[Recanalisation by Probing with a Bicanalicular Silicone Tube (Oggel Silicone Intubation) in Patients with Acquired Lacrimal Stenosis]. / Rekanalisierung durch Sondierung mit Oggel-Sonden-Implantation bei erworbener Tränenwegsstenose.

OBJECTIVES: Recanalisation and bicanalicular splinting with silicone tube is one therapeutic option for acquired lacrimal duct stenosis, and restenosis is frequently achieved. The aim was to determine the therapeutic success of Oggel silicone intubation after lacrimal syringing and probing. We also analysed other characteristics of the complaint and compared the therapeutic success with published results. METHODS: Therapeutic success was defined as subjective absence of complaints. Other complaint features - directly after explantation of the Oggel tube, one month after explantation and one year after explantation - were retrospectively collected by a patient questionnaire, and a questionnaire for the attending ophthalmologist. These were completed with information from the patient's file. We included 82 procedures performed at the Dept. of Ophthalmology, University of Ulm, between 2006 and 2015. Statistical testing of the impact of risk factors on therapeutic success was performed, using logistic regression analysis and the Mann-Whitney U test. Subgroups were compared using Pearson-Chi-square and Fisher's exact tests and a Kaplan-Meier analysis was also performed. RESULTS: Therapeutic success could be documented in 80.8% of patients after explantation of the Oggel tube, in 61.6% of patients after one month and in 42.5% of patients at one year (n = 82). There were no significant differences between the subgroups of stenosis localisation, or the patients' age or sex. There was also no significant influence of the patient's age, the preoperative duration of complaints or risk factors predisposing for lacrimal duct stenosis. For the observation period of one year, the Kaplan-Meier analysis gave a probability of complaint-freeness of 52.2% for the patient group, as well as a mean duration of the complaint-free period of 34.2 weeks. CONCLUSION: The results allow a prognostic assessment of the therapeutic success in the absence of significant differences in the subgroups. The therapeutic success of bicanalicular silicone intubation with the Oggel tube was in the lower third of comparable studies. The results conform to the observation that there is a progressive decline of therapeutic success. The comparison of the literature turned out to be methodically more difficult due to differences in study characteristics. Standardisation would make sense for future studies.

Sitagliptin and the Blood-Retina Barrier: Effects on Retinal Endothelial Cells Manifested Only after Prolonged Exposure.

Inhibitors of dipeptidyl peptidase-4 (DPP-4) are widely used to treat diabetes mellitus, but data concerning their effects on the barrier stability of retinal endothelial cells (REC) in vivo and in vitro are inconsistent. Therefore, we studied whether the barrier properties of immortalized endothelial cells of the bovine retina (iBREC) were affected by the inhibitors of DPP-4 sitagliptin (10-1000 nM) and diprotin A (1-25 µM). Their effects were also investigated in the presence of VEGF-A165 because diabetic patients often develop macular edema caused by VEGF-A-induced permeability of REC. To detect even transient or subtle changes of paracellular and transcellular flow as well as adhesion of the cells to the extracellular matrix, we continuously monitored the cell index (CI) of confluent iBREC grown on gold electrodes. Initially, the CI remained stable but started to decline significantly and persistently at 40 h or 55 h after addition of sitagliptin or diprotin A, respectively. Both inhibitors did not modulate, prevent, or revert the persistent VEGF-A165-induced reduction of the CI. Interestingly, sitagliptin and diprotin A increased the expression of the tight-junction protein claudin-1 which is an important component of a functional barrier formed by iBREC. In contrast, expressions of CD29-a subunit of the fibronectin receptor-or of the tetraspanin CD9 were lower after extended treatment with the DPP-4 inhibitors; less of the CD9 was seen at the plasma membrane after prolonged exposure to sitagliptin. Because both associated proteins are important for adhesion of iBREC to the extracellular matrix, the observed low CI might be caused by weakened attachment of the cells. From our results, we conclude that extended inhibition of DPP-4 destabilizes the barrier formed by microvascular REC and that DPP-4 inhibitors like sitagliptin do not counteract or enhance a VEGF-A165-induced barrier dysfunction as frequently observed in DME.

[Depth Effect of Cold Atmospheric Pressure Plasma in Keratitis Therapy: A Corneal Stroma Tissue Model]. / Tiefenwirkung von kaltem Atmosphärendruckplasma in der Keratitistherapie: ein Hornhautstromagewebemodell.

The incidence of microbial keratitis has been increasing and is now 28 cases/100,000 inhabitants; this may be due to the more frequent use of contact lenses. Keratitis can lead to visual impairment and in severe cases with endophthalmitis to enucleation of the affected eye. As microorganisms are becoming more resistant to antibiotic therapy, there is a need for new therapeutic strategies. Cold atmospheric pressure plasma has already been successfully used to disinfect surfaces. This study investigates the efficacy of cold atmospheric pressure plasma against Escherichia coli in a depth-resolved corneal stroma tissue model.

[Augmented Reality in Ophthalmology: Technical Innovation Complements Education for Medical Students]. / Augmented Reality in der Augenheilkunde: Technische Innovation ergänzt studentische Lehre.

BACKGROUND: At the Medical Faculty of the University of Ulm, the learning objectives of ophthalmology are taught to students in a one-week block course in the fourth year of study. According to the National Competency-based Learning Objective Catalogue Medicine (NKLM), one of these learning objectives is the clinical examination of the eye, including the eye fundus examination. In order to best train this expertise as defined in the NKLM, a novel, augmented reality-based training simulator (Eyesi Indirect, VRmagic Holding AG, Mannheim, Germany) was integrated into the teaching at the University Eye Hospital Ulm. During the block week, two key questions were examined: Does the one week block lesson increase interest in ophthalmology? How do students assess the use of an innovative e-learning technology compared to three other classical teaching methods for learning ophthalmoscopy? MATERIAL/METHODS: As part of the student teaching (block weeks July and October 2016), 292 students were questioned by questionnaire anonymously and on a voluntary basis regarding their assessment of the block week and the training simulator at the beginning and end of the one week event. The ophthalmoscopies were classically practiced on the ophthalmoscope trainer, head model and on fellow students and then performed on the new training simulator. RESULTS: Overall, there was little interest among the students in ophthalmology. However, the block week helped to increase interest (p < 0.001). The assessments of attractiveness before and after the block week of ophthalmology as a later professional goal and as an optional subject in the practical year were also significantly increased (p < 0.001 or p = 0.031). With regard to the use of e-learning technologies, it was shown that the handling of the simulator for learning ophthalmoscopy was rated more attractive by the students than the classical technology-based teaching methods (all p < 0.01). The joy of learning could only be further increased by practicing on a fellow student (p = 0.051). CONCLUSION: The results of the present study show a positive impact of the block week on the attractiveness assessment of the specialty by the participating students. Innovative e-learning methods can increase the enjoyment of learning. However, the training simulator cannot provide a complete replacement of the training on a real person.

[In Vitro Study of Subablative Er : YAG Laser and Diode Laser Therapy vs. Thermal Cautery in Microbial Keratitis]. / In-vitro-Studie mit subablativem Er:YAG-Laser und Diodenlaser vs. Thermokauter zur Therapie der mikrobiellen Keratitis.

BACKGROUND: In microbial keratitis, thermal cautery leads to thermal necrosis associated with germ reduction. Subablative heating of the cornea using an Er : YAG laser or diode laser is an alternative option. Thermal effects and reproducibility of both procedures were investigated. MATERIAL AND METHODS: Thermal effects were monitored with an infrared imaging system. Temperature of stromal tissue of enucleated porcine eyes was measured. Effects of thermal injury were rated by microscopic photography and histopathologic examination. Reduction of living bacteria was visualized by laser scanning microscopy and fluorescent stain on stromal tissue models containing E. coli bacteria. RESULTS: Corneal samples showed thermal damage depths of 110 - 250 µm after thermal cautery at contact times of 1 - 3 s. Superficial temperature ranged from 70 to 80 °C. Thickness of thermal necrosis after laser irradiation was between 50 and 270 µm. Temperature ranged from 60 to 120 °C. Laser scanning microscopy of a stromal tissue model, comprising Escherichia coli bacteria in soft agar, showed a mortification of bacteria over 40% up to 100 µm depth after treatment for 25 s. Treatment with diode laser showed an even better effect: more than 60% of bacteria were dead up to 250 µm depth and more than 50% up to 450 µm depth in the stromal tissue model. CONCLUSIONS: All procedures are able to induce high temperatures in tissue to achieve effective germ reduction in corneal stroma. Effect and reproducibility of the thermal cautery procedure depends on the surgeon's experience. Energy dose and thermal effect can be calculated for the Er : YAG and diode laser procedure to affect the infected stromal layer selectively.

[Innovative Teaching Methods: Wet Lab-based Ophthalmosurgical Education for Medical Students]. / Innovative Lehrmethoden: Einsatz eines ophthalmochirurgischen Wetlabs im Studentenunterricht.

BACKGROUND: An increased demand for young physicians in Germany is causing increased competition to attract the best minds, even during their undergraduate studies. Therefore, it is the task of the university hospitals to offer their students the best possible courses in order to arouse interest in the relevant subject area. We therefore examined the impact of an ophthalmosurgical wet lab on teaching undergraduate medical students. MATERIAL/METHODS: Undergraduate medical students were offered voluntary participation in the ophthalmosurgical wet lab during an ophthalmology block week. At the beginning and at the end of the week, as well as at the end of the wet lab, the students answered questionnaires with questions about the interest in the field of ophthalmology and the specific assessment of the wet lab. RESULTS: The interest of the students in ophthalmology was increased by the block week and additionally by the wet lab. The wet lab enriched the block week and was rated as very good by the participants. The overall rating of the block week was significantly better among participants in the wet lab than in the group without wet lab participation. The wet lab gave the students great pleasure, enabled them to apply the acquired knowledge, gain valuable insights into ophthalmology, and was easily implemented. CONCLUSION: The integration of a wet lab into the block week was evaluated very positively by the students and gives them a valuable insight into the field of ophthalmology.

Adherence and viability of porcine lens epithelial cells on three different IOL materials in vitro.

BACKGROUND: The purpose of the study was to evaluate porcine lens epithelial cell (LEC) adhesion and viability on three different intraocular lens (IOL) materials. METHODS: The IOL materials tested were poly(methylmethacrylate) (PMMA), silicone and hydrophobic acrylate. Primary porcine LECs were cultured on four discs of each material over a period of 10 days and, additionally, on six discs of the hydrophobic acrylate over a period of 20 days. Cells grown on untreated wells of a 96-well microtiter plate served as a control. Cell adhesion was photodocumentated on days 1, 2, 3, 4, 6, 8, 10, 14,17 and 20. A cell viability test using the LIVE/DEAD kit (Molecular Probes) was carried out at the end of the investigation. Experiments were run in triplicate. Statistical analysis was performed using the Student's t-test. RESULTS: Confluent cell growth was reached on the hydrophobic acrylate discs and the control wells within 1 day and remained stable during the experiment. Only a few round cells were adherent on PMMA and silicone discs, and their number decreased during the experiment. After 10 days of culturing, the viability test (mean +/- SD) revealed 81.79 +/- 51.74% live cells on acrylate discs, which was not different from the control (105.83 +/- 21.78%, P=0.1589). Significantly lower relative numbers of live cells (P>0.0001) were found on PMMA (-0.62 +/- 2.24%) and silicone (21.47 +/- 8.42%) discs. The percentage of dead cells was significantly higher (P<0.0001) on hydrophobic acrylate discs (29.69 +/- 12.61%) compared to the control (-1.49 +/- 4.13%). After a culture period of 20 days, the percentage of live cells on hydrophobic acrylate discs (49.45 +/- 27.98%) was lower compared to day 10, but was not significantly different from control wells (58.77 +/- 10.71%) (P=0.2299). CONCLUSIONS: Significantly fewer cells grew on PMMA and silicone discs compared to the control. Confluent cell growth and numbers of viable cells comparable to the control were observed on hydrophobic acrylate discs after a culture period of 20 days with a significantly higher percentage of dead cells.

[Optical coherence tomography versus ultrasound biomicroscopy of conjunctival and eyelid lesions]. / Optische Kohärenztomographie versus Ultraschallbiomikroskopie bei Bindehaut- und Lidtumoren.

BACKGROUND: The value of ultrasound biomicroscopy in the diagnosis of conjunctival and eyelid lesions is still unknown. METHOD: For the examination of conjunctival and eyelid lesions, we used an anterior segment OCT (4optics, Lübeck) and an ultrasound biomicroscope (Humphrey, Zeiss, Oberkochen) with high frequency transducer (30 MHz). Included in this study were all patients with conjunctival and eyelid lesions, which were consecutively operated on between December 2002 and January 2003. Histological examination of the excised tissue was performed. RESULTS: 38 tumours of 35 patients, aged 8 - 93 years, were examined. 13 tumours were conjunctival lesions and 25 tumours were eyelid lesions. Histological examination displayed the presence of a pterygium (8/38), a seborrhoic keratosis (7/38), a cyst of the eyelid (5/38), a basal cell carcinoma of the eyelid (4/38), a compound naevus of the conjunctiva (4/38), a chalazion (3/38), a primary acquired melanosis (1/38), an actinic keratosis (1/38), a naevus (1/38), a cavernous haemangioma (1/38), a melanoma in situ (1/38), a foreign body (1/38), and an epidermoid cyst (1/38). Using both ultrasound biomicroscopy and optical coherence tomography (OCT) we were able to demonstrate a cystic tumour in the five patients (13 %) with a cyst of the eyelid. With OCT and with ultrasoundbiomicroscopy in all patients with pterygium a slit was found and in patients with compound naevus very small cystic structures were seen, but with OCT the imaging was more reliable. In patients with solid tumours the definite diagnosis could not be differentiated by ultrasound biomicroscopy or OCT alone. Using OCT, assessment of the margins of the tumours (particularly in depth) was impossible or uncertain. CONCLUSION: Compared to ultrasound biomicroscopy OCT is able to show very small cystic structures more distinctly. For assessing the margins of the tumour ultrasound biomicroscopy is the better tool.

[The role of protein kinase C in the pathophysiology of diabetic retinopathy]. / Die Bedeutung der Proteinkinase C in der Pathophysiologie der diabetischen Retinopathie.

Hyperglycemic control in diabetes mellitus is a major key to prevent the development and progression of diabetic retinopathy. One important pathomechanism in the development of diabetic complications is the activation of protein kinase C (PKC) induced by high glucose due to an increased diacylglycerol (DAG) level. Resulting vascular dysfunctions are increased vascular permeability and contractility, increased production of extracellular matrix and cell proliferation. The PKC isoenzyme family plays a fundamental role in the cellular signal transduction via phosphorylation and modification of enzymes, receptors, transcription factors and kinases. The PKC activation influences the gene transcription and ion transport. Different PKC isoenzymes function as mediators but also as inhibitors of the insulin effects. The hyperglycemia induced DAG production seems to predominantly activate PKC-beta in retinal vascular endothelial cells. The development of selective PKC-beta inhibitors enables new pharmacological therapeutical approaches for treatment of diabetic retinopathy. Ongoing clinical studies investigate if the treatment with specific PKC-beta inhibitors can prevent the progression of diabetic retinopathy and diabetic macular edema.

[Ultrasound biomicroscopy in eyelid lesions - a clinical study on 30 patients]. / Ultraschallbiomikroskopie bei Lidtumoren - eine klinische Studie an 30 Patienten.

BACKGROUND: The value of ultrasound biomicroscopy in the diagnosis of eyelid lesions is not well known. METHODS: For the examination of eyelid lesions, we used an ultrasound biomicroscope (Humphrey, Zeiss, Oberkochen) with high-frequency transducers (30 and 50 MHz). Between November 1998 and December 1999, 30 patients with eyelid lesions, range 8 to 86 years, were available for this study. RESULTS: Histological examination of the excised tissue displayed the presence of chalazion (9/30), basal cell carcinoma (7/30), seborrhoic keratosis (4/30), a granulomatous process (4/30), cysts (2/30), an epidermoid cyst (1/30), a nevus (1/30), a pilomatrixoma (1/30), and a comedo (1/30). With ultrasound biomicroscopy we were able to demonstrate a cyst or a cystic tumour in six patients (20 %); i. e. two patients with a cyst of the eyelid, two patients with chalazion, one patient with a granulomatous process and one patient with an epidermoid cyst. In the patients with solid tumours of the eyelid, final diagnosis with ultrasound biomicroscopy only is not possible. CONCLUSION: For evaluation of cystic or solid eyelid lesions, ultrasound biomicroscopy may be an additional diagnostic tool, e. g. for assessment of the margins of the tumour. However, up to now it is not possible to differentiate tumours if only ultrasound biomicroscopic findings are available.