角膜接触镜对泪液渗透压的影响

无论是亲水性角膜接触镜还是半硬性角膜接触镜,佩戴后均会对泪液造成一定影响,镜片的移动破坏了泪液的稳定性,促使泪液过快蒸发,造成角膜接触镜相关性干眼症,配戴角膜接触镜的人群中79％有干眼症状。泪液渗透压的增高是干眼的主要诊断指标之一。     

角膜接触镜配戴时间与泪膜稳定性的相关分析

目的 观察分析配戴软性角膜接触镜的时间与泪膜破裂时间（BUT）的相关性。方法 随机对132例264眼就诊于我科有角膜接触镜配戴史的近视患者进行Lasik术前测定泪膜破裂时间（BUT）。结果 132例中，戴角膜接触镜1y以内者46例（92眼），其中8眼（8．7％）BUT≤5s，44眼（47．8％）BuT〉10s；戴角膜接触镜5y以上者42例（84眼），其中26眼（31．0％）BUT≤5s，20眼（23．8％）BUT〉10s。结论 配戴角膜接触镜时间较长（5y以上）的近视患者泪膜破裂时间（BUT）≤5秒者的比例（31．0％）明显高于戴角膜接触镜时间较短（1y内）的患者（8．7％），角膜接触镜配戴时间与泪膜稳定性呈负相关。     

泪液的研究进展

随着多种全身及眼局部药物的大量应用和角膜接触镜的普及，眼表疾病日益增多，泪液，泪膜的研究更加重要。泪液量、泪液成分的改变常是诱发眼表疾病的重要原因，而眼表疾病的诊断、治疗均应从泪液量及成分的研究着手，现就近年来在泪液分泌及排泄，泪漠稳定性，结膜印迹细胞学，泪液的免疫成分，泪液动力学等方面的研究进展作一综述。     

泪液分泌与排出动力的临床观察研究

目的:通过临床观察,证实"瞬目是基础泪液分泌、前泪膜形成更新与排出泪液共同的动力源"假说。方法:临床观察4216人次。按常规项目检查并进行以下特殊项目的询问与观察:(1)各种泪道阻塞患者60例入睡后溢泪症状。(2)30例觉醒后闭目养神状态下溢泪症状。(3)观察300例新生儿出生后瞬目和溢泪症状。(4)随意观察300人次以上各种瞬目。(5)活体观察360眼泪道逆行置管术后瞬目所产生排出泪液作用。(6)观察暴露性角膜炎者基础泪液分泌。结果:(1)各种原因导致的不同类型的所有泪道阻塞患者瞬目停止状态时溢泪症状中止。(2)观察昏迷和醒觉状态下睑裂闭合不全暴露性角膜炎者,并未出现由其他神经反射弧启动的基础泪液分泌。(3)泪道阻塞患者觉醒状态下闭目养神溢泪症状中止者26例,4例明显减轻。(4)观察新生儿:第一声哭啼有泪者接近10%,多数新生儿生后7d(最迟者出生20d)啼哭有泪,出生后都有瞬目动作。(5)活体观察泪道逆行置管术后睁眼状态引流管内水液平面下降;闭眼状态水液平面上升,幅度约2.0mm左右。(6)随机观察300人次正常人瞬目发生的频率、节律和瞬目中止与自我抑制瞬目持续时间发现下注视最慢,水平注视居中,向上三个注视最快。向下注视眼位抑制瞬目持续时间最长。结论:临床观察结果各从不同方面验证"瞬目是基础泪液分泌、前泪膜形成更新与排出泪液共同的动力源"假说。但还需要临床和实验室进一步研究,寻找更直接的验证。     

长期配戴硬性角膜接触镜对泪膜稳定性的影响

目的：探讨长期配戴硬性角膜接触镜对泪膜稳定性的影响,观察硬性角膜接触镜长期配戴的安全性。

方法：本组观察对象为2014-10/2016-01于我院进行配戴硬性角膜接触镜矫正的近视患者60例120眼以及无硬性角膜接触镜配戴史的低度近视患者30例60眼,将白天配戴RGP的患者26例52眼设为白天配戴组,只在夜间配戴OK镜的患者34例68眼设为夜间配戴组,无硬性角膜接触镜配戴史的低度近视患者30例60眼设为对照组。戴镜前、戴镜1、6mo,1、2a 进行泪液分泌试验(Schirmer I test,SⅠt)、泪膜羊齿状试验以及泪膜破裂时间(break-up time ,BUT)检测。

结果：白天配戴组与夜间配戴组戴镜后各时间点BUT、SⅠt均较戴镜前降低,且均显著低于对照组,差异有统计学意义(P<0.05),戴镜后6mo,1、2a白天配戴组BUT、SⅠt显著低于夜间配戴组,差异有统计学意义(P<0.05); 三组患者配镜前、配镜1、6mo后泪液羊齿状试验分级比较,差异无统计学意义(P>0.05); 配镜1、2a白天配戴组与夜间配戴组≥Ⅲ级眼数显著高于对照组,差异有统计学意义(P<0.05); 白天配戴组与夜间配戴组组间比较差异无统计学意义(P>0.05)。

结论：长期配戴硬性角膜接触镜可使泪液分泌量降低,泪膜稳定性下降。     

去势雄兔泪液分泌及泪膜稳定性的改变

目的观察去势后雄兔眼表及泪膜的变化,评价雄激素对泪液分泌及泪膜稳定性的影响.方法将16只雄兔随机分为去势(实验)及对照两组,每组8只.实验组分别于去势前和去势后1、2、3、4周、2及3个月行Shirmer试验、泪膜破裂时间(break-up time, BUT)及虎红染色检测;利用化学发光法检测实验组手术前、后血清睾酮水平,并行统计学分析处理.3个月后处死两组兔,取其泪腺、Harder腺、结膜、角膜及角膜缘组织行病理组织学观察.结果实验组Shirmer试验、泪膜破裂时间明显低于正常对照组,且随观察时间的延长差异有显著性(t=9.032,P＜0.01;t=4.747,P＜0.01).虎红染色实验组为阳性,对照组为阴性.实验组术后血清睾酮水平(4.52±0.81) nmol/L明显低于术前(19.76±1.53) nmol/L(t=22.290,P＜0.01).病理学观察,实验兔泪腺上皮细胞胞浆萎缩扁平,腺腔扩大,腺泡泡状黏液消失,PAS染色阳性物质减少,结膜杯状细胞数量减少,角膜上皮及角膜缘干细胞形态学上无明显改变.结论去势后雄兔睾酮水平明显低下,泪腺上皮细胞萎缩,腺泡泡状黏液物质消失及结膜杯状细胞减少,导致泪液分泌的质和量改变及泪膜稳定性降低.     

长期局部应用β-受体阻滞剂影响泪液分泌及泪膜稳定性的研究

目的　观察长期局部应用 β-受体阻滞剂对泪液分泌及泪膜稳定性的影响。方法　 1994年 1月～2 0 0 1年 8月间青光眼患者 139例。年龄 14～ 83岁 ;男 84例 ,女 5 5例 ;病程 3月～ 4年。将 139例患者分成对照组(无局部用药组 ) 6 1例和 β-受体阻滞剂组 78例 (用药组 ,使用 β-受体阻滞剂≥ 18月 ,如 0 .5 %噻吗洛尔、0 .5 %贝特舒 (贝他洛尔 ) ,观察指标包括眼异物感、干涩灼热感、畏光感、结膜充血、分泌物及干眼症三项检查 Schirmer 试验、泪膜破裂时间 (BU T)和角膜荧光素染色 )。结果　 β-受体阻滞剂组的干眼症状和体征明显 ,泪膜功能受损 ,与对照组比较差异有显著性 (P <0 .0 1) ;而两组在青光眼的类型、病程、年龄、性别等方面则差异均无显著性 (P >0 .0 5 )。结论　长期局部使用 β-受体阻滞剂可以因药物引起结膜的慢性炎症等副作用而导致泪液分泌减少和影响泪膜稳定性 ,应用人工泪液可以改善患者的干眼症状     

角膜接触镜相关性干眼与睑板腺形态变化的关系

目的:探讨软性角膜接触镜(CL)长期配戴者睑板腺形态改变与干眼观察指标的关系。方法:采用横断面研究方法,连续纳入2014年5月至2015年6月就诊于天津医科大学眼科医院拟行屈光性手术的患者157例314眼,其中长期配戴软性CL者91例182眼作为CL组,未配戴CL者66例132眼作为对照组。收集并比较2个组患者眼表疾病...     

戴软接触镜对泪膜的影响研究

目的：前瞻性设计、研究软镜配戴对泪液和泪膜的影响,以及软镜本身的脱水变化,探讨软镜配戴与干眼发生的关系。方法：８０名眼前表面健康自愿者参加该研究,检测项目有：①四种不同含水量和厚度软镜配戴的脱水变化;②软镜对泪膜形态的改变;③泪膜状况对软镜配戴后的脱水状况的影响 结果：①软镜配戴后均发生镜片脱水现象,脱水过程主要发生在第５～１０分钟,镜原含水量高,则脱有明显,镜片薄,脱水量亦高;②配戴软镜后,泪膜     

Tear film,contact lenses and tear biomarkers

This article summarises research undertaken since 1993 in the Willcox laboratory at the University of New South Wales, Sydney on the tear film, its interactions with contact lenses, and the use of tears as a source of biomarkers for ocular and non‐ocular diseases. The proteome, lipidome and glycome of tears all contribute to important aspects of the tear film, including its structure, its ability to defend the ocular surface against microbes and to help heal ocular surface injuries. The tear film interacts with contact lenses in vivo and interactions between tears and lenses can affect the biocompatibility of lenses, and may be important in mediating discomfort responses during lens wear. Suggestions are made for follow‐up research.     

Preliminary tear film measurements of tolerant and non-tolerant contact lens wearers

Background : The relationship between contact lens intolerance and tear stability, tear quantity, distribution and consistency has yet to be clearly established. In this study, we have examined the tear film of several tolerant and non-tolerant soft contact lens wearers. We aimed to develop a number of clinical and biochemical techniques to establish a correlation between one or more factors leading to contact lens intolerance. Methods : Subjects were separated by their self-described tolerance to contact lens wear. Five tolerant and five non-tolerant subjects were chosen. A McMonnies symptomatology questionnaire was used to ascertain subject history, while non-invasive tear break-up time (TBUT) examined tear stability. Basal tear collection was performed using glass capillary tubes, the tear flow rate was measured and one dimensional gel electrophoresis used to analyse protein differences. Results : Non-tolerant subjects experienced primary symptoms, such as dryness and grittiness, more often than tolerant subjects (p = 0.007). The TBUT of non-tolerant lens wearers was also reduced (average of seven seconds) compared to tolerant lens wearers (p < 0.002). Tolerant lens wearers had a longer more stable tear film with an average TBUT of 20 seconds and this correlated with a fast tear flow rate (p < 0.04). Protein gel electrophoresis showed that some subjects who were non-tolerant to lens wear had variations in their tear protein profiles compared to tolerant subjects. Conclusion : These preliminary results demonstrate that clinical and biochemical tear profiles can be used to differentiate subjects with good lens wear tolerance from those who may be non-tolerant to lens wear.     

Role of tear fluid in the growth of Gram-negative bacteria on contact lenses

Incidents of CLARE (contact lens induced acute red eye) are associated with high numbers of Gram-negative bacteria on the lens surface. This study found that most strains of bacteria implicated in CLARE adhere poorly to the lens surface regardless of whether the lens surface was clean or had been worn in the eye. The high numbers of bacteria on the lens surface result from bacterial growth on the lens surface after adhesion has occurred. Using an artificial tear formulation and real tears, this study demonstrated that the tear fluid provides the necessary nutrients required for bacterial growth.     

术前配戴角膜接触镜对准分子激光原位角膜磨镶术术后泪膜功能的影响

目的了解术前配戴角膜接触镜对准分子激光原位角膜磨镶术（Laser in situ keratomileusis，LASIK）术后泪膜功能的影响。方法对120例（240眼）近视患者行双眼LASIK手术，将研究对象分为对照组（LASIK术前从未配戴角膜接触镜者）和配镜组（LASIK术前连续配戴角膜接触镜时间〉2年者），各60例（120眼），采用双盲法对照研究。观察LASIK前后Schirmer I试验（Schirmer I test，Sit）和泪膜破裂时间（Break-up time，BUT），比较两组间差异是否有统计学意义。结果Sit测量结果：术前、术后第1周、第1个月、第3个月，对照组分别为（18．13±7．48）mm，（14．20±7．81）mm，（16．76±7．38）mm，（17．24±8．06）mm；目6镜组分别为（14．77±8．49）mm，（9．88＋7．50）mm，（13．09±8．23）mm，（13．90±7．87）mm。两组在各时间点比较差异均有显著性（P〈0．05）。BUT测量结果：术前、术后第1周、第1个月、第3个月，对照组分别为（13.21±7．20）S，（7．14±3．97）S，（9．86±3．97）S，（12.31±5．83）S；配镜组分别为（8．98±4．36）S，（4．68±2．85）S，（6．37±3．03）S，（8．19±3．61）S。两组在各时间点比较差异均有显著性（P〈0．05）。结论术前配戴角膜接触镜会影响LASIK术后泪膜功能的恢复，LASIK手术后更应注意补充人工泪液。     

软性角膜接触镜与透气性硬性角膜接触镜对像差的影响

目的 分析配戴软性角膜接触镜、透气性硬性角膜接触镜（rigid gas-permeable contact lens,RGP）患者波前像差及角膜地形图在配戴前后的变化,探讨角膜接触镜对人眼屈光系统成像质量的影响.设计前瞻性随机对照临床研究.研究对象近视眼患者41例（80眼）.方法 软镜组20例（40眼）配戴软性角膜接触镜,RGP组21例（40眼）配戴RGP镜片,患者治疗前后作角膜地形图及波前像差检查,随访观察12个月.主要指标观察配戴接触镜治疗前后角膜地形图及波前像差的变化.结果 软镜组患者治疗后角膜表面规则指数（surface regularityindex,SRI）及角膜表面非对称指数（surface asymne-tryindex,SAI）有所增加,而RGP组SRI及SAI轻度下降;戴镜条件下,两组的整体波前像差（软镜组：0.58;RGP组：0.91）均低于治疗前裸眼的整体波前像差（软镜组：0.71;RGP组：1.21）;配戴后裸眼条件下,RGP组整体像差低于治疗前,且以低阶像差下降为主,而软镜组整体像差高于治疗前,各阶像差呈均匀上升趋势.结论 良好配适状态下的角膜接触镜均可使像差减小,使患者获得优质的光学矫正.     

Tear film dynamics of a new soft contact lens

Purpose

To present the objective metrics from a study that evaluated the clinical performance of a senofilcon A contact lens, both with and without a new manufacturing technique.

Methods

This was a single-site, five-visit, controlled, randomised, subject-masked, 2 × 2 crossover study (May–August 2021) with a 2-week lens dispensing period (bilateral wear) and weekly follow-up visits. Healthy adult (18–39 years), habitual spherical silicone hydrogel contact lens wearers were included. The High-definition (HD) Analyzer™ was used to objectively measure the lens-on-eye optical system resulting from the study lenses at 1-week follow-up. Measurements assessed were vision break-up time (VBUT), modulation transfer function (MTF) cutoff, Strehl ratio (SR), potential visual acuity (PVA) for 100% contrast and objective scatter index (OSI).

Results

Of the 50 enrolled participants, 47 (94.0%) were randomly assigned to one of the two possible lens wear sequences (test/control or control/test) and dispensed at least one study lens. The estimated odds ratio of VBUT > 10 s was 1.582 (95% confidence interval [CI]: 1.009 to 2.482) in test versus control lens. The least squares mean difference estimates of MTF cutoff, SR and PVA for 100% contrast between test versus control lens were 2.243 (95% CI: 0.012 to 4.475), 0.011 (95% CI: −0.002 to 0.023) and 0.073 (95% CI: −0.001 to 0.147), respectively. The estimated ratio of median OSI between test versus control lens was 0.887 (95% CI: 0.727 to 1.081). The test lens demonstrated superiority over the control lens with respect to VBUT and MTF cutoff. No serious adverse events were reported; eight adverse events (three ocular, five non-ocular) were indicated by six participants during the study.

Conclusion

The test lens demonstrated an increased probability of having a longer VBUT (>10 s). Future studies may be designed to assess the efficacy and long-term use of the test lens in a larger population.     

光学治疗区偏心与角膜塑形镜配戴后泪膜功能及角膜形态的相关性分析

目的：探讨光学治疗区偏心与角膜塑形镜配戴后泪膜功能及角膜形态的相关性。

方法：选取于本院配戴角膜塑形镜的80例80眼青少年近视患者为研究对象。于戴镜前后不同时间点分别对患者的光学治疗区偏心距离、泪膜功能及角膜形态指标进行检测。根据中位偏心距离,将患者分为低度偏心组和高度偏心组,比较两组患者戴镜前后不同时间点泪膜功能及角膜形态指标的差异。采用Pearson相关法分析戴镜后12mo时总偏心距离与泪膜功能及角膜形态指标的相关性。

结果：与戴镜前相比,两组患者戴镜后1wk,3、6、12mo的角膜表面非对称性指数、角膜表面规则性指数均明显升高,差异均有统计学意义(P<0.05),且高度偏心组患者较低度偏心组患者升高更为显著,差异均有统计学意义(P<0.05); 泪膜破裂时间、角膜曲率、基础泪液分泌量、中央角膜厚度均明显降低,差异均有统计学意义(P<0.05),且高度偏心组患者较低度偏心组患者在泪膜破裂时间、基础泪液分泌量方面降低更为显著,差异均有统计学意义(P<0.05),但角膜曲率、中央角膜厚度下降程度则较低(P<0.05); 角膜内皮细胞密度在戴镜后1wk和3mo无明显差异(P>0.05),在戴镜后6、12mo差异有统计学意义(P<0.05)。在戴镜后12mo,总偏心距离与角膜表面非对称性指数、角膜表面规则性指数均呈正相关(r=0.869、0.815,均P<0.05),与泪膜破裂时间、角膜曲率、基础泪液分泌量、中央角膜厚度均呈负相关(r=-0.865、-0.745、-0.912、-0.713,均P<0.05),与角膜内皮细胞密度未见明显相关性(r=0.185,P=0.199)。

结论：光学治疗区偏心发生在戴镜起始阶段,且总偏心距离与角膜塑形镜配戴后泪膜功能及角膜形态的改变具有明显相关性。     

Surface hydration of hydrogel contact lenses

A hand refractometer was used to measure the surface hydration of soft contact lenses of three different water contents, in a randomized, double masked study conducted on nine subjects. No statistically significant difference was found after 30 minutes of lens wear between the hydration levels at the front and back surfaces of Permathin (42.5 % nominal water content) and Snoflex 50 (50% nominal water content) hydrogel lenses; however, there was a significant difference for Gelfiex 60 (60% nominal water content) lenses, the back surface being more hydrated than the front surface. These findings suggest that there may be a water gradient between the front and back surfaces of higher water content hydrogel lenses during wear. Whilst the magnitude of the difference between surface hydration levels is small and of little consequence in the routine clinical measurement of water content using a hand refractometer, this phenomenon could be of aetiological significance with respect to the occurrence of multiple corneal erosions observed in patients wearing very thin, high water content lenses.