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Thomas Kaercher,1 Elisabeth M Messmer,2,3 Thomas Berninger,4 Klaudia K Huber-van der Velden,5 Raphaela Geiger,6 Pauline Cipriano-Bonvin,7 Christina Jacobi8,9 1Augenarztpraxis, Heidelberg, Germany; 2Department of Ophthalmology, Ludwig-Maximilian-University, Munich, Germany; 3Praxis Professor Kampik & Kollegen, Munich, Germany; 4Augenzentrum, Olching, Germany; 5Augenheilkunde Lindenthal, Köln-Lindenthal, Germany; 6TRB Chemedica AG, Feldkirchen, Germany; 7TRB Chemedica International SA, Geneva, Switzerland; 8Augen & Haut Zentrum-Praxis Dr. Jacobi, Nuremberg, Germany; 9Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, GermanyCorrespondence: Thomas Kaercher, Augenarztpraxis, 48 Dossenheimer Landstr, Heidelberg, 69121, Germany, Tel +49 6221 400 888, Fax +49 6221 412 203, Email thomas.kaercher@meibomius.dePurpose: 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.Keywords: polyunsaturated fatty acids, povidone, dry eye disease, artificial tears, omega-3 fatty acid

CLINICAL RELEVANCE: Contrast thresholds under photopic and mesopic luminance conditions are compromised in subjects with vitreous degeneration. A plausible explanation is needed for the visual discomfort expressed by patients suffering from symptomatic vitreous degeneration. \ud \ud BACKGROUND: The current study investigates the effect of symptomatic vitreous degeneration on photopic and mesopic contrast at high spatial frequencies. \ud \ud METHODS: An age-matched sample of 115 subjects, comprising 30 subjects with symptomatic vitreous floaters (cases) and 85 healthy subjects (controls), was included in this study. Visual acuity and flicker thresholds were measured for all participants. Photopic and mesopic functional contrast thresholds at 10 cycles per degree were measured for all participants to assess the effect of floaters on contrast. Further, to determine the effect of posterior vitreous detachment on contrast, the sample was divided into three groups: cases with posterior vitreous detachment (n = 12); cases without posterior vitreous detachment (n = 18); and controls (n = 85), and their contrast thresholds were compared. \ud \ud RESULTS: Photopic and mesopic contrast thresholds were lower by 37.4% and 27.5%, respectively, when the cases were compared with the controls (p = 0.028 and p

Purpose To investigate the impact of supplementation with a targeted micronutrient formulation on the visual discomfort associated with vitreous degeneration. Methods In this clinical trial, 61 patients with symptomatic vitreous floaters were randomized to consume daily, the active supplement consisting of 125 mg L-lysine, 40 mg vitamin C, 26.3 mg Vitis vinifera extract, 5 mg zinc, and 100 mg Citrus aurantium or placebo for 6 months. Change in visual discomfort from floaters, assessed with the Floater Disturbance Questionnaire, was the primary outcome measure. Secondary outcome measures included best-corrected visual acuity, letter contrast sensitivity, photopic functional contrast sensitivity with positive and negative contrast polarity, and quantitative vitreous opacity areas. Results After supplementation, the active group reported a significant decrease in their visual discomfort from floaters (P < 0.001), whereas the placebo group had no significant change in their visual discomfort (P = 0.416). At 6 months, there was a significant decrease in vitreous opacity areas in the active group (P < 0.001) and an insignificant increase in vitreous opacity areas in the placebo group (P = 0.081). Also, there was a significant improvement in photopic functional contrast sensitivity with positive contrast polarity in the active group after supplementation (P = 0.047). Conclusions The findings of this study indicate improvements in vision-related quality of life and visual function of patients suffering from vitreous floaters after supplementation with a formulation of antioxidative and antiglycation micronutrients. Notably, these improvements were confirmed by the decrease in vitreous opacity areas in the active group. Translational Relevance This targeted dietary intervention should be considered to support patients with symptomatic vitreous degeneration.

Purpose: Meibomian gland disease is generally accepted as the leading cause for evaporative dry eye disease (DED). In a previous study, perfluorohexyloctane, a semifluorinated alkane, has been demonstrated to significantly increase tear film breakup time and to reduce corneal fluorescein staining in patients with evaporative DED, thereby vastly reducing dry eye-related symptoms. This study was set up to evaluate perfluorohexyloctane in a larger population of patients with Meibomian gland dysfunction. Methods: Seventy-two patients with Meibomian gland disease and associated dry eye received 1 drop of perfluorohexyloctane 4 times daily during an observational, prospective, multicenter, 6–8-week study. Clinical assessment included best-corrected visual acuity, intraocular pressure, Schirmer test I, tear film breakup time, anterior and posterior blepharitis assessment, number of expressible Meibomian glands, meibum quality and quantity, ocular surface fluorescein staining, lid margin and symptom assessment, and Ocular Surface Disease Index (OSDI©). Results: From the 72 patients recruited, 61 completed the trial per protocol. Nine patients did not apply the medication as recommended and 2 patients were lost to follow-up. Tear film breakup time, corneal and conjunctival fluorescein staining, number of expressible Meibomian glands, and severity of anterior and posterior blepharitis significantly improved after 6–8 weeks of perfluorohexyloctane application. In addition, symptoms improved as demonstrated by a significant decrease of OSDI-values from 37 (±13) to 26 (±16). Conclusions: In concordance with previous findings, 6–8 weeks of topical application of perfluorohexyloctane significantly improves clinical signs of Meibomian gland disease and associated mild to moderate DED.

Purpose: Evaporation of the tear film is heavily discussed as one core reason for dry eye disease (DED). Subsequently, new artificial tear products are developed that specifically target this pathomechanism. Perfluorohexyloctane (F6H8, NovaTears®) from the family of semifluorinated alkanes is a novel substance that has been approved as a medical device, as a nonblurring wetting agent for the ocular surface. Methods: Thirty patients with hyperevaporative dry eye received F6H8 during a prospective, multicenter, observational 6-week study. Patients were advised to apply 1 drop 4 times daily in both eyes. Parameters assessed included best corrected visual acuity, intraocular pressure, Schirmer I test, tear fluid, tear film breakup time (TFBUT), corneal staining, meibum secretion, and Ocular Surface Disease Index (OSDI©). Results: From the 30 patients recruited, 25 completed the trial per protocol. Four patients discontinued F6H8 and 1 patient did not present for follow-up. F6H8 treatment led to significant reduction of corneal staining and significant increase of Schirmer I and TFBUT. In addition, OSDI score dropped significantly from a mean of 55 (±23.0) to 34 (±22.4). Visual acuity and ocular pressure did not change. Conclusions: This prospective observational study shows significant beneficial effects in patients suffering from evaporative DED, using F6H8 in all the relevant parameters tested. The decrease of the OSDI by a mean of 21 points was particularly remarkable and clearly exceeds minimal, clinical important differences for mild or moderate and severe disease. Overall, F6H8 (NovaTears) seems to be safe and effective in treating mild to moderate hyperevaporative DED.

José Manuel Benitez del Castillo,1 Thomas Kaercher,2 Khaled Mansour,3 Edward Wylegala,4 Harminder Dua5 1Universidad Complutense, Madrid, Spain; 2Augenarztpraxis, Heidelberg, Germany; 3Department of Ophthalmology, Tjongerschans Hospital, Heerenveen, the Netherlands; 4Department of Ophthalmology, Medical University of Silesia, District Railway Hospital, Katowice, Poland; 5Division of Ophthalmology and Visual Sciences, Eye ENT Centre, Queens Medical Centre, Nottingham, UKAbstract: Meibomian gland dysfunction (MGD) is widespread and has significant impact on patients’ quality of life. Eyelid hygiene is the mainstay of treatment but is unstandardized and requires commitment from the patient and encouragement from the ophthalmologist. Blephasteam® is an eyelid warming device designed to be an easy-to-use and standardized treatment for MGD. In the present study, 73 patients were treated for 21 days with twice daily Blephasteam® sessions. The primary efficacy variable, a symptomatology visual analog scale score, declined from 63.07±21.23 (mean ± standard deviation) on day 0 to 41.90±25.49 on day 21. There were also improvements in a number of secondary efficacy variables including subjective ocular symptoms and clinical signs and symptoms of MGD and dry eye, though tear film breakup time and tear osmolarity were not improved. Global efficacy was assessed as satisfactory or very satisfactory in 83.8% of cases. Patient-reported subjective ocular symptoms declined during the study, and a majority of patients rated the efficacy of Blephasteam® as satisfactory or very satisfactory. Most patients found the device comfortable and were able to continue with normal activities (reading, watching TV, using a computer) during the Blephasteam® session. No safety or tolerability issues were identified.Keywords: dry eye, Blephasteam&reg

X-linked hypohidrotic ectodermal dysplasia (XLHED; ectodysplasin deficiency) has been classically described as affecting hair, sweat glands, and dentition. What may be underappreciated is the effect ectodysplasin deficiency has on glands surrounding the airways and eyes and the resulting chronic health issues. In this study, 12 male children (age range 6–13 years) and 14 male adults with XLHED (18–58 years of age) were investigated by pulmonary function tests, measurement of fractional exhaled nitric oxide, and by ophthalmologic assessments. Twelve healthy individuals (six children, six adults) served as controls. Signs of airway constriction and inflammation were detected in eight children with XLHED, including the youngest subject, and in ten adult XLHED patients. Increased tear osmolarity, reduced tear film break-up time, and other ocular abnormalities were also present at an early age. Five of 12 XLHED subjects not reporting a history of asthma and 7 of the 12 patients not reporting a history of dry eye issues showed at least two abnormal test results in the respective organ system. The presence of residual sweat ducts, suggestive of partial ectodysplasin gene expression, correlated with milder disease in two XLHED subjects with mutations affecting the collagen-like domain of ectodysplasin. Conclusion: The high prevalence of asthma-like symptoms in XLHED patients as young as 6 years and a similar prevalence of dry eye problems indicate that screening evaluation, regular monitoring, and consideration of therapeutic intervention should begin in early childhood.

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.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.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%).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.

Objective To determine the efficacy and safety of azithromycin 1.5% eye drops in a paediatric population with purulent bacterial conjunctivitis. Patients and methods This was a multicentre, international, randomised, investigator-masked study in 286 children with purulent discharge and bulbar conjunctival injection. Patients received either azithromycin 1.5% eye drops (twice daily for 3 days) or tobramycin 0.3% eye drops (every 2 h for 2 days, then four times daily for 5 days). Clinical signs were evaluated on day (D) 0, 3 and 7, and cultures on D0 and D7. The primary variable was the clinical cure (absence of bulbar conjunctival injection and discharge) on D3 in the worse eye for patients with positive cultures on D0. Results 286 patients (mean age 3.2 years; range 1d ay–17 years) were included; 203 had positive cultures on D0. Azithromycin was superior to tobramycin in clinical cure rate on D3 (47.1% vs 28.7%, p=0.013) and was non-inferior to tobramycin on D7 (89.2% vs 78.2%, respectively). Azithromycin treatment eradicated causative pathogens, including resistant species, with a similar resolution rate to tobramycin (89.8% vs 87.2%, respectively). These results were confirmed in a subgroup of patients younger than 24 months old. Conclusions Azithromycin 1.5% eye drops provided a more rapid clinical cure than tobramycin 0.3% eye drops in the treatment of purulent bacterial conjunctivitis in children, with a more convenient twice-a-day dosing regimen.

Brewster Angle Microscopy (BAM) provides a direct observation of the spread Meibomian lipid layer under simultaneous registration of the surface pressure. It is based on the fact that He-Ne-laser light, which is incident at a water-surface under the Brewster angle, does not reflect visible light. After spreading of a lipid film, the angle of the incident light beam varies thus causing reflection of light.The morphology of the Meibomian lipid layers was studied under continuous compression of the film. At 0.5 mN/m the film showed a loose, lagoonlike pattern. Compression up to 12.0 mN/m led to an immobile, soup-like, densely packed film.Patients with meibomias presented a simultaneous appearance of lagoonlike and densely packed parts of the film.Differences in reflectivity at different areas of the film can be used for thickness measurements. Meibomian lipid layers, under the authors' in vitro conditions, proved not to be thicker than 100 A. These results coincide with their results for Meibomian lipid laye...

Infants have been known occasionally to stare without blinking for almost a minute. This puts great demands on the stability of their tear-film. To verify the stability of infant tears, we performed biophysical experiments on Meibomian gland secretion, which forms the outermost layer of the tear-film. The secretion was taken from infants belonging to one of three age-groups (1.5 years, 4-5 years, 7-10 years). Under in vitro conditions we determined the surface pressure and the surface potential of the film by spreading the secretion over a water surface and subsequently compressing and decompressing it. Sufficient amounts of Meibomian gland secretion were expressed in all age-groups. The surface pressure and the surface potential of the tears in infants corresponded to those in healthy adults. It was also found that the younger the patient was, the better was the consistency of the surface potential under repeated periods of compression and expansion. In comparison with the secretion of healthy adults, the infant Meibomian gland secretion showed better biophysical characteristics and a correspondingly higher stability in the tear-film.

The biophysical behaviour of the Meibomian gland secretion was tested under in vitro conditions. Thereby, simultaneous recording of surface pressure and surface potential was performed. The Meibomian lipid layer was compared with other surface-active components like polyvinylalcohol and polyvinylpyrrolidone. On the other hand, Eledoisin was tested as an example for a surface-inactive substance. An attempt was made to describe the biophysical interaction between a given artificial tear substitute and the Meibomian lipid layer. With respect to the surface potential Dipalmitoyl-phosphatidyl-choline was established as an analogue for Meibomian gland secretion. Fluorescence measurements in the presence of a cyanine dye (1 N,N'dioctadecyloxacarbocyanine) were used as a method to localize the site of the characteristic potential change. From the fluorescence spectra under compression we conclude that the molecular change takes place at the lipid-subphase interface of the Meibomian lipid layer.

Objective: To evaluate the efficacy and tolerability of Optive™, a new dry eye product containing sodium carboxymethylcellulose (0.5%) and glycerol (0.9%), in patients with keratoconjunctivitis sicca (KCS). Methods: This was a non-interventional and observational study including patients with dry eye who required a change of medication or were naïve to dry eye treatment (N = 5,277). Disease severity, tear break-up time (TBUT), tolerability, and change in clinical symptoms were recorded at baseline and at final visit (2 to 4 weeks after first treatment). Results: The severity of KCS was mild in 18.6%, moderate in 59.9%, and severe in 21.5% of patients based on physicians’ assessment. TBUT was measured in 4,338 patients before switching to or initiating therapy with Optive and at final visit. Baseline measurement of mean TBUT was 7.7 ± 3.9 seconds. This value increased to 10.0 ± 4.7 seconds at final visit. Most patients (85.4%) reported improvement in local comfort. The majority (75.1%) of patients felt an improvement in symptoms after changing their treatment. Two percent of patients reported adverse events, and 0.4% were treatment-related. Conclusions: Optive was well tolerated and improved the symptoms of dry eye after 2 to 4 weeks.

Thomas Kaercher1, Patricia Buchholz2, Friedemann Kimmich31Augenarztpraxis, Heidelberg, Germany; 2Allergan Europe, Ettlingen, Germany; 3Eyecons, Pfinztal, GermanyObjective: To evaluate the efficacy and tolerability of OptiveTM, a new dry eye product containing sodium carboxymethylcellulose (0.5%) and glycerol (0.9%), in patients with keratoconjunctivitis sicca (KCS).Methods: This was a non-interventional and observational study including patients with dry eye who required a change of medication or were naïve to dry eye treatment (N = 5,277). Disease severity, tear break-up time (TBUT), tolerability, and change in clinical symptoms were recorded at baseline and at final visit (2 to 4 weeks after first treatment).Results: The severity of KCS was mild in 18.6%, moderate in 59.9%, and severe in 21.5% of patients based on physicians’ assessment. TBUT was measured in 4,338 patients before switching to or initiating therapy with Optive and at final visit. Baseline measurement of mean TBUT was 7.7 ± 3.9 seconds. This value increased to 10.0 ± 4.7 seconds at final visit. Most patients (85.4%) reported improvement in local comfort. The majority (75.1%) of patients felt an improvement in symptoms after changing their treatment. Two percent of patients reported adverse events, and 0.4% were treatment-related.Conclusions: Optive was well tolerated and improved the symptoms of dry eye after 2 to 4 weeks.Keywords: keratoconjunctivitis sicca, dry eye, sodium carboxymethylcellulose, glycerol, OptiveTM

Dry eye, or keratoconjunctivitis sicca (KCS), is divided into two subgroups, tear-deficient and evaporative. Each form calls for a different therapeutic approach and it is therefore essential to apply a combination of diagnostic tests in order to establish the exact diagnosis.The diagnosis of KCS is based in part on the patient's history and symptoms and in part on the application of specific tests. Several non-invasive tests exist (e.g. slit-lamp examination, meniscometry, interferometry). Mildly invasive tests are the fluorescein tests, staining with lissamine green, meibometry and meibography. Markedly invasive tests include the Schirmer test and staining with rose bengal. Additional histological procedures are the ocular ferning test and impression cytology.A combination of diagnostic tests leads to one of the two forms of KCS. Its severity is calculated according to grading systems, which exist for several tests. The longitudinal observation of the dry eye patient is provided on the basis of this same grading system, although limited reproducibility is reported for some tests.The diagnostic steps for dry eye patients can be efficiently arranged. In most of the cases, non-invasive or mildly invasive tests provide an accurate diagnosis.

Background: Dry eye, or keratoconjunctivitis sicca (KCS), is divided into two subgroups, tear-deficient and evaporative. Each form calls for a different therapeutic approach and it is therefore esse

Although known for almost 80 years, the physiological role of plasmalogens (PLs), the major mammalian ether lipids (ELs), is still enigmatic. Humans that lack ELs suffer from rhizomelic chondrodysplasia punctata (RCDP), a peroxisomal disorder usually resulting in death in early childhood. In order to learn more about the functions of ELs, we generated a mouse model for RCDP by a targeted disruption of the dihydroxyacetone-phosphate acyltransferase gene. The mutant mice revealed multiple abnormalities, such as male infertility, defects In eye development, cataract and optic nerve hypoplasia, some of which were also observed in RCDP. Mass spectroscopic analysis demonstrated the presence of highly unsaturated fatty acids including docosahexaenoic acid (DHA) in brain PLs and the occurrence of PLs in lipid raft microdomains (LRMs) isolated from brain myelin. In mutants, PLs were completely absent and the concentration of brain DHA was reduced. The marker proteins flotillin-1 and F3/contactin were found in brain LRMs in reduced concentrations. In addition, the gap junctional protein connexin 43, known to be recruited to LRMs and essential for lens development and spermatogenesis, was down-regulated In embryonic fibroblasts of the EL-deficient mice. Free cholesterol, an important constituent of LRMs, was found in these fibroblasts to be accumulated in a perinuclear compartment. These data suggest that the EL-deficient mice allow the identification of new phenotypes not related so far to EL-deficiency (male sterility, defects in myelination and optic nerve hypoplasia) and indicate that PLs are required for the correct assembly and function of LRMs.

Thomas Kaercher,1 Ulrich Thelen,2 Gerrett Brief,3 Robert J Morgan-Warren,4 Richard Leaback41Augenarztpraxis, Heidelberg, Germany; 2University of Münster, Münster, Germany; 3Ruhr University, Bochum, Germany; 4Allergan Holdings Ltd, Marlow, UK Objective: The aim was to evaluate the efficacy of Optive Plus®, an artificial tear containing castor oil, in patients with dry eye, in a routine clinical setting. Methods: This was a prospective, noninterventional study of patients with dry eye who switched from a prior therapy or who were naïve to treatment (n=1,209). Patients were issued Optive Plus® artificial tears. Dry eye severity, tear break-up time (TBUT), Schirmer score, Ocular Surface Disease Index (OSDI) score, and patient assessment of symptoms were recorded at baseline and at the follow-up visit (4 weeks after starting Optive Plus®). Results: The cause of dry eye was determined to be aqueous deficiency, lipid deficiency, or a mixture of aqueous and lipid deficiency (in 19.5%, 20.1%, and 47.8%, respectively, of the total study population). The severity of dry eye decreased from baseline to the follow-up visit, showing a decrease of the more severe levels (2–4) and a concurrent increase in mild level (1) of the rating scale. Patients reported an improvement in dry eye symptoms over the duration of the study, specifically 74.2% (n=152), 85.4% (n=182), and 82.4% (n=417) of patients in the aqueous-deficient, lipid-deficient, and mixed-deficiency groups, respectively. TBUT was measured in 475 patients. Baseline measurements for mean and standard deviation were 9.0±3.5, 7.1±3.6, and 6.6±3.0 seconds for the aqueous-deficient, lipid-deficient, and mixed-deficiency groups, respectively. These increased to 10.5±3.5, 10.0±3.6, and 9.2±3.1 seconds at the final visit. Overall, 92.5% of all patients were satisfied with the use of Optive Plus®, and 86% said they would purchase Optive Plus®. Ten percent of patients reported adverse events, and 1.8% of all patients experienced treatment-related adverse events. Conclusion: Optive Plus® was well tolerated and effective in reducing the signs and symptoms of all types of dry eye but is recommended for lipid-deficient dry eye patients. Keywords: dry eye, lipid-deficient, aqueous-deficient, meibomian, hyperosmolarity, evaporativeA Letter to the Editor has been received and published for this article.

The spreading behaviour of the Meibomian lipids is important for the integrity of the whole tear film. This paper presents the application of Brewster Angle Microscopy (BAM) for the observation of the spreading process in vitro. Meibomian gland secretions were studied in a Langmuir trough. The secretion was characterized by an extremely rapid continuous spreading, suggesting that enough material would be available to recover the superficial lipid layer of the tears between the blinks of the eye. This new technique provides important information on how the normal tear film works and how tear substitutes might act.

X-linked hypohidrotic ectodermal dyplasia (XLHED) is the most common form of ectodermal dysplasia. It often presents with ocular symptoms, already in early childhood. Multiple ophthalmological tests are available, but in early childhood only tests of lower invasiveness can be applied. We have evaluated tear film tests and ocular surface staining as screening methods in pediatric patients with signs of ectodermal dysplasia. These tests may also be used in adults with confirmed XLHED to determine the severity of ocular surface disease. Twelve children and 14 adults with XLHED were subjected to a panel of tests including the ocular surface disease index (OSDI), non-invasive measurement of tear film break-up time (NIBUT), osmolarity, Schirmer test, lissamine green staining, fluorescein staining, meibography and infrared thermography. Sensitivity and specificity were determined for single tests and selected test combinations. For adults with XLHED, OSDI, NIBUT and osmolarity were the best single routine tests (sensitivity between 84.6% and 85.7%; specificity of 100%). Their combination increased the sensitivity to 92.8%. Meibography yielded optimal results (100% sensitivity and specificity). Infrared thermography revealed a typical pattern for XLHED. In children with XLHED, NIBUT or OSDI were the most convincing single tests (sensitivity of 90.9% and 83.3%, respectively; specificity of 100% each), combination of which increased the sensitivity to 100%. More invasive tests such as meibography and infrared thermography led to good results if they were tolerated. Tear film tests can help to establish an early diagnosis in individuals with suspected XLHED, even before genetic test results are available. Meibomian gland disorder and resulting hyperevaporative dry eye are typical features of XLHED. Once the diagnosis is made, tear film tests are an important instrument to establish an effective therapy of dry eye disease.