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T Kaercher

Publications and source records attributed to T Kaercher.

11 recordsLinked to original sources
PubMed2004

Ocular symptoms and signs in patients with ectodermal dysplasia syndromes.

PURPOSE: The ectodermal dysplasia syndromes are underestimated although precise inclusion criteria have been formulated. The purpose is to establish easily detectable ophthalmologic symptoms and signs as reliable criteria for ectodermal dysplasia syndromes. METHODS: Thirty-six patients with confirmed ectodermal dysplasia syndromes were included in an observational case series: hypohidrotic ectodermal dysplasia (30), EEC syndrome (3), AEC syndrome (2), Gorlin-Goltz syndrome (1). Each patient was examined ophthalmologically. The principal outcome measures were ocular symptoms and signs in patients with different ectodermal dysplasia syndromes of varying severity. METHODS: Some 94.4% of the patients suffered from dry eye symptoms. Reduction of eyebrows was seen in 94.4%; the lashes were altered in 91.6%. Changes of the meibomian glands were detected in 95.45%. Corneal changes such as pannus occurred later in life. CONCLUSIONS: Alterations of the meibomian glands, which were detected by meibomianoscopy, are the most reliable ocular sign of ectodermal dysplasia syndromes.

Adolescent↗
PubMed2004

[Blepharitis].

Blepharitis is characterized by a great variety of clinical manifestations, which often include alterations of the ocular surface. This as well as its tendency to be therapy-resistant and recurrent explains why blepharitis marks a challenge for all ophthalmologists. Occasionally dermatologic diseases represent one of the causes of the disease, thus calling for an interdisciplinary approach. The present article describes the state of the art with regard to pathogenesis and therapy of blepharitis.

Anti-Bacterial Agents↗
PubMed1999

How the most common preservative affects the Meibomian lipid layer.

PURPOSE Effects of preservatives like benzalkonium chloride on the tear film are often hypothetized. With regard to the Meibomian lipid layer only few data are available. In order to receive precise information about the effect of benzalkonium chloride on the Meibomian lipid layer we performed in vitro experiments using a direct optical control of the films. METHODS Meibomian gland secretion was spread on a water subphase containing benzalkonium chloride in concentrations of 0.001%, 0.005%, 0.01%, 0.05%, and 0.1%, respectively. This aqueous subphase was chosen in analogy to the aqueous tear film layer. In our experimental assay, the pH was 5.5, the temperature was 20 degrees C. The spreading process and the quality of the films were controlled by the Brewster Angle Microscope. RESULTS Benzalkonium chloride was well tolerated up to concentrations of 0.005%. Concentrations > 0.005% affected the spreading process forming domains, and instable films. CONCLUSIONS. Thus it could be demonstrated that there is a critical concentration of benzalkonium chloride which destroys the spreading and alters the morphology of the Meibomian lipid layer. These results were confirmed by a modified method injecting benzalkonium chloride in the subphase after spreading the Meibomian lipid layer. Therefore eye drops with benzalkonium chloride in concentrations above 0.005% should be abandoned in clinical therapy.

Journal Article↗
PubMed1995

[Morphology of the Meibomian lipid film. Results of Brewster angle microscopy].

Meibomian lipid layers were studied in the anterior mirror area by reflecting microscopy and interference microscopy. Using these techniques, it was not possible to correlate the biophysical and morphological data. Brewster angle microscopy provides direct observation of the spread Meibomian lipid layer with 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, causing reflection of light. The Meibomian lipid layer was studied in a Langmuir-type trough. At 5.0 mN/m the lipid layers are homogeneous and mobile, consisting of areas of higher and lower reflectivity. In patients with meibomitis the films are inhomogeneous and immobile. The thickness of the areas of lower reflectivity is 2 nm, the high reflectivity lipids are 8-10 nm thick. According to these results, Meibomian gland secretion can form monolayers under in vitro conditions.

Blepharitis↗
PubMed1994

Biophysical behaviour of the infant Meibomian lipid layer.

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.

Biophysical Phenomena↗
PubMed1992

Biophysical characteristics of the Meibomian lipid layer under in vitro conditions.

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.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1989

[Stability and flexibility of the lipid layer of the tear film and their pathologic changes in a biophysical experiment].

In vitro experiments with meibomian gland secretion from healthy subjects, patients with keratoconjunctivitis sicca and meibomianitis were performed. In addition, patients of different age groups of both sexes were also tested. The biophysical experiments included continuous measurement of surface pressure and surface potential under compression and decompression conditions. Surface pressure was determined by a Wilhelmy type film balance; surface potential was determined using the vibrating plate method. In the age group up to 60 years, the surface potential of females, males and patients with keratoconjunctivitis sicca showed a characteristic peak of 200 mV under compression, which was fully reversible under decompression. Females, males and patients with keratoconjunctivitis sicca over 60 years of age showed changes in the surface potential under decompression which indicated that the secretion was unstable and inhomogeneons. Patients with meibomianitis presented characteristic changes of surface potential. Qualitative alteration of the secretion may be the corresponding interpretation. The above biophysical methods have been used for the first time under clinical aspects.

Eyelids↗
PubMedDate not supplied

Brewster angle microscopy. A new method of visualizing the spreading of Meibomian lipids.

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.

Humans↗