The effect of pollutional haze on pulmonary function

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.     

Pollutional haze as a potential cause of lung cancer

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.     

Air pollution and COPD in China

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.     

丝裂霉素C与近视眼受术者LASEK术后并发症的相关性

目的:探讨准分子激光上皮下角膜磨镶术(laser-assisted subepithelial keratomileusis,LASEK)治疗近视中应用0.2g/L丝裂霉素C(0.2g/L mitomycin C,MMC)与术后并发症,尤其与角膜上皮下雾状混浊(Haze)的相关性。方法:将我院2a期间接受LASEK术的受术者资料193例根据术式不同分为常规组92例(184眼)和MMC组101例(199眼)。采用统计学方法统计术后两组Haze发生率及其它并发症发生率,并对相关数据进行比较分析。术后随访期均为12mo。结果:两组均无Ⅱ级以上Haze的发生。两组屈光度为-6.00~-8.00DS时Ⅱ级Haze,≥-8.00DS时Ⅰ级Haze及Ⅱ级Haze的发生率比较,差异均有统计学意义(P<0.05)。其他并发症比较无统计学差异。结论:0.2g/L MMC可减少LASEK术后Haze的形成,尤其对高度近视受术者作用更加明显,并且无明显上皮毒性。     

丝裂霉素C用于不同屈光度LASEK术中的对比研究

目的探讨丝裂霉素C（MMC）对不同屈光度准分子激光上皮瓣下角膜磨镶术（LASEK）后角膜上皮下雾状浑浊（haze）与屈光回退的影响。方法将接受LASEK手术者先根据屈光度分为低、中、高度组,再将各组分为LASEK组和LASEK联合MMC组。低、中、高度LASEK联合MMC组在激光切削完毕后用浸有0.02%MMC的绵片覆于角膜切削区,时间分别为20～25s、40～50s、60～80s。术后早期观察眼部刺激症状及角膜上皮愈合情况;1、3、6、12个月复查视力、角膜haze及角膜地形图。结果 （1）术后疼痛反应、角膜上皮愈合时间低、中、高度的LASEK组与LASEK联合MMC组无显著性差异（P〉0.05）;（2）术后1、3、6、12个月,haze发生率低度近视LASEK组与LASEK联合MMC无显著性差异,中、高度近视LASEK联合MMC组haze发生率低于LASEK组（P〈0.05）;（3）低、中、高度近视LASEK联合MMC组角膜曲率术后1a与1个月相比,差别无统计学意义（P〉0.05）,高度近视LASEK组角膜曲率术后1a与1个月相比差异有统计学意义（P〈0.05）;（4）术后1a低、中近视LASEK联合MMC组与LASEK组达最佳矫正视力者差异无统计学意义（P〉0.05）,但高度近视LASEK联合MMC组达最佳矫正视力的眼数多于LASEK组（P〈0.05）。结论 LASEK术中MMC敷贴合适时间可以降低术后haze及屈光回退的发生率,高度近视组尤为显著;术前屈光度越高,所需MMC敷贴时间越长。     

济宁市市区居民PM2.5相关知识知晓情况调查

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。     

高度近视行Trans-PRK术中联合MMC对术后haze的影响

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。     

PRK术后角膜上皮下雾状混浊的相关因素分析

为探讨准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）后角膜上皮下雾状混浊（ｈａｚｅ）的原因及影响因素，对ＰＲＫ后６个月时屈光度在－１．００～－１８．５０Ｄ的３１６例（６１５只眼）近视眼的ｈａｚｅ相关因素进行观察和比较。结果：ＰＲＫ后６个月时ｈａｚｅ发生率为４４．７％，１级或以上ｈａｚｅ为１３．３％。ｈａｚｅ的发生率及密度随屈光度增高而增加（Ｐ＜０．０００１），也随切削深度的增加而增加（Ｐ＜０．０００１），术前非接触眼压超过１８ｍｍＨｇ者，ｈａｚｅ的发生率和密度增加（Ｐ＜０．００５），男性较易发生ｈａｚｅ（Ｐ＝０．０００１），与年龄呈负相关（Ｐ＜０．０５）。而角膜厚度、术前戴用接触镜及散光对ｈａｚｅ的影响不显著。结论：高度近视（＞－６．０Ｄ）和过深的切削（＞８０μｍ）是引起ｈａｚｅ的主要原因。术前眼压偏高、年龄偏低对ｈａｚｅ也有明显影响。对ＰＲＫ治疗高度近视应持审     

Effect of corneal light scatter on vision: a review of the literature

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.