The Potential Role of SP-G as Surface Tension Regulator in Tear Film: From Molecular Simulations to Experimental Observations.

The ocular surface is in constant interaction with the environment and with numerous pathogens. Therefore, complex mechanisms such as a stable tear film and local immune defense mechanisms are required to protect the eye. This study describes the detection, characterization, and putative role of surfactant protein G (SP-G/SFTA2) with respect to wound healing and surface activity. Bioinformatic, biochemical, and immunological methods were combined to elucidate the role of SP-G in tear film. The results show the presence of SP-G in ocular surface tissues and tear film (TF). Increased expression of SP-G was demonstrated in TF of patients with dry eye disease (DED). Addition of recombinant SP-G in combination with lipids led to an accelerated wound healing of human corneal cells as well as to a reduction of TF surface tension. Molecular modeling of TF suggest that SP-G may regulate tear film surface tension and improve its stability through specific interactions with lipids components of the tear film. In conclusion, SP-G is an ocular surface protein with putative wound healing properties that can also reduce the surface tension of the tear film.

[What is Important in Diagnosing Dry Eye Disease - Recommendations According to current Guidelines (DEWS II, DOG/BVA)]. / Was ist bei der Diagnostik des Trockenen Auges zu beachten?

Dry Eye is one of the most common ocular diseases worldwide with an increasing number of patients. The pathogenesis of this disease is multifactorial and complex and the basis for diagnostic strategies and therapies. The current definition of dry eye disease as described in DEWS II includes inflammatory mechanisms at the ocular surface, a loss of homeostasis, hyperosmolarity of the tear film and neurosensory abnormalities. Subject symptom scores, a detailed patient history, certain diagnostic tools, and interdisciplinary interactions are necessary to enable an efficient, individualized and successful therapy. Important diagnostics include risk factor analysis, slit lamp examination, tear secretion tests, tearfilm stability tests, and tests for measuring the ocular surface inflammation.

[Assessment of Langerhans Cells in the Central Cornea as Tool for Monitoring Inflammatory Changes in Patients with Keratoconjunctivitis sicca under Topical Therapy with Cyclosporine A 0.05% Eye Drops]. / Messung der Dichte der Langerhans-Zellen als Verlaufsparameter bei Patienten mit Keratoconjunctivitis sicca unter topischer antiinflammatorischer Therapie mit Ciclosporin A 0,05% Augentropfen.

BACKGROUND: Keratoconjunctivitis sicca is one of the most common ocular diseases and is associated with a considerable decrease in the quality of life. It is accompanied by symptoms of discomfort, tear film instability, hyperosmolarity of the tear film, inflammation of the ocular surface and neurosensory abnormalities. It is still not clear yet if the density of Langerhans cells in the central cornea can be used for objective evaluation of the inflammation in the tear film and the ocular surface. PATIENTS AND METHODS: 47 patients (age 21 - 85 years, 13 male and 34 female patients) with moderate to severe keratoconjunctivitis sicca (according to the DEWS criteria severity level 2 - 3) were enrolled in this prospective, clinical trial. Patients were treated for 3 months with topical anti-inflammatory therapy with cyclosporine 0,05% eye drops twice daily. The following parameters were examined: OSDI Score, tear break-up time (TBUT), Schirmer test with anaesthesia, lid-parallel conjunctival folds (LIPCOF), in-vivo confocal microscopy with HRT II and RCM for evaluation of Langerhans cell density in the central cornea, visual acuity, tear film osmolarity and Meibomian gland dysfunction (MGD). RESULTS: After anti-inflammatory treatment, there was a significant reduction in the density of Langerhans cells (p ≤ 0.001**), an increase in TBUT (p ≤ 0.001**), as well as a significant decrease in tear film osmolarity (p ≤ 0.05*) and OSDI Score (p ≤ 0 001**). Visual acuity, MGD and Schirmer test did not change significantly. CONCLUSIONS: The results of this clinical trial show that topical anti-inflammatory therapy with cyclosporine A 0.05% eye drops in patients with moderate to severe keratoconjunctivitis sicca is effective in reducing inflammation of the ocular surface and the tear film, as well as in increasing the quality of life in these patients. Evaluation of Langerhans cell density in the central corneal epithelium by in vivo confocal microscopy is an effective objective diagnostic feature in monitoring anti-inflammatory therapy in patients with dry eye disease or other ocular surface pathologies.

[If Artificial Tears Aren't Enough. The Importance of Inflammatory Processes in Dry Eye Disease. Practical Aspects of an Anti-Inflammatory Therapy of Dry Eye Disease]. / Wenn Tränenersatzmittel nicht mehr ausreichen: die Bedeutung von Entzündungsprozessen beim Trockenen Auge. Praktische Aspekte einer antientzündlichen Therapie des Trockenen Auges.

Dry eye disease (DED) is a heterogenous disease of the ocular surface. Multiple pathogenetic factors are responsible for the disease process, but DED is generally linked to an increase in the osmolarity of the tear film and to inflammation of the ocular surface. The significance of inflammatory processes in DED is highlighted in the most recent definition of dry eye in the Dry Eye Workshop (DEWS). It is therefore critically important for the management of dry eye disease to understand the pathomechanisms and therapeutic options for the treatment of inflammatory processes. This review summarizes our current knowledge on Inflammation associated with DED and provides practical recommendations for the diagnosis and monitoring of the disease, as well as the use of currently available therapeutic options to counteract inflammation in DED.

Lacrimal and meibomian gland evaluation in dry eye disease: A mini-review.

Lacrimal and meibomian glands contribute to the aqueous and lipid components of tear film, respectively. Their evaluation remains central to diagnosing and managing dry eye disease (DED). The review discusses the differences and reliability of various diagnostic tests and commercially available devices used for DED diagnosis. Slit-lamp-based techniques are direct palpebral lobe and tear flow assessment, Schirmer test, meibum quality and expressibility, and evaluation of tear meniscus height. Non-invasive tear meniscus height (TMH), tear break-up time (TBUT), lipid layer thickness (LLT), and meibography are machine-based diagnostic tests. The structure-function correlation of the tear-producing glands gives more comprehensive details than either information alone. Many devices are available in the market, which make DED diagnosis an easy feat, but the tests should be interpreted keeping in mind the intra-observer and inter-observer repeatability. Also, the tear film displays a huge variability as per the environmental conditions and impact of blinking. Hence, the examiner should be well versed with the techniques and repeat the test two to three times to obtain an average reading, which is more reliable. The recommended sequence of tests for diagnosing DED is a dry eye questionnaire, TMH, LLT, NIBUT (FBUT if non-invasive test is unavailable but should be performed after osmolarity), tear osmolarity, meibography, and ocular surface staining. Invasive tests such as Schirmer should be performed after the non-invasive tear film diagnostic testing.

A Water-Free Omega-3 Fatty Acid Eye Drop Formulation for the Treatment of Evaporative Dry Eye Disease: A Prospective, Multicenter Noninterventional Study.

Purpose: NovaTears®+Omega-3 is a water-free eye drop solution with non-animal-derived omega-3 fatty acids. It allows to supplement omega-3 fatty acids directly in the tear film of patients with dry eye disease (DED). This post-market clinical follow-up (PMCF) study evaluated for the first time the effects on clinical signs and patient symptoms of DED, and safety and tolerability of NovaTears+Omega-3 (0.2%) eye drops, when used in accordance with its approved label. Methods: A prospective, multicenter, single-arm, uncontrolled, open-label observational cohort study was performed in patients suffering from symptoms of evaporative DED. Patients were treated 4 times daily bilaterally according to the instructions for use for 8 weeks, and standard of care clinical end points were assessed at baseline and follow-up. The trial was conducted at 2 investigational sites in Germany, Europe. Results: Thirty-six patients were included and 33 completed the study. NovaTears+Omega-3 (0.2%) showed clinically and statistically significant improvements in various clinical signs, such as total corneal staining, tear film break-up time, and Meibomian gland dysfunction (MGD) score, as well as in symptoms measured by Ocular Surface Disease Index (OSDI©) and visual analog scales over the 8-week treatment period with change from baseline P values all <0.0001. No worsening of any safety parameter (intraocular pressure, slit-lamp examination, visual acuity) was observed, and no adverse event was reported throughout the study. Conclusions: In this observational PMCF study, NovaTears+Omega-3 was safe and well tolerated. Treatment over an 8-week period resulted in significantly improved clinical signs and subjective symptoms in patients with evaporative dry eye. The study was registered at www.clinicaltrials.gov (NCT04521465).

Prolactin Inducible Protein, but Not Prolactin, Is Present in Human Tears, Is Involved in Tear Film Quality, and Influences Evaporative Dry Eye Disease.

Purpose: Decreased production of the aqueous component of the tear film is an important cause of the development of dry eye disease (DED). Tear production is influenced by hormones and hormone-like factors. Prolactin (PLR), a multifunctional pituitary gland hormone, is regularly present in the lacrimal gland of rats and rabbits. In humans, serum PLR concentration correlates with tear quality. To gain deeper insights of possible effects of PRL, prolactin receptor (PRLR) and prolactin inducible protein (PIP), we analyzed the three proteins in the human lacrimal apparatus and in reflex tears of healthy volunteers as well as patients suffering from DED. Methods: Gene expression of PRLR and PIP was analyzed by RT-PCR in cadaveric human lacrimal gland and ocular surface tissues, immortalized human corneal epithelial cells (HCE and hTEPI) and human Meibomian gland epithelial cells (HMGECs). At the protein level, the expression and localization of PRL, PRLR and PIP in formalin-fixed paraffin sections of the lacrimal apparatus were studied by immunohistochemistry. In addition, tear fluid from DED patients and healthy volunteers was analyzed by ELISA to determine the concentration of PRL and PIP. Results: RT-PCR analyses revealed gene expression of PRLR and PIP in human tissue samples of cornea, lacrimal glands, and eyelids, whereas only PIP, but not PRLR, was detectable in immortalized corneal epithelial cells. Immunohistochemistry revealed for the first time the expression and localization of PRL, PRLR, and PIP in human tissues of the lacrimal apparatus and at the ocular surface. PRL and PRLR were detectable in corneal epithelium, lacrimal glands, and Meibomian glands. Reflex tears from DED patients revealed significantly increased PIP concentrations, whereas PRL was undetectable in tears of DED patients and healthy volunteers. Conclusion: PRL, PRLR, and PIP are found in the lacrimal apparatus and on the ocular surface. PIP, but not PRL, is present in human tears and appears to be involved in the physiology of tear film quality. Our clinical data revealed that PIP may affect tear quality, but further functional analyses are needed to fully elucidate the effects of PRL and PIP-associated factors in tear secretion as well as in the connection of DED.

Different Approach to Manage Demodex Blepharitis - Initial and Maintenance Treatment.

PURPOSE/AIM OF THE STUDY: To evaluate the improvement of ocular signs and symptoms in patients suffering from Demodex blepharitis using a combined treatment approach: use of eyelid wipes impregnated with 2.5% terpinen-4-ol (T4O) and 0.2% hyaluronic acid (HA) in the initial treatment period and investigation of maintenance of the treatment effect with the use of eyelid cleansing wipes. MATERIALS AND METHODS: Fifty patients with Demodex blepharitis were treated in the initial treatment period with sterile eyelid T4O impregnated wipes for 28 days. In the following four-week maintenance period, 82% patients received sterile eyelid maintenance wipes, while 16% continued treatment with T4O impregnated wipes. Global ocular discomfort, adapted TOSS, SANDE score, and individual blepharitis symptoms were assessed by patients at day 28 and day 56. Ocular signs were evaluated by the investigator at the study visits. Investigator's assessment of the overall treatment performance, patient's assessment of treatment satisfaction, and tolerability were evaluated with questionnaires. RESULTS: All global ocular discomfort symptoms and disease specific symptoms assessed by patients as well as all parameters evaluated by the investigators significantly improved in the initial treatment period with the application of eyelid wipes impregnated with 2.5% terpinen-4-ol until day 28. The therapeutic effect was maintained or even improved during the maintenance period under administration of mainly eyelid maintenance wipes until day 56. Both products were well tolerated. No adverse events and no clinically relevant changes in visual acuity were observed during both periods. CONCLUSIONS: Once daily treatment with T4O impregnated eyelid wipes in the initial treatment period significantly improved the ocular symptoms and signs and reduced the mite count in patients with Demodex blepharitis within four-weeks administration. Subsequent maintenance treatment with maintenance wipes for another 4 weeks preserved or further intensified the treatment success. The products were well tolerated and were convenient to use.

Topical Omega-3 Polyunsaturated Fatty Acids for the Treatment of Dry Eye - Results from a Pilot Randomized Controlled Masked-Observer Study.

Purpose: To investigate the efficacy, safety and tolerability of topical omega-3 polyunsaturated fatty acids (PUFA) as an innovative treatment of dry eye disease (DED). Patients and Methods: In a pilot, multicenter, masked-observer, randomized, active-controlled, non-inferiority study in Germany, patients self-treated their eyes with daily instillations of eye drops containing either omega-3 PUFA or povidone as major components for three months. At four and twelve weeks, efficacy was among others evaluated based on Ocular Surface Disease Index (OSDI), ocular surface symptoms intensity, general clinical impression, tear break-up time (TBUT), corneal fluorescein staining using the Oxford grading scale, tear volume, and matrix metalloproteinase-9 (MMP-9) concentration in the tear film. Safety evaluation included visual acuity, intraocular pressure, and the incidence of adverse events. Co-primary endpoints were the mean percent changes from baseline of TBUT and OSDI after four weeks. Results: In total 80 patients were included, of whom 37 in the PUFA group and 39 in the povidone group were evaluable for the co-primary endpoints. Patients had a mean age of 52 years and >80% were women. Both co-primary endpoints (TBUT and OSDI) significantly improved from baseline in both treatment groups, at Week 4 and Week 12 and the statistical analysis demonstrated topical omega-3 PUFA to be non-inferior to 2% povidone for these two parameters. Both treatments resulted in a significant improvement of most secondary efficacy endpoints as well, often with a slight difference in favor of PUFA, not reaching statistical significance though. One non-severe, treatment-related local AE was reported in each group. Conclusion: Omega-3 PUFA-based eye drops proved to be non-inferior to povidone-containing eye drops in the treatment of signs and symptoms of dry eye. This treatment may thus be an additional tool for the management of DED.

Corneal limbal microenvironment can induce transdifferentiation of hair follicle stem cells into corneal epithelial-like cells.

The aim of this study was to investigate the transdifferentiation potential of murine vibrissa hair follicle (HF) stem cells into corneal epithelial-like cells through modulation by corneal- or limbus-specific microenvironmental factors. Adult epithelial stem cells were isolated from the HF bulge region by mechanical dissection or fluorescence-activated cell sorting using antibodies to alpha6 integrin, enriched by clonal expansion, and subcultivated on various extracellular matrices (type IV collagen, laminin-1, laminin-5, fibronectin) and in different conditioned media derived from central and peripheral corneal fibroblasts, limbal stromal fibroblasts, and 3T3 fibroblasts. Cellular phenotype and differentiation were evaluated by light and electron microscopy, real-time reverse transcription-polymerase chain reaction, immunocytochemistry, and Western blotting, using antibodies against putative stem cell markers (K15, alpha6 integrin) and differentiation markers characteristic for corneal epithelium (K12, Pax6) or epidermis (K10). Using laminin-5, a major component of the corneo-limbal basement membrane zone, and conditioned medium from limbal stromal fibroblasts, clonally enriched HF stem and progenitor cells adhered rapidly and formed regularly arranged stratified cell sheets. Conditioned medium derived from limbal fibroblasts markedly upregulated expression of cornea-specific K12 and Pax6 on the mRNA and protein level, whereas expression of the epidermal keratinocyte marker K10 was strongly downregulated. These findings suggest that adult HF epithelial stem cells are capable of differentiating into corneal epithelial-like cells in vitro when exposed to a limbus-specific microenvironment. Therefore, the HF may be an easily accessible alternative therapeutic source of autologous adult stem cells for replacement of the corneal epithelium and restoration of visual function in patients with ocular surface disorders.

SFTA3 - a novel surfactant protein of the ocular surface and its role in corneal wound healing and tear film surface tension.

The study aimed to characterize the expression and function of SFTA3 at the ocular surface and in tears. Ocular tissues, conjunctival (HCjE) and human corneal (HCE) epithelial cell lines as well as tearfilm of patients suffering from different forms of dry eye disease (DED) were analyzed by means of RT-PCR, western blot, immunohistochemistry, and ELISA. A possible role of recombinant SFTA3 in corneal wound healing was investigated performing in vitro scratch assays. Tear film regulatory properties were analyzed with the spinning drop method and the regulation of SFTA3 transcripts was studied in HCE and HCjE after incubation with proinflammatory cytokines as well as typical ocular pathogens by real-time RT-PCR and ELISA. The results reveal that human ocular tissue as well as tears of healthy volunteers express SFTA3 whereas tears from patients with DED showed significantly increased SFTA3 levels. In vitro wounding of HCE cell cultures that had been treated with recombinant SFTA3 demonstrated a significantly increased wound closure rate and rSFTA3 reduced the surface tension of tear fluid. The results indicate that SFTA3 at the ocular surface seemed to be involved in wound healing and the reduction of surface tension.

Hepatitis C and ocular surface disease.

PURPOSE: To assess the frequency of changes in the ocular surface and the presence of hepatitis C virus (HCV) in tear samples of patients with chronic HCV infection. DESIGN: Prospective, nonrandomized, clinical, interdisciplinary, single-center study. METHODS: Seventy-one patients with previously untreated chronic HCV infection and a control group consisting of 66 patients without systemic HCV infection were enrolled in the trial. The patients with HCV infection were screened for ocular symptoms, visual acuity, and ocular changes. Tear production was measured by the Jones test. Conjunctival impression cytologic analysis was performed. The presence of HCV ribonucleic acid (RNA) in tear and blood samples was determined by quantitative polymerase chain reaction. RESULTS: On examination, systemic HCV infection was present for a median of 30 months. Fifty percent of all HCV patients showed a decrease in tear production measured by the Jones test. Apart from epithelial changes related to dry eye syndrome in 12 patients, two patients presented mild peripheral corneal thinning. Polymerase chain reaction analysis detected HCV RNA in five (10%) of 52 tear samples. HCV RNA levels in tear samples (mean, 1.0 x 10(4) copies/ml) were considerably lower than in blood samples (mean, 5.3 x 10(5) copies/ml). CONCLUSIONS: Dry eye syndrome is the most frequently observed ocular feature in HCV infection. Patients with HCV infection (age range, 21 to 60 years) compared with the controls had a significant lower tear production (P = .05). The presence of HCV RNA in 10% of tear samples emphasizes the potential risk of viral transmission through tears.

Diagnosis of X-Linked Hypohidrotic Ectodermal Dysplasia by Meibography and Infrared Thermography of the Eye.

PURPOSE: X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of ectodermal dysplasia. Clinical characteristics include meibomian gland disorder and the resulting hyperevaporative dry eye. In this study, we evaluated meibography and ocular infrared thermography as novel methods to diagnose XLHED. METHODS: Eight infants, 12 boys and 14 male adults with XLHED and 12 healthy control subjects were subjected to a panel of tests including the ocular surface disease index (OSDI), meibography and infrared thermography, non-invasive measurement of tear film break-up time (NIBUT) and osmolarity, Schirmer's test, lissamine green staining and fluorescein staining. Sensitivity and specificity were determined for single tests and selected test combinations. RESULTS: Meibography had 100% sensitivity and specificity for identifying XLHED. Infrared thermography, a completely non-invasive procedure, revealed a typical pattern for male subjects with XLHED. It was, however, less sensitive (86% for adults and 67% for children) than meibography or a combination of established routine tests. In adults, OSDI and NIBUT were the best single routine tests (sensitivity of 86% and 71%, respectively), whereas increased tear osmolarity appeared as a rather unspecific ophthalmic symptom. In children, NIBUT was the most convincing routine test (sensitivity of 91%). CONCLUSIONS: Meibography is the most reliable ophthalmic examination to establish a clinical diagnosis in individuals with suspected hypohidrotic ectodermal dysplasia, even before genetic test results are available. Tear film tests and ocular surface staining are less sensitive in children, but very helpful for estimating the severity of ocular surface disease in individuals with known XLHED.

Palate Lung Nasal Clone (PLUNC), a Novel Protein of the Tear Film: Three-Dimensional Structure, Immune Activation, and Involvement in Dry Eye Disease (DED).

PURPOSE: Palate Lung Nasal Clone (PLUNC) is a hydrophobic protein belonging to the family of surfactant proteins that is involved in fluid balance regulation of the lung. Moreover, it is known to directly act against gram-negative bacteria. The purpose of this study was to investigate the possible expression and antimicrobial role of PLUNC at the healthy ocular surface and in tears of patients suffering from dry eye disease (DED). METHODS: Bioinformatics and biochemical and immunologic methods were combined to elucidate the structure and function of PLUNC at the ocular surface. Tissue-specific localization was performed by using immunohistochemistry. The PLUNC levels in tear samples from non-Sjögren's DED patients with moderate dry eye suffering either from hyperevaporation or tear deficiency were analyzed by ELISA and compared with tears from healthy volunteers. RESULTS: Palate Lung Nasal Clone is expressed under healthy conditions at the ocular surface and secreted into the tear film. Protein modeling studies and molecular dynamics simulations performed indicated surface activity of PLUNC. In vitro experiments revealed that proinflammatory cytokines and bacterial supernatants have only a slight effect on the expression of PLUNC in HCE and HCjE cell lines. In tears from DED patients, the PLUNC concentration is significantly increased (7-fold in evaporative dry eye tears and 17-fold in tears from patients with tear deficiency) compared with healthy subjects. CONCLUSIONS: The results show that PLUNC is a protein of the tear film and suggest that it plays a role in fluid balance and surface tension regulation at the ocular surface.

Prospective, randomized, controlled comparison of SYSTANE UD eye drops versus VISINE INTENSIV 1% EDO eye drops for the treatment of moderate dry eye.

PURPOSE: The aim of this prospective, randomized, clinical, single-center study was to compare the safety and efficacy of 2 ocular surface lubricant eye drops: preservative-free hydroxypropyl (HP)-Guar (SYSTANE UD(®)) eye drops versus preservative-free Tamarindus indica seed polysaccharide (TSP) 1% (VISINE INTENSIV 1% EDO(®)) eye drops. METHODS: Fifty-six eyes of 28 patients with moderate keratoconjunctivitis sicca (DEWS severity level 2) were enrolled in the trial. Patients were randomized for 2 treatment groups (SYSTANE UD eye drops vs. VISINE INTENSIV 1% EDO eye drops). The eye drops in both groups were applied 5 times per day for 3 months. Statistical analyses were performed using Statistica™ software (Mann-Whitney U-test and Wilcoxon test). P-Values<0.05 were considered significant. RESULTS: After 3 months of treatment the patients of both groups had subjective benefit in the relief of symptoms of dry eye disease evaluated by the Ocular Surface Disease Index (OSDI) questionnaire score. Patients treated with HP-Guar and TSP showed improvements in tear film stability measured by tear break-up time (TBUT), which are statistically significant in the HP-Guar group (P=0.02). CONCLUSIONS: The results of this clinical trial show improvements of symptoms and signs in patients with moderate dry eye after the consistent use of preservative-free HP-Guar and TSP lubricant eye drops. Both artificial tear formulations produce amelioration in tear film stability improving eye conditions and patient quality of life. HP-Guar seems to be slightly more effective in improving ocular surface protection by decreasing tear film evaporation.

Tear film osmolarity measurements in dry eye disease using electrical impedance technology.

PURPOSE: Tear film hyperosmolarity is recognized as an important pathogenetic factor in dry eye syndrome, but difficulties in its measurement have limited its utility in the recent past. This prospective, nonrandomized, clinical single-center study investigates the osmolarity in tear samples of patients with keratoconjunctivitis sicca compared with healthy controls. METHODS: One hundred thirty-three patients [aged 58 years (51-64 years), 86 women and 47 men] with moderate to severe keratoconjunctivitis sicca and 95 controls [aged 52 years (48-61 years), 55 women and 40 men] were enrolled in the trial. Tear samples were collected directly from the inferior lateral tear meniscus. Inclusion criteria were a tear breakup time of less than 5 seconds, a Schirmer test with anesthesia less than 5 mm, and positive symptoms (Ocular Surface Disease Index score > 83). Tear film osmolarity was analyzed by the TearLab osmometer. RESULTS: In our study, patients with moderate to severe keratoconjunctivitis sicca showed a tear film osmolarity of 320 mOsmol/L (301-324 mOsmol/L). The results of the control group were 301 mOsmol/L (298-304 mOsmol/L). Our results revealed a significantly higher tear film osmolarity in patients with moderate to severe keratoconjunctivitis sicca compared with the control group. The sensitivity was 87%, and the specificity was 81%. CONCLUSIONS: Our results approved the referent value in moderate to severe dry eye of approximately 316 mOsmol/L, as described in the literature. The results showed a significantly higher tear film osmolarity in patients with severe keratoconjunctivitis sicca compared with the healthy controls. Testing tear film osmolarity can be a very effective objective diagnostic tool in the diagnosis of dry eye disease.

Evidence of endothelial cell migration after descemet membrane endothelial keratoplasty.

PURPOSE: To investigate the hypothesis that adult corneal endothelial cells can migrate after Descemet membrane endothelial keratoplasty (DMEK). DESIGN: Prospective observational study. METHODS: Five patients with Fuchs endothelial dystrophy were examined 1 year after uneventful DMEK. These patients had been selected on the basis of slightly decentered grafts and/or large descemetorrhexis showing areas of denuded corneal stroma, which were covered by neither the patients' Descemet membrane (DM) nor the graft. These areas were investigated by in vivo confocal laser scanning microscopy using a specially designed Heidelberg Retina Tomograph II and Rostock cornea module equipped with custom-made software. Source data (frame rate 30 Hz, 384 × 384 pixels, 400 × 400 µm) were used to create large-scale maps of the scanned area in automatic real-time composite mode. In each case an on-line mapping with maximum size up to 3.2 × 3.2 mm (3072 × 3072 pixels) was performed. RESULTS: Corneal stroma overlying areas devoid of DM was transparent. In vivo confocal laser scanning microscopy of stroma devoid of DM revealed a monolayer of endothelial cells in all patients observed. The morphologic pattern of these cells was similar to that of endothelial cells on DM grafts but different from the morphology of the patients' own endothelium, suggesting migration of donor endothelial cells from DMEK grafts. CONCLUSIONS: The results strongly support the hypothesis that adult corneal endothelial cells are able to migrate in the human eye. Furthermore, we provide evidence to support the hypothesis that grafted endothelium migrates onto the host tissue, repopulating the corneal stroma with a regular endothelial phenotype.

Long-term refractive and visual outcome after penetrating keratoplasty only versus the triple procedure in Fuchs' dystrophy.

BACKGROUND: Long-term refractive and visual outcome after penetrating keratoplasty (PK) only and the triple procedure in eyes with Fuchs' endothelial dystrophy were assessed and compared. DESIGN: Retrospective, non-randomized, cross-sectional, clinical, single-centre study. METHODS: Ninety-two eyes of 87 patients were divided into two groups. Group 1 consisted of 28 eyes (mean age 62+/-13 years) that had undergone PK only and group 2 consisted of 64 eyes (mean age 69+/-10 years) that had undergone the triple procedure. Inclusion criteria were: (1) Fuchs' dystrophy, (2) central nonmechanical trephination, (3) double-running suturing technique and (4) availability of 'two-sutures-out' findings. In all eyes, a central trephination was performed (donor trephination from the epithelial side) using the 193-nm excimer laser along metal masks with eight 'orientation teeth/notches'. A double-running 10-0 nylon suture was applied in all eyes. Subjective refractometry (trial glasses), standard keratometry (Zeiss) and corneal topography analysis (TMS-1, Tomey) were performed in all eyes with 'two-sutures-in', 'one-suture-out', and 'two-sutures-out'. Main outcome measures included refractive cylinder, keratometric and topographic net astigmatism, keratometric and topographic central power, best-corrected visual acuity (BCVA), spherical equivalent (SE) of manifest refraction, surface regularity index (SRI), surface asymmetry index (SAI), and regularity of keratometry mires. RESULTS: The results were compared between the two groups (i.e. group 1 vs group 2) at various stages (i.e. 'two-sutures-in', 'one-suture-out', 'two-sutures-out'). Refractive cylinder in dioptres [D] was 2.5/2.0/2.5 vs 2.0/1.5/3.0, keratometric astigmatism [D] was 3.5/2.6/3.0 vs 3.5/3.1/3.5 and topographic astigmatism [D] was 3.9/4.1/4.9 vs 4.2/5.0/5.1. Keratometric central power [D] was 41.7/42.4/43.8 vs 41.5/41.9/43.3 and topographic central power [D] was 42.3/43.6/43.7 vs 42.6/41.8/44.3. BCVA was 0.5/0.6/0.6 vs 0.5/0.5/0.5. SE [D] was 0.0 /0.0/-0.5 vs -0.5/-0.5/-1.1. SRI was 1.5/1.1/1.0 vs 1.4/1.4/1.2 and SAI was 1.0/0.8/1.0 vs 1.3/1.2/1.0. The proportion of 'regular' and 'mildly irregular' keratometry mires was 44% / 69% / 68% vs 29% / 46% / 66%. The differences between the two groups did not reach statistical significance at any of the stages. CONCLUSIONS: Refractive and visual outcome after the triple procedure did not differ significantly from that after PK only. Therefore, we recommend the triple procedure in elderly patients with Fuchs' dystrophy and cataract to avoid delayed visual rehabilitation and a second surgical procedure.