Non‐invasive tear break‐up time in normal Malays

Background : Tear stability in normal Malays with consideration of gender and age has not been reported. In this study, we measured tear stability in normal Malays using the non‐invasive tear break‐up time (NIBUT). Methods : Forty‐eight Malay subjects aged seven to 60 years were recruited from among the staff, their children and students of the faculty. NIBUT was measured by noting the time taken for distortions to appear in a reflected image of a grid pattern formed on the corneal surface. Results : The mean NIBUT of the sample was 15.8 ± 9.4 (SD) seconds. The median was 14.6 seconds with range of 4.2 seconds to 48.6 seconds. The majority (73 per cent) of subjects had NIBUT values between six and 20 seconds. There was no significant difference in NIBUT values between males and females but there was a decrease of NIBUT with age. Conclusion : The NIBUT values found in this study are comparable to those reported for Asian populations but much less than those of Western populations. Our findings point to the need for local clinical studies in contact lens and contact lens‐related research as tear physiology of the local population may not be the same as in Western populations.     

Variability of the Schirmer tear test values in a normal Arab population

Background: As in many parts of the world, the Schirmer tear test is the main test used by optometrists in Saudi Arabia for assessing adequacy of tear production. Variability of the test has been reported in different ethnic groups but not in Arabs. This paper looks at the mean and repeatability of the values obtained by the Schirmer test in a normal Arab population Method: The test was performed on the right eyes of 23 young adult Saudi male subjects at five visits over two weeks. Result: Results showed that for each subject the test values were not repeatable, varying widely over the period of evaluation. The mean value was estimated at 10.6 mm and the 95 per cent confidence limits were 7.9 and 13.3 mm. It was also established that the greater the amount of tears, the greater the variability. Conclusion: This study supports the claim that the Schirmer test is not repeatable and hence is unreliable. Therefore, caution should be exercised in employing it for clinical diagnosis. (Clin Exp Optom 1995; 78: 5: 190–193)     

Keratograph眼表综合分析仪与传统方法对泪膜功能评价的一致性分析

目的：探讨一种最新的眼表综合分析仪Keratograph对于泪膜稳定性评估的重复性和准确性,将其测量值与传统的检查方法进行比较。

方法：采用Keratograph测量包括首次泪膜破裂时间(the first tear film break-up time, BUT-f)和平均泪膜破裂时间(the average tear film break-up time, BUT-ave)在内的非侵入式泪膜破裂时间(noninvasive tear film break-up time, NI_BUT)结果。测量结果的重复性使用变异系数(coefficient of variation,CV)和组内相关系数(intraclass correlation coefficient,ICC)进行评价, NI-BUT与传统的荧光素泪膜破裂时间(fluorescein tear film break-up time, FBUT)的比较采用Wilcoxon符号秩和检验,确定NI-BUT与FBUT,Schirmer Ⅰ试验结果的相关关系,采用Bland-Altman分析进行一致性评价。

结果：本研究纳入了48个受检者(48眼),平均年龄38.7±15.2岁。BUT-f的CV和ICC分别为12.6%和0.95,BUT-ave的为9.8%和0.96。BUT-f值低于FBUT值,差异有统计学意义(6.16±2.46s vs 7.46±1.92s, P < 0.01)。NI-BUT与FBUT,Schirmer Ⅰ试验结果之间存在显著的正相关关系(P<0.01)。BUT-f与FBUT的95%一致性界限(limits of agreement, LoA)范围为4.46s,BUT-ave与FBUT的LoA范围为3.64s。

结论：Keratograph能够提供具有较好重复性和可靠性的NI-BUT数据,在干眼诊治和角膜屈光性手术等领域有很好的应用前景。     

The effect of vertical gaze position on ocular tear film stability

Background: An enlarged exposed ocular surface area is known to degrade tear film stability. Little is known of how tear film stability alters with vertical gaze and the change of palpebral fissure height Methods: Tear film break‐up time (TBUT; fluorescent dye) and palpebral fissure height were measured in three vertical gaze positions (primary position and 20 degrees up and 20 degrees down) on 23 healthy volunteers. The effect of gaze direction on TBUT was analysed by ANOVA. Results: Gaze had a significant influence on tear film stability [F(2,44) = 27.6, p < 0.001]. In up‐gaze with an enlarged palpebral fissure height (11.1 ± 1.4 mm), TBUT was degraded (17.3 ± 12.7 seconds). In down‐gaze and decreased palpebral fissure height (6.7 ± 1.2 mm) TBUT was extended (43.5 ± 35.4 seconds). Conclusion: Ocular tear film stability alters with vertical gaze. Our hypothesis is that the change of the palpebral fissure height and the exposed ocular surface area alters the thickness of the lipid layer and with it tear film evaporation.     

翼状胬肉切除联合角膜缘干细胞移植术前术后的泪膜变化

目的：探讨翼状胬肉切除联合角膜缘干细胞移植手术前、术后泪膜功能的变化。方法：对24例24眼翼状胬肉患者行逆向胬肉切除联合自体角膜缘干细胞移植术,分别于术前1d;术后1,2mo行Schirmer试验和泪膜破裂时间（BUT）检查,比较各时间点上泪膜的稳定性。结果：患者24例术前1d;术后1,2mo SchirmerⅠ试验分别为15.5±7.81,15.76±7.39,16.00±8.05mm,BUT分别为8.15±3.611,10.05±3.03,10.50±4.26s,术前术后BUT差异具有统计学意义（P〈0.05）,Schirmer试验术后与术前比较无明显变化（P〉0.05）。结论：翼状胬肉切除联合角膜缘干细胞移植可以恢复眼表的形态及泪膜功能的稳定性。     

准分子激光角膜原位磨镶术后泪膜变化及与角膜知觉关系的研究

目的 :探讨准分子激光角膜原位磨镶术 (laserinsitukeratomileusis ,LASIK )后泪液 ,泪膜变化及其与角膜知觉的关系 ,研究LASIK术后发生眼干现象的原因。方法 :对 5 0名近视眼患者实施双眼LASIK手术 ,分别测定其术前 ,术后一周 ,二周和四周的泪液分泌值 ,泪膜稳定性和角膜知觉值 ,其中泪液分泌值用Schirmerl实验测定 ,泪膜稳定性是通过用英国产KEELER泪膜镜测定非侵入性泪膜破裂时间(NIBUT)来评价 ,角膜知觉用美国产CochetBonnet角膜知觉计来测定。结果 :1 NIBUT值 (单位 :秒 ) :术前为 2 6 2 0± 15 12 ,术后一周为 18 5 6± 15 2 4,术后二周为 18 90± 11 64 ,术后四周为2 4 10± 14 2 4,术后各组分别与术前的NIBUT值进行配对t检验 ,差异均有显著性意义 (P <0 0 5 )。 2 角膜知觉 (单位 :mm) :术前为 5 5 60± 8 18,术后一周为 2 4 78± 19 82 ,术后二周为 3 4 0 2± 19 2 8,术后四周为 5 3 3 0± 10 3 8,术后各组分别与术前的角膜知觉值进行配对t检验 ,术后一周、二周组与术前的差异均有显著性意义 (P <0 0 5 ) ,术后四周与术前的差异无显著性意义 (P >0 0 5 )。 3 Schirmerl值 (单位 :mm ) :术前为 2 0 92± 10 80 ,术后一周为 17 83± 10 64 ,术后二周为 2 0 0 6±11 42 ,术后四周     

The acute effects of sildenafil on tear functions

The acute effects of 50 mg of sildenafil on tear functions were evaluated in 12 impotent patients. Mean tear breakup time, cotton thread, and Schirmer I tests were 19.42±6.45 s, 13.92±6.63 mm, and 16.58±12.19 mm, respectively before sildenafil and 20.33±10.40 s, 10.92±6.14 mm, and 18.08±12.36 mm, respectively, 1 hour after sildenafil. The results suggest that sildenafil does not adversely affect tear functions. The authors have stated that they do not have a significant financial interest or other relationship with any product manufacturer or provider of services discussed in this article. The authors also do not discuss the use of off-label products, which includes unlabeled, unapproved, or investigative products or devices.     

The influence of religious fasting on basal tear secretion and tear break-up time

Muslims abstain from food and drink from dawn to sunset during the holy month of Ramadan. An extended strict fasting may influence tear secretion and quality. We investigated changes in basal tear secretion (BTS) and tear break-up time (BUT) at the beginning and at the end of fasting on 32 healthy male patients with a mean age of 22.3 ± 2.9 years. Body weight and urine specific gravity were also determined to assess the extent of dehydration due to fasting. Each case lost 0.1–1.25 kg of body weight while urine specific gravity changes were statistically insignificant. Mean BTS amount was 19.9 ± 10.9 mm at the initial examination and 19.7 ± 11.5 mm at the end of fasting (p=0.9). BUT values were 20.1 ± 9.3 sec at the beginning of fasting and 23.5 ± 14.9 sec at the end of fasting (p=0.19). We found that religious fasting in the winter season does not seem to affect BTS and BUT values in healthy individuals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Association between tear film break up time and blink interval in visual display terminal users

AIM: To investigate the association between tear film break up time (TBUT) and blinking interval in visual display terminal (VDT) users. METHODS: Nine hundred and thirty VDT users underwent dry eye testing, and functional visual acuity (FVA) test. The blinking interval during FVA was compared with TBUT. Subjects with longer blinking interval than TBUT were considered as unstable tear film. Logistic regression analysis revealed the risk factors for unstable tear group. RESULTS: Among 930 workers, 858 subjects (92.3%) participated in this study. Almost 80% of the subjects were categorized into the unstable tear group. Unstable tear group has significantly lower Schirmer values and TBUT (17.5±11.6 vs 21.1±11.5 mm, 3.7±2.6 vs 5.7±2.7s, both P<0.001). There were no significant differences in epithelial staining or severity of symptoms. Logistic regression showed that over 40y was a risk for being unstable tear group [odds ratio (OR)=1.53; 95% confidence interval (CI)=1.06-2.20]. Contact lens use was protective factor for being in the unstable tear group (OR=0.37; 95%CI= 0.26-0.53). CONCLUSION: Subjects with shorter TBUT than blinking interval are prevalent among VDT users. Subjects over the age of 40 shows an increased risk for unstable tear film.     

The relation between tear film tests in patients with dry eye disease

PURPOSE: The purpose of this report was to investigate the relation between dry eye diagnostic tests. METHODS: Dry eye patients were enrolled to complete a clinical examination, including the following dry eye tests: a meibomian gland evaluation, tear meniscus height, fluorescein tear breakup time, fluorescein staining of the cornea, the Schirmer 1 test, the phenol red thread test, and rose bengal staining of the conjunctiva. Statistical analyses, including correlation coefficients, the Wilcoxon sign rank test, chi-square test, and logistic regression were used to address the relation between these clinical tests of dry eye. RESULTS: There was a strong relation between the Schirmer test and fluorescein staining in all four statistical analyses. Similarly, there was also a strong relation between the phenol red thread test and both fluorescein and rose bengal staining. Finally, the results of the Schirmer test were associated with the tear breakup time test in three of four analyses. CONCLUSIONS: The results indicate that tests of aqueous deficiency (volume or production) are associated with ocular surface desiccation. This important relation should be recognized when choosing dry eye tests as outcomes in clinical trials and epidemiological studies.     

Relationship between goblet cell density and tear function tests

AIM: The objective of this study was to find a relationship between goblet cell density (GCD) and other diagnostic tests of dry eye in a group of normal healthy Chinese subjects. The capability of using GCD as a tear function test was assessed. METHOD: A total of 42 optometry students with no contact lens wear history were recruited. Subjects were required to fill in a dry eye questionnaire. The non-invasive tear break-up time (NITBUT) of each subject was measured, followed by phenol red thread test (PRTT) and tear break-up time (TBUT) tests. Conjunctival epithelial cells from the inferior nasal bulbar conjunctiva were harvested by the impression cytology technique. The specimens collected were labelled and stained with PAS (Periodic Acid Schiff)-haematoxylin. The goblet cells and the conjunctival epithelial cells were counted under a light microscope of 100x magnification. Spearman's rho (rho) correlation test was used to analyse the relationship between GCD and the other tear function tests. RESULTS: With a probability level of 0.0051 (corrected for a cumulative familywise error rate of p = 0.05), GCD was found to have no correlation with NITBUT (rho = -0.193, p = 0.222), McMonnies Dry Eye Scores (MCDES) (rho = -0.052, p = 0.742), PRTT (rho = - 0.188, p = 0.234) and TBUT (rho = 0.246, p = 0.117). CONCLUSION: There was no correlation between GCD and MCDES, NITBUT, PRTT and TBUT. The GCD alone is not a useful diagnostic test for tear film instability in normal eyes although it is a good indicator in the diagnosis of ocular surface diseases.     

干眼患者基于泪膜动态变化的图像特征分析

目的:探讨干眼患者角膜荧光素染色后泪膜破裂动态变化和泪膜脂质层动态变化的图像特征及其对干眼的诊断价值。方法:前瞻性研究。选取我院2019-09/2020-12收治的干眼患者66例132眼,根据荧光素染色后泪膜破裂形态的不同分为片状破裂组(17例28眼)、类圆形破裂组(20例27眼)、线状破裂组(25例28眼)、点状破裂组(21例24眼)和不规则破裂组(20例25眼),比较各组患者泪膜破裂动态变化图像特征、泪膜脂质层动态变化图像特征及泪膜首次破裂时间(NIBUTf)、泪膜平均破裂时间(NIBUTav)、泪河高度(TMH)、角膜荧光素染色(FL)评分的差异。结果:各组患者NIBUTf有差异(P<0.001),除点状破裂组和不规则破裂组间无差异(7.56±1.54s vs 8.02±1.86s,P=0.881),其余各组两两比较均有差异(P<0.05)。各组间NIBUTav有差异(P<0.001),除点状破裂组和不规则破裂组间无差异(9.54±2.12s vs 9.73±1.94s,P=0.997),其余各组两两比较均有差异(P<0.05)。各组间TMH比较有差异(P...     

单侧翼状胬肉患者50例泪液功能的改变(英文)

目的:检测泪液功能试验(SchirmerⅠtest,SⅠt)及泪膜破裂时间(tear filmbreak-up time,TBUT)在翼状胬肉患者中的改变。方法:筛选50例患者(100眼,50例翼状胬肉眼),行SⅠt及TBUT试验。结果:SⅠt试验在翼状胬肉眼的平均值为19.6±11.6 (1 ～40) mm,对照眼为17.2±10.6(1 ～35)mm,翼状胬肉眼中20例(40%)SⅠt试验结果异常,对照眼为21例(42%),其差异无统计学意义(P=075)。两组间差异无统计学意义(t=1.453,P=0.15)。TBUT在翼状胬肉眼及对照眼中分别为7.4±5.1 ( 2 ～20)s, 13.4±6.1 (2 ～25)s,两组间的差异有显著统计学意义(t=8.029,P<0.01)。翼状胬肉眼中TBUT异常的为39眼(78%),对照眼中为16眼(32%);差异有显著统计学意义(P<0.01)。结论:与对照眼相比较,SⅠt试验在翼状胬肉眼中差异无统计学意义,TBUT在翼状胬肉眼中有所下降。     

The repeatability of clinical measurements of dry eye

PURPOSE: The repeatability of individual dry eye diagnostic tests has been reported in the literature on normal samples of patients and to a lesser degree in dry eye patients. In this study, the repeatability of a battery of clinical diagnostic tests for dry eye was assessed on mild to moderate dry eye patients. METHODS: A dry eye examination was performed on 75 patients on two occasions by a single examiner. The battery of dry eye tests included symptom assessment, contact lens and medical history, slit-lamp biomicroscopic evaluation of the eyelids, evaluation of Meibomian glands, assessment of tear film quality, tear meniscus height, assessment of blink quality, fluorescein tear breakup time (TBUT), fluorescein and rose bengal staining of the cornea and conjunctiva, phenol red thread test, and Schirmer test. RESULTS: The repeatability of subjective report of dryness (kappaW = 0.62) and grittiness (kappaW = 0.73) was moderate to high. In contrast, the repeatability of Meibomian gland disease classification (kappaW = 0.20), presence or absence of inferior corneal fluorescein staining (kappa = 0.25), and inferior conjunctival rose bengal staining (kappa = 0.21) was poor. When a summed staining score of corneal and conjunctival regions was evaluated, weighted kappa reliability was fair. The repeatability of tear breakup time was substantial [95% limits of agreement -5.71 to 5.83 seconds; intraclass coefficient coefficient (ICC) 0.65], and improved when the two timed readings were averaged. Repeatability of the Schirmer test is more variable as wetting scores increase. When the average Schirmer scores 相似文献   

Tear Film and Ocular Surface Evaluation in Gestational Diabetes Mellitus

Background: Dry eye syndrome is one of the complaints of diabetic patients. The aim of the present study was to evaluate the tear functions in pregnant women with gestational diabetes mellitus (GDM) using tests: Schirmer, tear break-up time (TBUT), and tear film osmolarity (TFO) tests and the Ocular Surface Disease Index score (OSDI). Methods: Pregnant women with GDM (Group 1, n=46) and healthy pregnant women (Group 2, n=36) were enrolled. Initially, all participants were asked to answer the OSDI and then they underwent a detailed ophthalmic examination including Schirmer, TBUT, and TFO tests. The individuals with ocular or systemic disorders that might affect the tear function tests and who were using topical medications were excluded. Results: The results of Schirmer, TBUT, TFO tests and OSDI scores were 11.20±4.93 mm, 5.59±2.16 sec, 309.65±14.80 mOsm/L, and 9.59 ± 9.69 in Group 1, respectively, and 12.33±5.33 mm, 5.67±2.68 sec, 308.36±16.00 mOsm/L, and 10.62±8.66 in Group 2, respectively. There was no significant difference in any of the tear function tests and OSDI scores between the study groups (p>0.05). Conclusion: GDM seems to have no negative effects on tear function tests. This may be due to a lack of duration of hyperglycemia long enough to affect the tear function tests of pregnant women.     

超声乳化白内障吸除术后泪膜和泪液分泌变化的Meta分析

目的:探讨超声乳化白内障吸除术对泪膜及泪液分泌变化的影响。方法:检索PubMed,Web of knowledge、中华期刊网和中国生物医学文献数据库,辅以Google网络检索和手工检索,筛选得到6篇2000-01/2009-08发表的关于超声乳化白内障吸除术对泪膜和泪液分泌变化影响的研究,以手术前与术后3mo泪膜破裂时间(break-up time,BUT)和基础泪液分泌试验(SchirmerⅠtest,SⅠt)均数差值(relativedifference,RD)为效应指标,应用随机效应模型对入选文献的数据资料进行Meta分析。结果:术后3mo时BUT仍低于手术前水平,差异有统计学意义[RD的加权平均估计值为1.34,95%可信区间为(0.40,2.30),P=0.01]。术后3mo时SⅠt值略低于手术前水平,但差异无统计学意义[RD的加权平均估计值为0.80,95%可信区间为(-0.14,1.75),P=0.10]。结论:术后3mo时,超声乳化白内障吸除术后泪膜稳定性仍降低,但基础泪液分泌量已基本恢复至术前水平。     

Thinning rate of the precorneal and prelens tear films

PURPOSE: To apply interferometry as an in vivo measure of tear film thinning between blinks. METHODS: Wavelength-dependent interference was used to measure the tear film thinning rates in 20 normal contact lens wearers, and spectra were captured at a rate of 4.5 per second for 20 seconds. Four recordings of precorneal tear film (PCTF) thinning were made, followed by 1 hour of hydrogel lens wear and then four recordings of prelens tear film (PLTF) thinning. Subjects were asked to blink 1 second after the beginning of the recording and then hold their eyes open for an additional 19 seconds, followed by 2 minutes of rest between recordings. RESULTS: The average thinning rate of the PLTF was greater than that of the PCTF and average initial tear film thickness of the PLTF was less than that of the PCTF. For both these reasons, the "tear thinning time" (time to reach 0 thickness) was typically shorter for the PLTF than for the PCTF. Histograms of PCTF and PLTF thinning rates showed a narrow peak corresponding to slow thinning of approximately 1 microm/min, but also many examples of rapid thinning of approximately 10 microm/min, with greater variability. Both the initial thickness and thinning rate of the PLTF correlated with corresponding values for the PCTF, although many more rapidly changing values were associated with the PLTF. Plots of rapid thinning of PCTF and PLTF were both linear and were not accompanied by any significant increase in thickness of corneal epithelium or contact lens, respectively. CONCLUSIONS: Tear film thinning can be analyzed in terms of flow in three spatial directions: (1) outward (evaporation), (2) inward (into the epithelium or contact lens), and (3) parallel to the tear film surface. The results indicate that the second mechanism may be unimportant. Studies have shown a range of tear film evaporation rates from 0.24 to 1.45 microm/min, whereas, when the lipid layer is washed away from the tear film, the thinning rate, due to evaporation, would be approximately 7 microm/min. Thus, slow thinning rates may be due to tear film evaporation, whereas rapid rates (which are often greater than 7 microm/min) presumably include other mechanisms such as dewetting, Marangoni flow (i.e., surface tension gradients), and pressure-gradient flow.     

翼状胬肉切除联合带蒂结膜瓣移植术对泪液功能的影响

目的:评价翼状胬肉切除联合带蒂结膜瓣移植术对翼状胬肉患者泪液功能的影响情况。 方法:对入选的翼状胬肉患者行胬肉切除联合带蒂结膜瓣移植手术,在术前1d;术后3,7d;术后1mo做泪膜破裂时间(BUT) 、泪液分泌(Schirmer Ⅰ)试验和泪液羊齿状试验(TFT),在术前1d和术后1mo做结膜印迹细胞学检查, 以评价患者术前、术后的泪液功能。 结果:共纳入87例87眼患者,其中男45例, 女42例。年龄45～81（ 平均64.1±8.8）岁。术后1mo BUT较术前1d延长,分别为11.47±3.23s和9.43±3.25s (P<0.05);术前羊齿状试验结果正常(Ⅰ级和Ⅱ级)的患者占22%,术后1mo正常的患者增加至90%,术后1mo TFT较术前明显改善(P<0.05);术后杯状细胞密度要高于术前结膜杯状细胞密度,分别为39.73±18.46个/10个高倍镜和48.85±18.80/10个高倍镜 (P<0.05)。泪液分泌Ⅰ试验结果显示术后早期分泌较术前增多(P<0.05),但术前、术后晚期差异无显著意义(P>0.05) 。 结论:胬肉切除联合带蒂结膜瓣移植术手术前后的泪液功能明显有改变, 手术可使患者的泪液功能得到一定的恢复。     

Temporal changes in the tear menisci following a blink

This study investigated tear meniscus formation after a blink. Multiple images of the inferior and superior menisci, viewed en-face, were sequentially captured using a video-slitlamp that permitted the measurement of tear meniscus height (TMH). In a similar manner, tangentially viewed images were obtained of the inferior meniscus so changes in cross-sectional radius of curvature (TMR) with time could be determined. Additionally, the relationship between inferior TMH and tear volume was quantified by the successive instillation of small aliquots of fluid. In this latter experiment the inflow and outflow of tears were controlled by anaesthetizing the ocular surface and inner nose, and use of punctal plugs. The TMH of both menisci rose after a blink (p<0.01) by a similar amount (p=0.59). This suggests that capillarity is dominant over gravity in tear drainage, however, it may simply reflect that these influences are small compared to the large flow resistances that occur in thin films, hydraulic connectivity between the two menisci, or differences in their anterior-posterior width leading to unequal volume-height relationships. TMR increased with time after a blink (p<0.0001); immediately on eye opening the curvature of the inferior meniscus was approximately circular but this soon became eccentric, with the radius of its upper half exceeding that of its lower half. The growth rate of the two menisci slowed with time and this, based on theoretical considerations, is predicted to have occurred primarily because localized thinning of the tear film adjacent to the menisci markedly raised flow resistance. Inferior TMH increased linearly with the cumulative volume of instilled fluid (r2=0.98), supporting its use in the diagnosis and classification of tear anomalies, although the gradient of this relationship varied between subjects.