Assessment of Laser Parameters to Improve Lid Tension-A Proof of Concept towards Lasercanthoplasty.

BACKGROUND: Preliminary clinical work indicates that increasing eyelid tension improves the function of the meibomian glands. The aim of this study was to optimize laser parameters for a minimally invasive laser treatment to increase eyelid tension by coagulation of the lateral tarsal plate and canthus. METHODS: Experiments were performed on a total of 24 porcine lower lids post mortem, with six lids in each group. Three groups were irradiated with an infrared B radiation laser. Laser-induced lower eyelid shortening was measured and the increase in eyelid tension was assessed with a force sensor. A histology was performed to evaluate coagulation size and laser-induced tissue damage. RESULTS: In all three groups, a significant shortening of the eyelids after irradiation was noticed (p < 0.0001). The strongest effect was seen with 1940 nm/1 W/5 s, showing -15.1 ± 3.7% and -2.5 ± 0.6 mm lid shortening. The largest significant increase in eyelid tension was seen after placing the third coagulation. CONCLUSION: Laser coagulation leads to lower eyelid shortening and an increase in lower eyelid tension. The strongest effect with the least tissue damage was shown for laser parameters of 1470 nm/2.5 W/2 s. In vivo studies of this effect have to confirm the efficacy of this concept prior to clinical application.

Lateral Canthal Sling Procedure for Meibomian Gland Dysfunction? Results of a Pilot Study.

Background: Involutional changes of lid structures often induce horizontal lid laxity; this can result in a reduction of Meibomian gland expression, potentially leading to symptoms of dry eye. The aim of this study was to evaluate the effect of tightening the lower eyelid via a lateral canthal sling (LCS) procedure on dry eye parameters.Methods: Patients with Meibomian Gland Dysfunction (MGD), lower lid laxity (positive Snap-back Test and positive Pinch Test) and no previous lid surgery were evaluated before and 3 months after LCS procedure for symptoms by OSDI. The fellow eye without surgery functioned as a control group. MGD parameters included lipid layer thickness (LLT), non-invasive breakup time (NIBUT), tear meniscus height, loss of Meibomian glands, lid margin parallel conjunctival folds (LIPCOFs), Schirmer's test, the number of expressible Meibomian glands as well as quality of Meibum.Results: Fourteen patients (8 men and 6 women; 79.2 ± 4.0 years) were enrolled in this prospective clinical study. After 3 months, the OSDI showed a significant reduction (preop 42.9 ± 24.7; postop 23.8 ± 21.6; p = .002); NIBUT (5.5 ± 2.6 s to 9.9 ± 6.8 s p = .08) and LLT (64.3 ± 30.4 to 74.1 ± 27.8; p = .025) improved, while Schirmer Test (15.3 ± 4.7 mm to 11.9 ± 2.9 mm; p = .03) and tear meniscus height were reduced (0.8 ± 0.3 to 0.6 ± 0.2; p = .05). Meibomian gland loss scored by the meiboscale slightly increased postoperatively (1.2 ± 0.9 to 1.4 ± 0.9; p = .18). The number of expressible Meibomian glands improved (4.4 ± 2.6 to 6.8 ± 2.1, p = .002) as well as the quality of Meibum (0.9 ± 1.0 to 0.5 ± 0.8, p = .04). Snap back test as well the pinch test were negative in all patients postoperatively.Conclusion: Addressing lower lid laxity with an LCS procedure simultaneously enhances tear drainage, reduces tear film volume parameters and increases tear film stability results with an improvement of dry eye symptoms. It is likely that increased lower eyelid tension and thus excretory pressure on the Meibomian glands is responsible for these alterations.

[Inflammation in Dry Eye Disease - Information on Diagnostic Testing and Therapy Using the Scientific Online Information Platform OSCB-Berlin.org]. / Entzündung beim Trockenen Auge ­ Informationen zu Diagnostik und Therapie durch Nutzung der wissenschaftlichen Online-Informationsplattform OSCB-Berlin.org.

Dry eye is considered the most common disease in ophthalmology. In recent decades, there has been intensive clinical and experimental research on this condition and our scientific knowledge of its pathophysiology has greatly expanded. The disease may be simple or severe and may lead to complex deregulation of the functional anatomy of the ocular surface, typically with a disparity between the clinical findings and the patient's symptoms. Chronic tissue injury induces various vicious circles that together lead to progressive worsening of the clinical picture. This can trigger inflammatory reactions that further intensify the disease process and can lead to the development of immunomodulated inflammation and a chronic pain syndrome. Both are relatively resistant to therapy in ordinary clinical practice. Better insight into the pathophysiological basics has enabled many approaches for innovations in diagnosis and therapy of dry eye. Nevertheless, sicca practice typically requires a great deal of time, usually offers only symptomatic therapy in everyday life and is often unsatisfactory for the patient and for his or her physician. For this reason, dry eye is often rather difficult to understand and difficult to manage. The scientific information platform of the Ocular Surface Center Berlin (OSCB-Berlin.org) aims to facilitate the understanding of the functional interactions at the ocular surface and thus also of the mechanisms involved in the complex pathophysiology of dry eye disease and of chronic inflammation. This is the basis for an up-to-date overview of dry eye diagnostic testing and therapy on different levels, which allows an understanding for clinicians and also for patients.

TFOS DEWS II pathophysiology report.

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

Growth Hormone Influence on the Morphology and Size of the Mouse Meibomian Gland.

Purpose. We hypothesize that growth hormone (GH) plays a significant role in the regulation of the meibomian gland. To test our hypothesis, we examined the influence of GH on mouse meibomian gland structure. Methods. We studied four groups of mice, including (1) bovine (b) GH transgenic mice with excess GH; (2) GH receptor (R) antagonist (A) transgenic mice with decreased GH; (3) GHR knockout (-/-) mice with no GH activity; and (4) wild type (WT) control mice. After mouse sacrifice, eyelids were processed for morphological and image analyses. Results. Our results show striking structural changes in the GH-deficient animals. Many of the GHR-/- and GHA meibomian glands featured hyperkeratinized and thickened ducts, acini inserting into duct walls, and poorly differentiated acini. In contrast, the morphology of WT and bGH meibomian glands appeared similar. The sizes of meibomian glands of bGH mice were significantly larger and those of GHA and GHR-/- mice were significantly smaller than glands of WT mice. Conclusions. Our findings support our hypothesis that the GH/IGF-1 axis plays a significant role in the control of the meibomian gland. In addition, our data show that GH modulates the morphology and size of this tissue.

Transcription, translation, and function of lubricin, a boundary lubricant, at the ocular surface.

IMPORTANCE: Lubricin may be an important barrier to the development of corneal and conjunctival epitheliopathies that may occur in dry eye disease and contact lens wear. OBJECTIVE: To test the hypotheses that lubricin (ie, proteoglycan 4 [PRG4 ]), a boundary lubricant, is produced by ocular surface epithelia and acts to protect the cornea and conjunctiva against significant shear forces generated during an eyelid blink and that lubricin deficiency increases shear stress on the ocular surface and promotes corneal damage. DESIGN, SETTING, AND PARTICIPANTS: Human, porcine, and mouse tissues and cells were processed for molecular biological, immunohistochemical, and tribological studies, and wild-type and PRG4 knockout mice were evaluated for corneal damage. RESULTS: Our findings demonstrate that lubricin is transcribed and translated by corneal and conjunctival epithelial cells. Lubricin messenger RNA is also present in lacrimal and meibomian glands, as well as in a number of other tissues. Absence of lubricin in PRG4 knockout mice is associated with a significant increase in corneal fluorescein staining. Our studies also show that lubricin functions as an effective friction-lowering boundary lubricant at the human cornea-eyelid interface. This effect is specific and cannot be duplicated by the use of hyaluronate or bovine serum albumin solutions. CONCLUSIONS AND RELEVANCE: Our results show that lubricin is transcribed, translated, and expressed by ocular surface epithelia. Moreover, our findings demonstrate that lubricin presence significantly reduces friction between the cornea and conjunctiva and that lubricin deficiency may play a role in promoting corneal damage.

Characterization of ocular gland morphology and tear composition of pinnipeds.

OBJECTIVE: The importance of tear film integrity to ocular health in terrestrial mammals is well established, however, in marine mammals, the role of the tear film in protection of the ocular surface is not known. In an effort to better understand the function of tears in maintaining health of the marine mammal eye surface, we examined ocular glands of the California sea lion and began to characterize the biochemical nature of the tear film of pinnipeds. PROCEDURES: Glands dissected from California sea lion eyelids and adnexa were examined for gross morphology, sectioned for microscopic analysis, and stained with hematoxylin and eosin. The tear film was examined using interferometry. Tears were collected from humans and pinnipeds for the analysis of protein and carbohydrate content. RESULTS: The sea lion has sebaceous glands in the lid, but these glands are different in size and orientation compared with typical meibomian glands of terrestrial mammals. Two other accessory ocular glands located dorsotemporally and medially appeared to be identical in morphology, with tubulo-acinar morphology. An outer lipid layer on the ocular surface of the sea lion was not detected using interferometry, consistent with the absence of typical meibomian glands. Similar to human tears, the tears of pinnipeds contain several proteins but the ratio of carbohydrate to protein was greater than that in human tears. CONCLUSIONS: Our findings indicate that the ocular gland architecture and biochemical nature of the tear film of pinnipeds have evolved to adapt to the challenges of an aquatic environment.

The lid wiper contains goblet cells and goblet cell crypts for ocular surface lubrication during the blink.

PURPOSE: The conjunctival side of the upper and lower inner eyelid borders, termed the lid wiper, has a thickened epithelial lip for apposition to the globe, assumed to distribute the preocular tear film. The human lid wiper structure and its goblet cells are investigated. METHODS: Conjunctival whole mounts, including lid margins from 17 eyes of human body donors, were investigated by routine histology and semithin plastic sections, using histology, histochemistry, and immunohistochemistry. RESULTS: In routine histology, the conjunctival lid wiper epithelium regularly showed goblet cells, single and in clusters, at the luminal surface and also deep within the epithelium without apparent surface contact. Semithin sections revealed that the deep goblet cells were often connected to cryptal epithelial infoldings that opened to the surface, hence making their mucins available at the surface. The goblet cells produced mucins of neutral (periodic acid-Schiff) and acidic (Alcian blue) type and stained positive for the gel-forming mucin MUC5AC. Surprisingly, MUC5AC-negative goblet cells were also observed in the lid wiper. CONCLUSIONS: Contrary to conventional assumptions, the lid wiper is part of the conjunctiva. It contains previously undescribed goblet cell crypts deep in the epithelium, suitable as an internal lubrication system for reduction of friction between the lid margin and the globe. This provides the first evidence of the morphological basis for the hydrodynamic type of lubrication and a more conclusive understanding of lid-margin lubrication and tear film distribution. It is another strong indication that the lid wiper is that area in apposition with the globe for distributing the thin preocular tear film during the blink.

The lid wiper and muco-cutaneous junction anatomy of the human eyelid margins: an in vivo confocal and histological study.

The inner border of the eyelid margin is critically important for ocular surface integrity because it guarantees the thin spread of the tear film. Its exact morphology in the human is still insufficiently known. The histology in serial sections of upper and lower lid margins in whole-mount specimens from 10 human body donors was compared to in vivo confocal microscopy of eight eyes with a Heidelberg retina-tomograph (HRT II) and attached Rostock cornea module. Behind the posterior margin of the Meibomian orifices, the cornified epidermis stopped abruptly and was replaced by a continuous layer of para-keratinized (pk) cells followed by discontinuous pk cells. The pk cells covered the muco-cutaneous junction (MCJ), the surface of which corresponded to the line of Marx (0.2-0.3 mm wide). Then a stratified epithelium with a conjunctival structure of cuboidal cells, some pk cells, and goblet cells formed an epithelial elevation of typically about 100 µm initial thickness (lid wiper). This continued for 0.3-1.5 mm and formed a slope. The MCJ and lid wiper extended all along the lid margin from nasal to temporal positions in the upper and lower lids. Details of the epithelium and connective tissue were also detectable using the Rostock cornea module. The human inner lid border has distinct zones. Due to its location and morphology, the epithelial lip of the lid wiper appears a suitable structure to spread the tear film and is distinct from the MCJ/line of Marx. Better knowledge of the lid margin appears important for understanding dry eye disease and its morphology can be analysed clinically by in vivo confocal microscopy.

About vital staining of the eye and eyelids. I. The anatomy, physiology, and pathology of the eyelid margins and the lacrimal puncta by E. Marx. 1924.

This article is a translation of the original article authored by Eugen Marx and published in 1924.1 Amazingly, many of the issues addressed in the 1924 publication are now, >80 years later, of prime interest for both understanding the lid margin and ocular surface and thus for dry eye diagnosis and treatment. To assist the reader and possibly to provoke further contemplation on a particular section of the translation, we have inserted comments, identified throughout the text. All references, in their original format, have been included in this translation, except those referred to in a few paragraphs that were not readily understood in today's technical language and which were omitted. The first figure of the original article is not included in this translation because it was referred to in one of the few omitted paragraphs.

Regulation of the inflammatory component in chronic dry eye disease by the eye-associated lymphoid tissue (EALT).

PURPOSE: The physiologically protective mucosal immune system of the ocular surface consists of lymphocytes, accessory leukocytes and soluble immune modulators. Their involvement has also been observed in inflammatory ocular surface diseases, including dry eye syndrome, and we have attempted here to describe their interaction. METHODS: Our own results regarding the mucosal immune system of the human ocular surface are discussed together with the available literature on mucosal immunity and inflammatory ocular surface disease. RESULTS: The mucosa of the ocular surface proper (conjunctiva and cornea) is anatomically continuous with its mucosal adnexa (the lacrimal gland and lacrimal drainage system) and contains a mucosal immune system termed 'eye-associated lymphoid tissue' (EALT). This extends from the periacinar lacrimal-gland-associated lymphoid tissue along the excretory ducts into the conjunctiva-associated lymphoid tissue (CALT) and further into the lacrimal drainage-associated lymphoid tissue (LDALT). EALT consists of continuous diffuse lymphoid effector tissue and of interspersed follicles for effector cell generation in CALT and LDALT. Typical events in ocular surface disease include alteration and activation of epithelial cells with loss of epithelial integrity, production of inflammatory cytokines, and potential presentation of non-pathogenic and self-antigens - leading to a loss of immune tolerance. Events in the deregulation of physiologically protective EALT, resulting vicious circles, and eventual self-propagating immunomodulated inflammatory disease processes are explained, discussed and visualized by schematic drawings. CONCLUSION: Deregulation of EALT can orchestrate a self-propagating inflammatory mucosal disease process if the capacity of natural compensatory factors is overridden and if the disease is not limited by timely diagnosis and therapy.

The lid margin is an underestimated structure for preservation of ocular surface health and development of dry eye disease.

PURPOSE: The structure of the lid margin is insufficiently understood and defined, although it is of obvious importance in ocular surface integrity. METHODS: The structure and function of the different zones of the lid margin are explained with a focus on dry eye disease. RESULTS: The posterior lid margin, which is of particular significance for the integrity of the ocular surface, includes the meibomian glands that open within the cornified epidermis. Their obstructive dysfunction is a main cause of dry eye disease. The orifice is followed by the mucocutaneous junction, which extends from the abrupt termination of the epidermis to the crest of the inner lid border. The physiological vital stainable line of Marx represents its surface, and can be used e.g. as a diagnostic tool for the location and functionality of the meibomian gland orifices and lacrimal puncta. The marginal conjunctiva starts at the crest of the inner lid border and forms a thickened epithelial cushion. This is the point closest to the globe, and represents the zone that wipes the bulbar surface and distributes the thin preocular tear film. It is hence termed the 'lid wiper' and pathological alterations that result in a vital staining are a sensitive early indicator of dry eye disease. CONCLUSIONS: The margin of the eyelid is an important but currently underestimated structure in the maintenance of the preocular tear film and of the utmost importance for the preservation of ocular surface integrity and in the development of dry eye disease.

Corneal allograft endothelial cell replacement represents a reparative response to transplant injury.

PURPOSE: To elucidate the injury of corneal allograft endothelial cells (ECs) upon rejection and the subsequent replacement process of the cells. METHODS: The corneal transplantation model in an major histocompatibility complex (MHC) class I/II disparate Dark Agouti (DA)-Lewis combination was used. The rejection kinetics was observed in 16 cases in which the corneal opacity grade was recorded after grafting and after the onset of rejection. Four normal corneas and four allografts were subjected to EC staining to investigate the EC integrity in cases of rejection. Furthermore, a series of rejected allografts were examined and the EC integrity compared at one week, three weeks, three months, and six months after the onset of rejection. RESULTS: All corneal allografts were rejected, resulting in EC integrity loss. However, the allografts recovered transparency around 18 days after the onset of rejection with repaired endothelium by regenerative ECs. Moreover, although the whole endothelium would be fully recovered after rejection, the ratio of regenerative EC density reached only half of normal levels as long as six months after the transplant. CONCLUSIONS: Corneal allograft EC replacement represents a reparative response to transplant-related injury.

Local production of secretory IgA in the eye-associated lymphoid tissue (EALT) of the normal human ocular surface.

PURPOSE: Secretory IgA (SIgA) is a critical local defense mechanism of mucosal immunity. Although the conjunctiva, as part of the ocular surface, has a mucosa-associated lymphoid tissue, the production of SIgA by local plasma cells and its transport is unequivocally accepted to occur only in the upstream lacrimal gland (LG). The molecular components were therefore investigated by immunohistochemistry (IHC) and their local production verified by RT-PCR. METHODS: Tissues from 18 conjunctivas and 9 LGs of human donor eyes with normal ocular surfaces were analyzed by histology and IHC. Different zones of 12 further conjunctivas and LG tissues were analyzed by RT-PCR for the presence of the respective mRNA. RESULTS: Plasma cells were present in the diffuse lymphoid tissue of all investigated specimens and showed an intense immunoreactivity for IgA. This immunoreactivity was absent when the antiserum was preadsorbed with the protein. The luminal epithelium, with the exception of goblet and basal cells, was strongly positive for the epithelial transporter molecule secretory component (SC) in the conjunctiva and interconnecting excretory duct similar to the LG. PCR products for IgA, the monomeric IgA-joining molecule (J-chain) and SC were regularly found in all conjunctival zones and in the LG in gel electrophoresis and were sequenced. CONCLUSIONS: The local production of SIgA is for the first time verified by RT-PCR in the human conjunctiva and in the LG. This finding points to an active role of the conjunctiva in secretory immune protection of the ocular surface and supports the presence and importance of EALT at the normal ocular surface.

Anatomy and immunology of the ocular surface.

The ocular surface, in a strict sense, consists of the cornea and its major support tissue, the conjunctiva. In a wider anatomical, embryological, and also functional sense, the ocular mucosal adnexa (i.e. the lacrimal gland and the lacrimal drainage system) also belong to the ocular surface. This definition includes the source and the eventual drainage of the tears that are of utmost importance to ocular surface integrity. The ocular surface is directly exposed to the external environment, and therefore is endangered by a multitude of antigens and pathogenic microorganisms. As a mucosa, it is protected by the mucosal immune system that uses innate and adaptive effector mechanisms present in the tissue and tear film. Immune protection has two partly opposing tasks: the destruction of invading pathogens is counterbalanced by the limitation of inflammatory events that could be deleterious to the subtle structure of the eye. The immune system of the ocular surface forms an eye-associated lymphoid tissue (EALT) that is recognized as a new component of the mucosal immune system. The latter consists of the mucosa-associated lymphoid tissues in different organs of the body. Mucosa- and hence eye-associated lymphoid tissues have certain characteristics that discriminate them from the central immune system. The mechanisms applied are immunological ignorance, tolerance, or an immunosuppressive local microenvironment, all of which prefer non-reactivity and anti-inflammatory immunological responses. The interaction of these mechanisms results in immune privilege of the ocular surface. During eye closure, the ocular surface appears to have different requirements that make an innate pro-inflammatory environment more attractive for immune defense. The structural and functional components that contribute to this special immune regulation will be the focus of this chapter.

Ultrastructural anatomy of CALT follicles in the rabbit reveals characteristics of M-cells, germinal centres and high endothelial venules.

Conjunctiva-associated lymphoid tissue (CALT) is a part of the eye-associated lymphoid tissue (EALT) at the ocular surface. Its lymphoid follicles are usually characterized by using light microscopy, but its ultrastructure remains largely unknown. In this study, flat whole-mount conjunctival tissues (n = 42) from 21 young adult rabbits were investigated native in reflected light, and further stained and cleared (n = 6), in paraffin histology sections (n = 6), scanning electron microscopy (SEM, n = 4) and transmission electron microscopy (TEM, n = 4). Secondary lymphoid follicles accumulated into a dense group nasally towards the lacrimal punctum of the lower lid. High endothelial venules (HEV) with typical ultrastructure occurred in the parafollicular zone. The bright germinal centre (GC) contained lymphoblasts, follicular dendritic cells, apoptotic cells and tingible body macrophages. The follicle-associated epithelium (FAE) was devoid of goblet cells and contained groups of lymphoid cells. TEM showed these cells to be located in cytoplasmic pockets of superficial electron-lucent cells with a thin cytoplasmic luminal lining that contained a fine filament meshwork and numerous endocytotic vesicles. These M-cells were sitting between and on top of the ordinary dense epithelial cells that were located basally and formed pillar-like structures. In stereoscopic SEM, the surface cells were very large, had a polygonal outline and covered cavernous spaces. The rabbit has a CALT with typical follicular morphology, including HEV for regulated lymphocyte migration and epithelial cells with ultrastructural characteristics of M-cells that allow antigen transport as indicated by the GC-reaction. The arrangement of these M-cells on top of and between epithelial pillar cells may reflect a special structural requirement of the multilayered CALT FAE.