn reached “very unhealthy” and “hazardous” levels, as defined by the Pollution Standards Index. Concentrations of the polycyclic aromatic hydrocarbons were 6–14 times higher than levels in the unaffected area. More than 90% of the respondents had respiratory symptoms, and elderly individuals suffered a serious deterioration of overall health. In multivariate analysis, the authors determined that gender, history of asthma, and frequency of wearing a mask were associated with severity of respiratory problems. The results of our study demonstrate the need for special care of the elderly and for care of those with a history of asthma. In addition, the use of a proper mask may afford protection.  相似文献   
10.
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