睑缘炎、睑板腺功能障碍与干眼症

睑板腺通过分泌睑脂组成泪膜脂质层 ,防止泪液过度蒸发 ,促进泪膜稳定性。睑缘炎和睑板腺功能障碍破坏正常的睑脂分泌 ,使泪液蒸发过强 ,是蒸发过强型干眼症的最常见原因。目前对睑板腺和泪膜脂质层功能评价的认识尚不足。本文就睑缘和睑板腺的功能特点和临床评价、睑缘炎和睑板腺功能障碍与干眼症的关系以及治疗进展进行综述     

睑缘炎、睑板腺功能障碍与干眼症

睑板腺通过分泌睑脂组成泪膜脂质层，防止泪液过度蒸发，促进泪膜稳定性。睑缘炎和睑板腺功能障碍破坏正常的睑脂分泌，使泪液蒸发过强，是蒸发过强型干眼症的最常见原因。目前对睑板腺和泪膜脂质层功能评价的认识尚不足。本就睑缘和睑板腺的功能特点和临床评价、睑缘炎和睑4板腺功能障碍与干眼症的关系以及治疗进展进行综述。     

睑缘炎所致泪膜损害23例

目的探讨睑缘炎对泪膜的损害作用。方法对23例严重睑缘炎患者进行详细裂隙灯检查、泪膜破裂时间、泪液分泌试验测定及角膜上皮荧光素染色。观察经药物治疗后上述各项的改变。结果23例患者睑缘充血、不规则,睫毛根部及睑板腺开口处黄色分泌物及痂皮附着,泪膜破裂时间缩短,角膜弥漫着色,泪液分泌试验在正常范围。结论睑缘炎引起脂质分泌减少及成分异常,破坏泪膜稳定性,导致蒸发过强型干眼。     

睑板腺功能障碍研究进展

睑板腺功能障碍(meibomian gland dysfunction,MGD)以睑板腺终末导管阻塞和睑板腺分泌物的质量或数量改变为特征.睑板腺分泌的脂质成分发生相应改变,造成泪膜的稳定性下降和泪液蒸发量增加,从而导致干眼发生.目前MGD的发病原因尚不明确,临床上采取的治疗往往是对症治疗.本文主要对MGD的泪膜脂质变化及其国内外诊治进展进行总结.     

干眼症患者睑板腺形态分析

干眼是眼科高发疾病,国内流行病学调查显示其发病率为30．05％［1］、24．8％［2］和23．6％［3］。目前干眼症分为泪液分泌不足和蒸发过强两类,睑板腺功能障碍被认为是蒸发过强型干眼症的主要病因之一［4］。传统干眼症检查手段主要为泪液分泌试验和泪膜破裂时间检查,随着检查设备的发展,近年来对睑板腺形态观察逐步应用到临床。美国和日本的学者研究报道,正常人群中睑板腺异常占20％～55％［5］,在干眼症患者中睑板腺异常比例高达65％［6］。本研究通过非接触红外线睑板腺照相对干眼症患者的睑板腺形态进行客观检查,分析睑板腺异常在不同程度干眼症患者中所占比例,以期为探讨干眼症的病因及治疗提供临床依据。     

睑脂成分改变对泪膜表面张力的影响

泪膜表面张力是泪膜一个重要的物理性能,它能让泪液均匀地涂布于眼球表面并形成一个稳定的膜性结构.泪膜脂质层主要由睑板腺分泌的脂质构成,睑脂中具有表面活性的脂质成分如磷脂质、游离脂肪酸、o-酰基-ω-羟基脂肪酸等,可在泪膜的非极性脂质层与极性水液层之间形成稳定单分子膜层的两性界面,表面活性分子的性质和活性是维持界面张力的关键因素,降低泪膜表面张力而增加泪膜稳定性,从而延长泪膜破裂时间.     

提高对睑板腺功能障碍的认识 重视睑板腺功能障碍相关性干眼的药物治疗

睑板腺功能障碍（MGD）是临床常见的眼表疾病,以睑板腺终末导管的阻塞和／或睑板腺分泌物质或量的改变为特征,导致脂质向泪膜的排出减少,引起泪液蒸发过强。睑缘和睑板腺的炎症是引起睑板腺阻塞,进而导致MGD的直接原因,可引起眼表功能的异常。MGD的诊断主要依靠临床症状与体征,其症状与干眼的症状相似,因此无诊断特异性。体征主要包括睑缘形态的变化、睑板腺分泌异常和睑板腺缺失。MGD的治疗方法包括热敷、清洁睑缘、促进睑板腺的分泌、抗菌、抗炎治疗及润滑眼表,中度、重度MGD患者可给予必要的抗炎治疗,常用的抗炎药物有糖皮质激素、非甾体类抗炎药及免疫抑制剂。临床医师在进行眼部疾病的检查时应重视睑板腺的功能状态,尤其在角膜屈光手术及内眼手术前更应重视MGD的筛查,以免术后引起严重的眼表并发症,有效规避医疗风险。     

蒸发过强型干眼的泪膜脂质层成分变化及治疗策略

泪膜包括脂质层和由水及黏蛋白构成的凝胶层,其中脂质层又分为极性和非极性两层。非极性脂质的成分为蜡酯、固醇酯、甘油三酯等,而极性脂质层主要是磷脂类。蒸发过强型干眼患者的泪膜脂质层成分不同于正常者,而泪液脂质层对于稳定泪膜、减少蒸发具有重要意义,因此蒸发过强型干眼治疗的关键在于补充和稳定泪膜脂质,既可以作为单一疗法也可以联合补充泪液的治疗。     

睑板腺功能异常

睑板腺功能异常是一种常见的眼表面疾病,可引起眼红,眼部痒、烧灼感、干燥感、刺激感,视力波动或流泪等眼部不适症状,可导致脂质缺乏性干眼症、睑缘炎、结膜炎、点状角膜炎及其他眼表面疾病.睑板腺开口阻塞是睑板腺功能障碍的最常见原因,阻塞可直接或间接引起睑板腺分泌物数量和质量改变,造成泪膜不稳定,脂质减少也可引起泪液蒸发加快,导致眼表面干燥.     

睑板腺功能障碍临床诊断新进展

睑板腺功能障碍(meibomian gland dysfunction,MGD)是眼科门诊常见的疾病之一,临床上MGD的诊断需根据症状、体征和相应的辅助检查进行综合评估。传统的检查方法如裂隙灯检查、泪膜破裂时间、泪液分泌试验等在MGD的诊断中有着明确的价值,而在2017年我国睑板腺功能障碍诊断与治疗专家共识中,一些新兴的临床检查方法如睑板腺缺失率、泪膜脂质层厚度等也作为MGD的辅助诊断标准。传统的方法和新兴的检测技术结合起来用于MGD的诊断,将会得到更全面、准确的结论。     

局部抗青光眼药物中苯扎氯胺导致干眼症的研究进展

A large part of glaucoma patients who have been treated with topical anti-glaucoma drugs for a period have experienced dry eye of varying degrees. Preservatives in anti-glaucoma drugs, particularly benzalkonium chloride (BAK）, are believed to play a major role in the development of dry eye in patients. Based on existing research, this paper summarizes several main mechanisms of benzalamine causing dry eye. BAK can directly acts on tear film and destroy tear film stability, resulting in tear evaporation increasing and tear film osmolarity elevating. BAK has cytotoxic effects on corneal epithelial cells, conjunctival goblet cells and meibomian gland cells, thus can affect the secretion of mucus and lipid in tear film. BAK can also cause chronic inflammation of the eye surface, leading to discomfort in patients. By exploring the mechanism of BAK causing dry eye, we hope to provide ideas for guiding the use of glaucoma and developing a new antiseptic system for eyedrops.(Int Rev Ophthalmol, 2021, 45：420-425)     

Non-invasive methods of assessing the tear film

The interaction between the tear film and the ocular surface epithelium is crucial for the maintenance of ocular surface health; interference with this relationship may cause dry eye. Several diagnostic techniques have been developed to assess the tear film and diagnose dry eye but many of these tests are invasive and modify the parameter which they are designed to measure. Non-invasive or minimally invasive tests may overcome this problem and provide more reproducible and objective data. One test of this kind is meniscometry, which is particularly useful in assessing tear volume indirectly by measuring tear meniscus radius. The newly developed video-meniscometer, which enables calculation of the meniscus radius digitally, is useful for the diagnosis of tear-deficient dry eye. Video-meniscometry also has other applications, to the study of tear and eye drop turnover, determining the indication for punctal plugs and in demonstrating dysfunction of the tear meniscus. Interferometry of the tear film lipid layer is useful in screening and evaluating dry eye severity and in selecting dry eye candidates for punctal occlusion. It is also useful for analysing tear lipid layer pathophysiology more clearly, especially in combination with meniscometry. Meibometry is a minimally invasive technique to quantify the amount of meibomian lipid on the lid margin. Lipid is blotted onto a plastic tape and the change in optical density is used to calculate lipid uptake. Laser meibometry has increased the scope of this technique for the assessment of meibomian gland dysfunction; also, the delivery of lipids from the lid reservoir to the preocular tear film can be analysed using interferometry and laser meibometry. The present report reviews the application of these techniques to the study of tear film physiology and dry eye.     

Ocular surface changes in moderate-to-severe acne vulgaris

AIM: To investigate ocular surface disorders and tear function changes in patients with acne vulgaris and explore the potential relationship between acne vulgaris and dry eye. METHODS: This cross-sectional study included right eyes of 53 patients with acne vulgaris and 54 healthy controls. The participants completed the Ocular Surface Disease Index (OSDI) questionnaire. The following ocular surface-related parameters were measured: tear meniscus height (TMH), noninvasive tear breakup time (NIBUT), Schirmer I test (SIT), lipid layer thickness (LLT) score of the tear film, meibum score, meibomian gland orifice obstruction score, the ratio of meibomian gland loss, conjunctival hyperemia score, and corneal fluorescein staining (CFS) score. RESULTS: The stability of the tear film decreased in acne vulgaris patients. In the acne group, the TMH and NIBUT were lower, whereas the OSDI, meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss, and conjunctival hyperemia score were higher compared with controls (P<0.05). There were no significant differences in the CFS score, SIT, or LLT score between the groups (P>0.05). In two dry eye groups, the TMH, NIBUT, and LLT score were lower in the acne with dry eye (acne-DE) group, and the meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss and conjunctival hyperemia score in the acne-DE group were higher (P<0.05). There were no significant differences between OSDI, SIT, and CFS score (P>0.05). CONCLUSION: Patients with moderate-to-severe acne vulgaris are more likely to experience dry eye than those without acne vulgaris. Reduced tear film stability and meibomian gland structure dysfunction are more pronounced in patients with moderate-to-severe acne and dry eye.     

Abnormal of tear lipid layer and recent advances in clinical study of dry eye

Dry eye is a common disease in the ophthalmological clinic, which is related to the dysfunction of tear film. The tear film is composed of lipid layer, aqueous layer and mucin layer (or lipid layer, aqueous/mucin layer). The lipid of the outmost layer derived from Meibomian gland and distributed on the tear film after blinking can decrease the evaporation and stabilize the tear film. The thickness, quality, and distribution of lipid layer are impaired in many dry eye patients, hence restoring the physiological function of lipid layer may be crucial for the treatment of this kind of dry eye. The lipid artificial tears manifest great effects on increasing lipid layer thickness, stabilizing tear film, improving Meibomian gland dysfunction, and promoting tear film distribution.     

Trockenes Auge bei Kontaktlinsenträgern

Contact lens-associated dry eye symptoms have mostly been therapeutically addressed using artificial tears containing hyaluronic acid to supplement tear film volume with often unsatisfactory results. However, the main reason for contact lens-associated dry eye is not the lack of tear fluid but the lack of tear film stability due to meibomian gland dysfunction leading to reduction of the lipid film of tears. This is associated with increased evaporation of the aqueous phase of tear fluid and a measurable hyperosmolarity of the residual “denatured” tear film. A subsequent inflammatory reaction of the ocular surface then leads to the vicious circle of dry eye. The aim of this review is to summarize current study results on this topic and to give practical advice on how to address dry eye symptoms in contact lens wearers more accurately. For most contact lens-associated dry eye symptoms a combined therapy with unpreserved artificial tears plus phospholipid-liposome eye spray yields the best results. In cases of additional signs of blepharitis the regular use of phospholipid-liposome solution for lid margin hygiene is beneficial.     

The contribution of meibomian disease to dry eye

The tear film lipid layer is the major barrier to evaporation from the ocular surface. A decrease in its thickness or functional integrity may cause evaporative dry eye (EDE). Obstructive meibomian gland dysfunction (MGD) is the most common cause of EDE and occurs as a primary disorder or secondary to acne rosacea, seborrheic or atopic dermatitis, and with cicatrizing conjunctival disorders, such as trachoma, erythema multiforme, and cicatricial pemphigoid. MGD may be an incidental finding in asymptomatic eyes, or it may be responsible for irritative lid symptoms in the absence of dry eye. MGD-dependent EDE is diagnosed on the basis of a defined degree of MGD in a symptomatic patient showing typical ocular surface damage in the absence of an aqueous tear deficiency. When MGD occurs in a background of aqueous tear deficiency (ATD), then an additional evaporative component may assumed, depending on the extent of meibomian obstruction. However, definitive criteria are not yet established. The clinical severity of dry eye is greatest when ATD and EDE occur together, particularly in Sjogren syndrome. A hypothesis is proposed to explain the steps leading to primary, simple MGD and subsequent EDE.     

Intravitreally injected ranibizumab versus photodynamic therapy for CNV secondary to choroidal osteoma: a 7-year follow-up case report

Meibomian gland, the largest sebaceous gland of the body, is responsible for the biosynthesis of lipid layer of the tear film to prevent excessive evaporation. The loss of normal functions of meibomian gland, known as meibomian gland dysfunction (MGD), is a chronic disease and is the leading cause of dry eye symptoms in the clinics. Studies have found sex hormones, especially androgen, play vital roles in the regulation of the functions of meibomian gland. Recently, androgen has also been preliminarily applied in clinics for the treatment of MGD and showed promising results, especially in people with endogenous androgen deficiency. This review summarized the mechanisms of the function of androgen on meibomian gland based on molecular, animal, and clinical studies, and propose evidence-based views about its potential applications for the treatment of MGD.     

Functional aspects of the tear film lipid layer

The lipid layer is an essential component of the tear film, providing a smooth optical surface for the cornea and retarding evaporation from the eye. The meibomian lipids which compose it are well adapted for this purpose. They form a thin, smooth film whose thickness, and probably composition, influences the rate of evaporation. Their melting range ensures sufficient fluidity for delivery to the tear film from the lid margin reservoirs, while the film itself may exhibit a higher viscosity at the cooler temperature of the ocular surface. The factors governing lipid film formation during the blink are not fully understood, but one view is that the polar lipids, interacting with the aqueous sub-phase of the tear film, spread in advance of the non-polar components, which form the bulk of the film. The meibomian lipids stabilise the tear film by lowering its free energy; they carry water into the film during its formation and interact with lipid-binding proteins in the aqueous phase, such as tear lipocalin. The lipocalins, complexed with other tear components, may also contribute to the high, non-Newtonian viscosity of the tear film and its low surface tension, features which are essential for tear film stability. Formation of the lipid film is a complex process. Lipid is delivered to the tear film in the up-phase of the blink, more from the lower than the upper reservoir. The lipid layer comes to a stop well after completion of the blink and remains relatively immobile until it is compressed in the down-phase of the blink that follows. Then, it either retains its structure in a series of subsequent blinks, or is completely re-constituted after mixing with the reservoir lipids. Delivery of meibomian lipid to the marginal reservoirs is mainly the result of continuous secretion, under neural and hormonal control, supplemented by lid action. The reservoirs provide a hydrophobic barrier to tear overspill and to contamination by skin lipids which might destabilise the tear film. They probably also provide the chief route for meibomian lipid excretion.     

Low-concentration homogenized castor oil eye drops for noninflamed obstructive meibomian gland dysfunction

OBJECTIVE: We developed low-concentration homogenized castor oil eye drops for the treatment of patients with noninflamed obstructive meibomian gland dysfunction (MGD), a major cause of lipid-deficiency dry eye, and assessed the safety, stability, and efficacy of the eye drops. DESIGN: Randomized, double-masked, placebo-controlled crossover clinical trial. PARTICIPANTS: Forty eyes of 20 patients with noninflamed MGD. METHODS: After a preliminary study of eye drops containing castor oil, 2% castor oil and 5% polyoxyethylene castor oil (emulsifier) were mixed to formulate homogenized oil eye drops. The patients were assigned randomly to receive oil eye drops or placebo six times daily for 2 periods of 2 weeks each. MAIN OUTCOME MEASURES: At the end of each treatment period, we assessed symptoms, tear interference grade, tear evaporation, fluorescein and rose bengal scores, tear break-up time (BUT), and meibomian gland orifice obstruction. Safety and stability tests were also performed. RESULTS: Symptom scores, tear interference grade, tear evaporation test results, rose bengal scores, tear BUT, and orifice obstruction scores after the oil eye drop period showed significant improvement compared with the results after the placebo period. No complications attributable to the eye drops were observed. The oil eye drops were stable when stored at 4 degrees C. CONCLUSIONS: The results indicate that castor oil eye drops are effective and safe in the treatment of MGD. The possible mechanisms of this treatment are improvement of tear stability as a result of lipid spreading, ease of meibum expression, prevention of tear evaporation, and the lubricating effect of the oil eye drops.     

地夸磷索钠联合强脉冲光治疗角膜屈光手术后睑板腺功能障碍性干眼

目的:观察地夸磷索钠联合强脉冲光(IPL)对屈光术后睑板腺功能障碍(MGD)性干眼的治疗效果。方法:选取2021-03/12在本院进行激光角膜屈光手术后6mo内确诊的MGD性干眼患者64例128眼。随机分为对照组和试验组,对照组患者33例66眼接受玻璃酸钠联合IPL治疗,试验组患者31例62眼接受地夸磷索钠联合IPL治疗。两组患者每次IPL治疗前均进行眼部症状评分,检查非接触式泪膜破裂时间(NIBUT)、泪河高度、泪膜脂质层分级、睑板腺缺失率及裸眼视力。结果:IPL治疗后,两组患者眼部症状评分、睑板腺缺失率评分均持续降低,NIBUT、泪河高度、泪膜脂质层分级均持续升高,裸眼视力无明显变化,且第3次IPL治疗前试验组患者NIBUT优于对照组(6.24±0.27s vs 5.51±0.24s,P=0.046)。结论:地夸磷索钠和玻璃酸钠联合IPL均对MGD性干眼有较好的治疗效果,但短期内疗效差异不显著。