Tear Film Deficiency Research Articles

Ocular surface disorders: office procedures for the allergist/clinical immunologist.

Ocular surface disorders (OSDs) are a prevalent and often debilitating condition encountered in clinical practice, particularly by allergists and clinical immunologists. A comprehensive guide to office procedures for evaluating and managing OSDs, with a specific focus on ocular allergies, would assist in the evaluation process that begins with an initial patient assessment utilizing standardized forms to systematically gather detailed medical history, symptomatology, and environmental exposure data. This structured approach ensures a thorough understanding of the patient's condition and facilitates targeted interventions. In addition to allergy testing, the assessment of the tear film is essential for a comprehensive evaluation of OSDs. The Schirmer test is employed to quantify tear production, providing objective data on tear film adequacy and guiding interventions for tear film deficiencies. This multifaceted diagnostic approach ensures that all contributing factors to OSDs are identified and appropriately managed. By integrating these office procedures, allergists and clinical immunologists can enhance their diagnostic accuracy and therapeutic efficacy, ultimately improving patient outcomes. This manuscript provides a practical resource, outlining some of the methodologies and clinical applications of each procedure, and highlighting their role in the holistic management of OSDs in allergic patients.

The bioengineering application of hyaluronic acid in tissue regeneration and repair

The multifaceted role of hyaluronic acid (HA) across diverse biomedical disciplines underscores its versatility in tissue regeneration and repair. HA hydrogels employ different crosslinking including chemical (chitosan, collagen), photo- initiation (riboflavin, LAP), enzymatic (HRP/H2O2), and physical interactions (hydrogen bonds, metal coordination). In biophysics and biochemistry, HA's signaling pathways, primarily through CD44 and RHAMM receptors, modulate cell behavior (cell migration; internalization of HA), inflammation, and wound healing. Particularly, smaller HA fragments stimulate inflammatory responses through toll-like receptors, impacting macrophages and cytokine expression. HA's implications in oncology highlight its involvement in tumor progression, metastasis, and treatment. Elevated HA in tumor stroma impacts apoptosis resistance and promotes tumor growth, presenting potential therapeutic targets to halt tumor progression. In orthopedics, HA's presence in synovial fluid aids in osteoarthritis management, as its supplementation alleviates pain, enhances synovial fluid's viscoelastic properties, and promotes cartilage integrity. In ophthalmology, HA's application in dry eye syndrome addresses symptoms by moisturizing the eyes, replenishing tear film deficiencies, and facilitating wound healing. Intravitreal injections and hydrogel-based systems offer versatile approaches for drug delivery and vitreous humor replacement. For skin regeneration and wound healing, HA hydrogel dressings exhibit exceptional properties by promoting moist wound healing and facilitating tissue repair. Integration of advanced regenerative tools like stem cells and solubilized amnion membranes into HA-based systems accelerates wound closure and tissue recovery. Overall, HA's unique properties and interactions render it a promising candidate across diverse biomedical domains, showcasing immense potentials in tissue regeneration and therapeutic interventions. Nevertheless, many detailed cellular and molecular mechanisms of HA and its applications remain unexplored and warrant further investigation.

Ressecamento ocular em terapia intensiva: proposta de novo diagnóstico de enfermagem

ABSTRACT Objective: to analyze the concept associated with diagnostic proposition Ocular dryness in adult patients hospitalized in an Intensive Care Unit, identifying its attributes, antecedents and consequences. Methods: a methodological study carried out through concept analysis, operationalized by scoping review. Results: the analysis of 180 studies allowed the identification of two attributes, 32 antecedents and 12 consequences. The attributes were tear film deficiency and ocular signs and/or symptoms. The prevalent antecedents were incomplete eyelid closure (lagophthalmos) and blinking mechanism decrease. Major consequences included conjunctival hyperemia and decreased tear volume. Conclusions: this study allowed constructing nursing diagnosis Ocular dryness, part of domain 11, class 2, with 12 defining characteristics, 12 related factors, seven populations at risk and 13 associated conditions. This problem-focused proposal may provide targeted care by promoting early detection and implementing interventions that reduce the risk of ocular damage.

A review of diagnostic tests for qualitative and quantitative tear film deficiency in dogs.

Dry eye disease (DED) is a complex multifactorial condition caused by loss of ocular surface homeostasis from quantitative and/or qualitative tear film deficiency. Schirmer tear test (STT) is often the only diagnostic test used to assess for DED in veterinary practice. STT is invaluable in the diagnosis and monitoring of quantitative tear film deficiency (i.e., keratoconjunctivitis sicca); however, it is not sufficient to optimize therapy and fully recognize other contributing factors for the disturbance in ocular surface homeostasis. The present work reviews diagnostic tests for assessing aqueous tear production in veterinary medicine, as well as the quality of tears, corneal epithelial barrier integrity, and the lacrimal functional unit.

An eye on the Shih Tzu dog: Ophthalmic examination findings and ocular surface diagnostics.

To characterize the ocular surface parameters and determine the prevalence of ocular pathology in Shih Tzu dogs. Fifty Shih Tzu dogs (28 male, 22 female). Each dog underwent a complete ophthalmic examination (recording any pathology) and a series of diagnostics, allowing for a 10min-interval between tests: intraocular pressure (IOP), blink rate, palpebral fissure length (PFL), corneal tactile sensation (CTS), Schirmer tear test and nasolacrimal reflex without (STT-1, NL-STT1) and with topical anesthesia (STT-2, NL-STT2), tear ferning, strip meniscometry test (SMT), tear film breakup time (TFBUT), and punctate fluorescein staining (PFS) of the cornea. Mean ± SD test values were as follows: IOP (17.9 ± 3.7 mmHg), blink rate (2.4 ± 1.4 blinks/min), PFL (23.8 ± 1.8 mm), CTS (1.8 ± 0.7cm), STT-1 (22.0 ± 5.5 mm/min), NL-STT1 (24.2 ± 4.7 mm/min), STT-2 (16.9 ± 6.5 mm/min), NL-STT2 (18.5 ± 7.5 mm/min), SMT (7.5 ± 3.5 mm/5s), TFBUT (5.3 ± 2.4s), tear ferning (1.3 ± 0.7), and PFS (1.6 ± 0.6). PFL was significantly greater in male vs. female Shih Tzus (p< .001). Age was negatively correlated with TFBUT results (r=-0.31, p=.027). Lagophthalmos was observed in 82% eyes. Ocular surface pathology was common, including adnexal abnormalities (100% eyes with caruncular trichiasis and medial lower lid entropion) and corneal opacification (27% pigmentation, 20% fibrosis, 12% neovascularization). Qualitative tear film deficiency (low TFBUT), along with several anatomical abnormalities that promote ocular irritation and reduce globe protection, together help explain the concerningly high prevalence of ocular surface disease in the Shih Tzu breed. Prophylactic measures (e.g., medial canthoplasty, topical lubrication) could be considered to improve ocular health in Shih Tzus.

Altered Corneal Innervation and Ocular Surface Homeostasis in FHV-1-Exposed Cats: A Preliminary Study Suggesting Metaherpetic Disease.

Metaherpetic disease is recognized in humans affected by herpes simplex virus-1 but is not reported in cats affected by feline herpesvirus-1 (FHV-1) despite the high prevalence of herpetic disease in this species and strong similarities in viral biology between alphaherpesviruses of humans and cats. This preliminary work evaluated cats naïve to FHV-1 (n = 9 cats, 18 eyes; control population) and cats naturally exposed to FHV-1 (n = 4 cats, 7 eyes), as confirmed by serologic testing and review of medical records. Antemortem assessment included clinical scoring, blink rate, corneal aesthesiometry, tear film breakup time (TFBUT), and Schirmer tear test-1 (STT-1) with or without the nasolacrimal reflex. Post-mortem assessment involved confocal microscopy of the corneas and evaluation of corneal nerves with ImageJ. Groups were compared with Student's t-tests and results are presented as mean ± standard deviation. Compared to control, herpetic cats had significantly higher (P ≤ 0.010) clinical scores (0.2 ± 0.4 vs. 4.6 ± 2.8) and response to nasolacrimal stimulation (7.8 ± 10.8% vs. 104.8 ± 151.1%), significantly lower (P < 0.001) corneal sensitivity (2.9 ± 0.6 cm vs. 1.4 ± 0.9 cm), STT-1 (20.8 ± 2.6 mm/min vs. 10.6 ± 6.0 mm/min), TFBUT (12.1 ± 2.0 s vs. 7.1 ± 2.9 s), and non-significantly lower blink rate (3.0 ± 1.5 blinks/min vs. 2.7 ± 0.5 blinks/min; P = 0.751). All parameters evaluated for corneal nerves (e.g., nerve fiber length, branching, occupancy) were notably but not significantly lower in herpetic vs. control cats (P ≥ 0.268). In sum, cats exposed to FHV-1 had signs suggestive of corneal hypoesthesia and quantitative/qualitative tear film deficiencies when compared to cats naïve to the virus. It is possible these are signs of metaherpetic disease as reported in other species.

The use of tear ferning test in cats for evaluation of ocular surface

BackgroundThe tear film is a trilaminar fluid composed mainly of lipids, electrolytes, proteins and water. It is responsible for lubrication, nutrition and protection against microbial and toxic agents. Disruption of any these components may weaken the ocular surface, making it more susceptible to disease. Increasing evidence suggests that qualitative tear film deficiencies are an important predisposing factor or cause of some of the most common and challenging ocular diseases in cats, including conjunctivitis, corneal ulcer, spontaneous chronic corneal epithelial defects (SCCED), pigmentary keratitis, corneal sequestrum and dry eye syndrome. The aim of this study was to describe the tear ferning test in healthy cats and to compare the results by using two grading scales for humans. Tear samples were collected using Schirmer tear test (STT) strips from 60 healthy cats, and, after centrifuging the strips to obtain the samples, the aliquot was placed on clean microscope glass until it dried and the tear ferning patterns were observed under a polarized light microscope and classified according to the Rolando and Masmali grading scales.ResultsFerning patterns in the lower grades showed full crystallization with high density, without gaps between the ferns and branches, forming several nuclei that were easily distinguished. According to the Rolando scale, 50% (60/120), 46.6% (56/120) and 3.4% (4/120) of eyes showed type I, II and III patterns, respectively. According to the Masmali scale, 15% (18/120), 56.6% (68/120 eyes) and 28.4% (34/120) of eyes showed grade 0, 1 and 2 patterns, respectively. No difference was observed between the right and left eyes for both Rolando (P = 0.225) and Masmali (P = 0.683) scales.ConclusionsThe tear ferning test is a qualitative test that can be used in cats as a complementary evaluation of the ocular surface. While the Rolando scale showed an increased prevalence of types I and II, the Masmali scale showed an increased prevalence of grades 1 and 2. This can be attributed to the species-specific differences between human and feline tear film. So Masmali grade 2 can be considered a normal tear pattern for the species, because all the cats used in study were clinically healthy. For this reason, future complementary studies are necessary for comparing healthy eyes and eyes with different ocular surface disease in cats. Both scales can be feasible options for grading tear crystallization in cats, but as Rolando scale included 96.6% of the samples in the 2 types that are considered normal for humans, we think that this scale seemed to be more precise to classify crystallization pattern in cats. The crystallization patterns observed in this study can form the basis for standardizing ocular surface parameters in cats.

Evaluation of partial tarsal plate excision using a transconjunctival approach for the treatment of distichiasis in dogs.

To evaluate the clinical outcome, possible complications, and recurrence rate of distichiasis in dogs treated with partial tarsal plate excision (PTPE) technique using a transconjunctival approach. Retrospective study including 17 client-owned canine patients affected with distichiasis and presenting with associated clinical signs (ie, blepharospasm, epiphora, chronic keratoconjunctivitis, or corneal ulceration) that underwent surgical removal of the aberrant lashes using a PTPE technique between January 2018 and February 2019. Data collected included breed, age, sex, affected eyelid(s), number of distichia, and tear film breakup time (TBUT). Resected cilia-bearing tarsoconjunctival strips were submitted for histopathological analysis. Thirty eyes (52 eyelids) from 17 dogs were included in the study. The median age was 688days (range 118-4243days). A successful outcome, defined as complete resolution of clinical signs attributable to the distichia, occurred in all eyes after a single procedure, with a mean follow-up time of 239days (range 69-480days). Appearance of new distichia occurred in 14/30 eyes (46.3%), and of these, three eyes needed a new PTPE procedure. Recurrence of the distichia only occurred in one eye (3.3%) which was asymptomatic. Following surgery, TBUT decreased below the normal value in 7/24 eyes (29.1%) although none developed clinical signs of qualitative tear film deficiency. Post-operative complications included trichiasis and cicatricial entropion, which developed in two eyes (6.6%), and these were successfully managed with corrective eyelid surgery. Partial tarsal plate excision, using a transconjunctival approach, had an excellent clinical outcome with a low incidence of complications.

Osmokinetics: A new dynamic concept in dry eye disease

Tear fluid osmolarity has been increasingly accepted as an accessible parameter in the diagnosis of ocular surface and dry eye disease. After having been proposed as the gold standard, recent results have put this into question. However, the most recent guidelines for dry eye disease identify specific values of osmolarity as thresholds to help to differentiate between various stages of severity of ocular surface disease. The limits of this approach were investigated to propose a new concept, that of osmokinetics. Available data on tear fluid osmolarity in normal and diseased eyes were compared. The possibility of normo-osmolar dry eye was investigated and repeated measurements of osmolarity performed. The currently applied static model of a threshold value of osmolarity for diagnosing dry eye disease is apparently insufficient. Not only does it not take into account normo-osmolar dry eye, but it also applies too much significance to a single parameter. Instead, it was found that there is a daily variation in osmolarity (DVO), which appears to be higher in eyes with tear film deficiencies than in healthy eyes. Tear film osmolarity does vary considerably throughout the day. Its value should be considered in a kinetic model taking into account the dynamics of osmolarity changes moreso than the current static model. The terms of osmotic stress and diurnal variation of osmolarity were found to offer a more physiological understanding of osmolarity. A more dynamic model for osmolarity is presented in which not the value itself but the daily variation of osmolarity is identified. It is suggested that the amplitude of change in osmolarity over the course of a day or even shorter time periods could play a decisive role as a stress factor for the surface cells. The varying osmolar stress could be one of the key mechanisms leading to the cell death, inflammation, apoptosis, and goblet cell disappearance as observed in dry eye disease. Perhaps it is the mean osmolarity level at which these changes occur together with the magnitude of DVO which could identify the level of severity of dry eye disease.

Evaluation of transconjunctival thermal electrocautery for treatment of canine distichiasis: 88 eyelids (2013-2016).

To describe a successful, simple treatment for canine distichiasis. Client-owned dogs presenting to Veterinary Specialty and Emergency Center, Levittown, Pennsylvania. Retrospective analysis of medical records for canine patients that underwent transconjunctival thermal electrocautery treatment (TCEC) for distichiasis alone or with concurrent eyelid surgery between 2013 and 2016. Fifty eyes of 26 dogs (n = 88 eyelids) were included in the study. Sixty-five eyelids (74%) were treated for distichia only, while 23 eyelids (26%) underwent concurrent eyelid surgery. Successful treatment was defined as resolution of clinical signs attributable to distichiasis. Forty-eight of 50 eyes (96%) were successfully treated with a single TCEC treatment (mean follow-up 187 ± 222 days). Sixty-one of 88 eyelids (69%) had no distichia at any follow-up time. Twenty-two eyelids (25%) had recurrence at or near a previously treated site (mean 150 ± 152 days). Of the eyes with recurrent distichia, all but 2 (91%) remained asymptomatic, requiring no further treatment. One dog with extensive TCEC treatment had significant recurrence on all eyelids requiring retreatment that resulted in focal entropion of 1 eyelid. Transient eyelid margin pigment loss and mild-to-moderate eyelid swelling were noted in all treated eyelids postoperatively. Suspected treatment site infection occurred 2 days postoperatively in 2/50 eyes (4%) of 1 patient. Two of 10 eyes (20%) with extensive eyelid treatment developed qualitative tear film deficiency OU (554 days postoperatively) and responded to topical tear stimulant therapy. TCEC is a successful, simple treatment for canine distichiasis.

Substitution therapy for tear film deficiency

Substitution therapy for tear film deficiency

A holistic dynamic concept on dry eye disease identifies several different interacting self‐enforcing vicious circles of disease progression

PurposeDry Eye Disease (DED) is a complex alteration of the ocular surface. Typical are self‐enforcing mechanisms that drive the condition are termed ′Vicious Circles′ (VC). It is generally believed that ′a vicious circle′ occurs in DED that is driven by inflammation .MethodsA NLM PubMed based review of the literature review was performed and pathogenetic mechanisms were analyzed according to patho‐physiology.ResultsThis approach in DED indicates that Basic primary causative factors are (A) deficiency of tear SECRETION by the ocular secretory glands (aqueous lacrimal gland, oily Meibomian glands, single conjunctival goblet cell mucin glands) and (B) deficiency in FORMATION of a stable tear FILM by the eye lids &amp; blinking. The two main pathologies are (1) tear film deficiency and (2) tissue damage. Several VC in DED were identified: One important VC is destruction of the surface epithelium by insufficient wetting due to a deficient tear film which, in turn, further reduces the tissue wettability and thus tear film stability. Surface destruction leads to induction of inflammatory pathways that drive VS for progression of disease. Since the destruction of the tissue also impairs the ocular glands, large VC of gland destruction (Pathological Carousels) occur wherein tissue destruction increasingly impairs gland secretion which, in turn, drives further surface destruction. Other VC are hidden in the gland pathology of Meibomian Gland Dysfunction (MGD) and Lacrimal Gland Dysfunction (LGD).ConclusionsA holistic dynamic analysis of DED can identify, In contrast to present over‐simplified models, that Vicious Circles do not necessarily depend on inflammation and that there are in fact several, different, interacting vicious circles instead of just one. The relevant VC must be identified in the individual patient to allow an effective therapy.

A holistic dynamic concept on the pathophysiology in dry eye disease

AbsrtactPurposeDry Eye Disease (DED) is still insufficiently understood because it is a complex alteration of the functional anatomy of the ocular surface. Current concepts are often oversimplified and a new realistic model is developed that reflects all relevant aspects.Methods. A NLM PubMed based review of the literature on DED was performed. Pathogenetic mechanisms were identified and arranged in a patho‐physiologic hierarchy of causative relations that reflects clinical findings but is independent of assumed ′importance′.ResultsBasic primary causative factors for DED are structural and functional alterations of the ocular surface integrity. This concerns a deficiency of (A) tear component SECRETION by the secretory elements and of (B) tear FILM FORMATION by the eye lids and blinking mechanism. Together this leads to the two main pathologies of (1) TEAR FILM DEFICIENCY and thus insufficient permanent wetting of the interpalpebral surface that causes (2) the well‐known SURFACE TISSUE DAMAGE that gives rise to signs and symptoms. Both pathologies are governed by several interacting secondary pathogenetic factors. Typical for the complex disease mechanism are self‐enforcing vicious circles ‐ in contrast to present over‐simplified models they do not necessarily depend on inflammation and there are in fact several, different, interacting vicious circles instead of just one. The disease process is influenced by an impairment of regulatory systems (innervation, endocrine system, immune system) of the body &amp; by negative internal and external risk factors.ConclusionsThis new holistic dynamic concept on the pathophysiology DED incorporates long established as well as new mechanisms in the pathophysiological order. It is complex but not complicated ‐ intuitively understandable and suitable to assist basic scientist, patients, and clinical practitioner alike.

A Review of Ocular Graft-Versus-Host Disease.

: Graft-versus-host disease (GVHD) is a major complication that occurs following allogeneic hematopoietic stem cell transplantation, which is a potential curative therapy used in a variety of malignant or benign hematological diseases. Graft-versus-host disease primarily occurs in many organs, but most notably in the skin, lungs, gastrointestinal tract, liver, eyes, mucosa, and musculoskeletal system. Ocular manifestations of GVHD may precede other systemic GVHD findings, and it may be a poor prognosis for mortality. While all parts of the eye may be affected, ocular GVHD occurs primarily in the ocular surface. Dry eye disease or keratoconjunctivitis sicca is the most common presenting manifestation of chronic ocular GVHD. Dry eye disease in ocular GVHD is a multifactorial process, which involves destruction and fibrosis of lacrimal glands and conjunctiva, leading to tear film deficiency and instability. Depending on the severity of ocular involvement and response to treatment, ocular GVHD may cause decreased quality of life. Management of GVHD begins with prevention by understanding risk factors and by implementing prophylactic treatment after allogeneic hematopoietic stem cell transplantation. A multidisciplinary approach to the prevention and treatment of GVHD is important, and there are currently no preventive therapies available for ocular GVHD. Once diagnosed, ocular GVHD treatment strategies target ocular surface lubrication and support, tear film stabilization, inflammation reduction, and surgical intervention. The goal of this review is to define ocular GVHD and its categorical manifestations, as well as to describe the importance of comprehensive assessment, diagnosis, and ophthalmologic treatment and management of ocular GVHD with a multidisciplinary approach.

In vivo confocal microscopic evaluation of corneal langerhans cells in dry eye patients.

Purpose. To assess inflammatory involvement of cornea in dry eye by means of confocal microscopy, evaluating the presence and distribution of Langherans cells (LCs).Methods: 98 eyes of 49 subjects were enrolled: 18 subjects affected by Sjögren Syndrome Dry Eye (SSDE), 17 with Non-Sjögren Syndrome Dry Eye (NSSDE), 14 healthy volunteeers. Dry eye symptoms, tear film, ocular surface damage and corneal confocal microscopy were analized.Results: A significant increase of LCs density was observed at sub-basal nerve plexus (SSDE = 79 cells/mm2 andNDE = 22 cells/mm2; p = 0,0031) and sub-epithelial nerve plexus (SSDE = 38 cells/mm2 and NDE = 3 cells/mm2; p = 0,0169) in central cornea of SSDE group. An increased number of LCs from the center to the periphery of the cornea was observed, significant only in healthy volunteers group. In dry eye patients there was an increase in LCs density in both peripheral and central cornea with a significant difference between NDE (14,66 cells/mm2) and SSDE (56,66 cells/mm2) only in central cornea (p = 0,0028). In SSDE group, mean density of LCs in central cornea results also superior to NSSDE group (29,33 cells/mm2).There was no correlation between LCs density and dry eye symptoms, tear film deficiency and ocular surface damage.Conclusion: This study demonstrates the activation of an inflammatory and immunological reaction in cornea of NSSDE and SSDE patients. Confocal microscopy can be an important diagnostic tool in evaluation and follow-up of dry eye disease.

New therapeutic approaches and challenges for the treatment of dry eye disease

AbstractInnumerable individuals suffer from tear film dysfunctions, which are collectively diagnosed as dry eye disease (DED). In the United States alone DED afflicts tens of millions of people, especially women, and is one of the most frequent causes of patient visits to eye care practitioners. DED is characterized by a vicious cycle of tear film hyperosmolarity and instability and ocular surface stress, leading to increased friction, inflammation and damage to the eye. DED is caused primarily by meibomian gland dysfunction, and is associated with significant pain, decreased vitality and poorer general health. Because of diminished worker productivity, the burden of DED for the United States is estimated to be over $55.4 billion. There is no safe and effective global treatment for DED, and its therapy remains a profound unmet need throughout the world. A virtual kaleidoscope of new therapeutic approaches have been proposed to treat the mucin, aqueous and/or lipid tear film deficiencies, as well as the ocular surface damage, associated with DED. My presentation will highlight these approaches, and also address the significant clinical endpoint challenges that serve as barriers to the successful development of potential treatments for DED. Commercial interest

Development and evaluation of animal models for sex steroid deficient dry eye

Purpose: The present study was conducted to develop animal models to mimic postmenopausal/androgen deficiency dry eye and to evaluate the expression of sex steroid receptors (NR3A1, NR3A2 and NR3C4) in the ocular tissues of the developed models. Methods: The study was conducted in healthy Wistar rats of either sex weighing 180–250g. Bilateral ovariectomy was performed in female rats and oral finasteride (dose of 1.16mg/kg/day) challenge was given to both male and female rats. Along with time tear film stability was assessed by using cotton thread method and tear breakup time (TBUT). Dew point calculation was done using August–Roche–Magnus approximation during the tear assessments to correlate environmental factors affecting the tear function tests. At the end, animals were sacrificed and ocular tissues (lacrimal gland and cornea) were subjected for the quantification of the expression of NR3A1 (ER-α), NR3A2 (ER-β) and androgen (NR3C4) receptors. Results: The impact of ovariectomy caused a significant tear film deficiency from the 20th day onwards in all female rats. The ten day finasteride administration also showed a significant tear film deficiency in both male and female rats. However, subjecting 60days post ovariectomy rats to finasteride challenge did not show any further decrease in tear flow. Gene expression analysis also revealed a significant downregulation of sex steroid receptors in ocular tissues after ovariectomy and finasteride challenge. Discussion and conclusion: From this study, it has been concluded that ovariectomized and finasteride treated antiandrogenic models produced a significant tear deficiency in the rats which can be explored for pharmacological screening of topical agents and understanding the disease process in postmenopausal and androgen deficiency dry eye disorders.

Goblet cells in the conjunctival lid wiper elevation provide a built‐in lubrication system

AbstractPurpose The lid wiper is an epithelial elevation at the posterior lid border apposed to the globe that distributes the thin pre‐ocular tear film during the blink. To minimize the high risk of friction it can be assumed that it is provided with an advanced lubrication system.Methods The structure of the lid wiper epithelium is explained together with an overview of historical reports. Theoretical models of lubrication at the lid‐bulbus interface are discussed.Results A thickened epithelium was described early but the immediate functional implications for the distribution of the preocular tear film over the bulbar surface were noticed only much later. More recently “Lid wiper epitheliopathy” (LWE), a respective vital stainable epithelial alteration, was reported as first sign of tear film deficiency and increased friction in dry eye patients. The structure of the lid wiper was generally assumed to consist of a squamous non‐cornified epithelium, however in recent investigations we could show that it has in fact a conjunctival structure with goblet cells and goblet cell crypts that secrete mucins of different types.Conclusion The conjunctival structure of the lid wiper for distribution of the thin pre‐ocular tear film with goblet cells and goblet cell crypts implies the presence of a thick mucin‐water gel at the surface. This provides the structural pre‐requisite for the assumption of a hydrodynamic type of lubrication and can explain how the lid margin continuously travels over the bulbar ocular surface without wounding it. Support: DFG KN 317‐11

Ocular surface disorder in pterygium: Role of conjunctival impression cytology

To study ocular surface abnormalities in patients with pterygium, conjunctival impression cytology was explored as a tool for the assessment of the cytological changes. A comparative case control study was undertaken to evaluate the ocular surface disorders in pterygium. Fifty cases of pterygium and 50 age and sex-matched controls were analyzed for the presence of local tear film abnormalities as assessed by the tear film break up time and Schirmer test. The spectrum of changes in cytomorphology was studied in detail using conjunctival imprint cytology. Tear film break-up time and Schirmer's strip wetting were found to be significantly different in study and control groups. Studying the cytomorphology of the conjunctival imprint smears, reduced cellularity and squamous metaplasia of different grades was observed more frequently in patients compared to controls. On overall grading of cytological changes, statistically significant difference was noted between the study and control groups (P value 0.00172). From the present study we can suggest that aqueous tear film deficiency leading to ocular surface disorder brings about a change at the cytological level, and ocular surface disorders found in pterygium can be interpreted by conjunctival impression cytology.

Schirmer tear test values and tear film break‐up times in cats with conjunctivitis

(1) To document tear film break-up time (TFBUT) in a group of cats with conjunctivitis; (2) to determine if TFBUTs from cats with conjunctivitis vary significantly from previously established normal values for TFBUT in young cats without ocular disease; (3) to determine if a correlation exists between Schirmer tear test (STT) values and TFBUTs in cats with conjunctivitis; (4) to determine if the TFBUTs in cats with conjunctivitis are influenced by the detection of DNA from feline herpes virus-type 1 (FHV-1), Chlamydophila felis, Mycoplasma spp., and feline calicivirus. Fourteen cats between the ages of 0.8 years to 12 years with active, untreated conjunctivitis and without active keratitis or other ocular or systemic abnormalities were included in this study. Procedures Complete ophthalmic examinations, including TFBUT, were performed on all cats. Polymerase chain reaction (PCR) screening for FHV-1, Chlamydophila felis, Mycoplasma spp., and feline calicivirus was performed on conjunctival swabs from affected eyes and blood samples from all cats. Mean TFBUT for cats in this study was 8.9 (+/- 4.8) s in the right eye (OD) and 8.1 (+/- 4.6) s in the left eye (OS). No correlation existed between mean TFBUTs and mean STT values OD or OS. Conjunctival swabs from seven cats (n = 9 eyes) tested positive via PCR for one of the above infectious agents. Blood samples from nine cats tested positive for FHV-1. Mean TFBUTs for cats from which the DNA from FHV-1 was isolated from the blood were significantly lower than mean TFBUTs for cats from which no such DNA was isolated from the blood. In this study, the mean TFBUT in cats with conjunctivitis was significantly lower than previously established values for clinically healthy cats. This supports the theory that qualitative tear film deficiency, and thus tear film instability, may play a role in the pathogenesis of feline conjunctivitis. Qualitative tear film deficiency may predispose to the development of conjunctivitis or may occur secondarily to this condition.