Ex Vivo Micro-CT in Ophthalmology: Preparation and Contrasting for Non-invasive 3D-Visualisation. / Ex-vivo-Mikro-CT in der Augenheilkunde: Probenbehandlung und -kontrastierung für die 3D-Darstellung.

X-ray-based micro-computed tomography (micro-CT) is a largely non-destructive imaging method for the visualisation and analysis of internal structures in the ex vivo eye and affords high resolution. In contrast to other high-resolution imaging methods, micro-CT enables spatial recording of larger and more complex tissue structures, such as the anterior chamber of the eye. Special contrasting methods help to enhance the absorption properties of soft tissue, that is otherwise only weakly radiopaque. Critical point drying (CPD), as primarily used in scanning electron microscopy, offers an additional tool for improving differential contrast properties in soft tissue. In the visualisation of intraosseous soft tissue, such as the efferent lacrimal ducts, sample treatment by decalcification with ethylenediaminetetraacetic acid and subsequent CPD provides good results for micro-CT. Micro-CT can be used for a wide range of questions in 1. basic research, 2. application-related studies in ophthalmology (e.g. evaluation of the preclinical application of microstents for glaucoma treatment or analysis of the positioning of intraocular lenses) but also 3. as a supplement to ophthalmological histopathology.

Effects of prenatal Doppler ultrasound on the retina of the chick embryo in ovo.

Currently, the effect of prenatal ultrasound on foetal development is intensively discussed and the guidelines for prenatal diagnostics have been changed. However, data supporting these concerns are scarce. Therefore, we used an established in ovo model of the chicken embryo to investigate cell proliferation and apoptosis within the retina. A total of 21 chicken eggs were fenestrated on Day 5 and allocated to either the control (n = 8) or exposition group (n = 13). The exposition group was treated with pulsed-wave Doppler ultrasound (PWD) for 10 min while controls remained without treatment. After subsequent incubation (6-48 h), the eggs were sacrificed, and chicken embryos were examined morphologically (HE-staining) and immunohistochemically. Counting of apoptotic and proliferating cells per retina was performed using antibodies specific for phospho-histone-H3 and active caspase-3 in combination with a biotin-labelled secondary antibody and peroxidase conjugated avidin-biotin complex for chromogenic detection. Due to a rather low number of specimens at each time point after ultrasound exposition, we neglected the effects of incubation time and focused on treatment effects. This approach revealed that the median number of proliferating cells is reduced after 10 min of exposure to PWD (569 vs. 766), while the number of apoptotic cells is fairly comparable between groups (5 vs. 6). Our data contribute to a better understanding of prenatal US on foetal development by suggesting that PWD could have an impact on the number of proliferating cells in the developing chicken retina and therefore justify further investigations.

Development of a Novel Valve-Controlled Drug-Elutable Microstent for Microinvasive Glaucoma Surgery: In Vitro and Preclinical In Vivo Studies.

Purpose: Microinvasive glaucoma surgery (MIGS) has become an important treatment approach for primary open-angle glaucoma, although the safe and long-term effective lowering of intraocular pressure with currently available implants for MIGS is not yet achieved to a satisfactory extent. The study focusses on the development and in vitro and in vivo testing of a novel microstent for MIGS. Methods: A silicone elastomer-based microstent was developed. Implants were manufactured using dip coating, fs-laser cutting, and spray coating. Within the current study no antifibrotic drug was loaded into the device. Sterilized microstents were analyzed in vitro regarding pressure-flow characteristics and biocompatibility. Six New Zealand white rabbits were implanted with a microstent draining the aqueous humor from the anterior chamber into the subconjunctival space. Drainage efficacy was evaluated using oculopressure tonometry as a transient glaucoma model. Noninvasive imaging was performed. Results: Microstents were manufactured successfully and characterized in vitro. Implantation in vivo was successful for four animals with additional device fixation. Without additional fixation, dislocation of microstents was found in two animals. Safe and effective intraocular pressure reduction was observed for the four eyes with correctly implanted microstent during the 6-month trial period. Conclusions: The described microstent represents an innovative treatment approach for MIGS. The incorporation of a selectively antifibrotic drug into the microstent drug-elutable coating will be addressed in future investigations. Translational Relevance: The current preclinical study successfully provided proof of concept for our microstent for MIGS which is suitable for safe and effective intraocular pressure reduction and offers promising perspectives for the clinical management of glaucoma.

The Antibiotic Kitasamycin-A Potential Agent for Specific Fibrosis Preventing Therapy after Fistulating Glaucoma Surgery?

One major complication after fistulating glaucoma surgeries are fibroblast-mediated scarring processes and their specific prevention is key in the development of novel pharmaceutical concepts. Within this study a possible antifibrotic potential of kitasamycin (KM) in a transforming growth factor (TGF)-ß1-mediated fibroblast model was evaluated in vitro. Primary ocular fibroblasts were isolated, cultivated and a dose-response test including determination of the half maximal effective concentration (EC50) for KM was conducted. Transformation of fibroblasts into myofibroblasts was induced by TGF-ß1and immunofluorescence (IF), and Western blot (WB) analyses were performed with fibroblasts and myofibroblasts. IF analyses were carried out using antibodies against α-smooth muscle actin (α-SMA) and fibronectin, and protein detection of intracellular and extracellular proteins was performed by WB. Using the dose-response test, the viability, cytotoxicity and EC50 of KM after 24 and 48 h were determined. Fibroblasts exposed to various KM concentrations showed no increase in α-SMA and extracellular matrix expression. In TGF-ß1-stimulated myofibroblasts, KM inhibited the expression of α-SMA and fibronectin in a concentration-dependent manner. These findings demonstrate that KM could impair the transformation of fibroblasts into myofibroblasts and the expression of proteins involved in fibrotic processes, representing a potential agent for specific fibrosis prevention in future therapeutic concepts.

Quantitative systems pharmacology of the eye: Tools and data for ocular QSP.

Good eyesight belongs to the most-valued attributes of health, and diseases of the eye are a significant healthcare burden. Case numbers are expected to further increase in the next decades due to an aging society. The development of drugs in ophthalmology, however, is difficult due to limited accessibility of the eye, in terms of drug administration and in terms of sampling of tissues for drug pharmacokinetics (PKs) and pharmacodynamics (PDs). Ocular quantitative systems pharmacology models provide the opportunity to describe the distribution of drugs in the eye as well as the resulting drug-response in specific segments of the eye. In particular, ocular physiologically-based PK (PBPK) models are necessary to describe drug concentration levels in different regions of the eye. Further, ocular effect models using molecular data from specific cellular systems are needed to develop dose-response correlations. We here describe the current status of PK/PBPK as well as PD models for the eyes and discuss cellular systems, data repositories, as well as animal models in ophthalmology. The application of the various concepts is highlighted for the development of new treatments for postoperative fibrosis after glaucoma surgery.

MR microscopy of the developing upper extremity of the chicken in ovo using 7 Tesla MRI.

MR microscopy (MRM) is known as ultra-high-field (UHF) magnetic resonance imaging with an in-plane spatial resolution of <100 µm, yields highly resolved non-invasive anatomical imaging and allows longitudinal assessment of embryonic avian development. The aim of the present study was to evaluate the feasibility of in vivo anatomical MRI assessment of the developing upper extremity of the chicken. Thirty-eight fertilized chicken eggs were examined at 7 Tesla acquiring high-resolution T2-weighted images with an in-plane resolution of 74 × 74 µm. To reduce motion artefacts, the eggs were moderately cooled before and during MRI. Development of the upper extremity was anatomically and quantitatively assessed. Chondrification and ossification on MRI were correlated with histological examination. MRM allowed the identification of the embryo from stage D5 onwards. First chondrification of the upper extremity was visible at stage D7, and the differentiation of the forearm was possible from stage D9 throughout the developmental period with excellent correlation to histology. MRM also allowed the differentiation between cortical and medullary bone as well as the detection of chondrified areas. UHF MRM allows the in vivo and in ovo evaluation of the upper limb during embryonic development and provides non-invasive longitudinal anatomical information. This technique allows longitudinal studies of the same embryo during the developmental period and may therefore provide further insights into the development of the upper extremity. With improved coil technique and increasing availability of UHF MR systems, there is great potential regarding several research topics in experimental musculoskeletal radiology.

Micro-CT in ophthalmology: ex vivo preparation and contrasting methods for detailed 3D-visualization of eye anatomy with special emphasis on critical point drying.

Background: Micro-computed tomography (micro-CT) provides detailed 3-dimensional (3D) visualization of anatomical structures and encourages morphological reinvestigation of organs with delicate features. The low radiodensity of soft tissues necessitates preceding sample preparation to conduct X-ray imaging with decent contrast between different tissues. In this study, we demonstrate the preparation with three radiopaque agents in combination with elimination of liquids by critical point drying (CPD) introduced for ocular samples. Methods: Enucleated porcine eyes were prepared with ethanolic iodine (EI), aqueous iodine-potassium iodide, or ethanolic phosphotungstic acid (EPTA). Micro-CT scans of the samples were conducted in a moist environment with an isotropic resolution of 9.2-12.5 µm voxel size. Subsequently, samples were chemically dehydrated and critical point (CP) dried to conduct a second scan in a dry environment with a resolution up to 4.7-5.4 µm in voxel size. The visualization effects were qualitatively and semi-quantitatively evaluated with regard to the generated contrast between different ocular tissues. Results: All three contrast agents accumulated well in most of the investigated ocular tissues and lead to an increased X-ray attenuation which allowed for differentiated visualization of ocular structures. Problematic agent penetration into the lens was obvious for iodine-potassium iodide and EPTA. Artificial damages of the lens and thickness reduction for the cornea and sclera due to CPD were noticed. The effects of the different contrasting treatments are described and compared with regard to the effects of CPD. Exclusively CP dried samples that were not treated with contrast agents could also be visualized excellently with a good distinction of different ocular structures from each other. Conclusions: All ocular structures can be visualized by micro-CT. To contrast moist samples, the best results were achieved with iodine potassium iodide (IPI). CPD improved the scan quality in all cases. Even without pretreatment with contrasting agents, the CP dried samples showed a contrast similar to the IPI treated samples.

Ophthalmic Ultrasonography in Sub-Saharan Africa-A Kinshasa Experience.

The aim of this study was to analyze the use of the diagnostic B-scan ultrasound. Should it be made accessible to all surgical centers in Sub-Saharan Africa in order to (i) avoid unnecessary cataract surgery and (ii) evaluate extraocular pathology? This study was conducted in Kinshasa from 2006 to 2019. Three hundred and twenty-three patients were included and separated into two groups. Group 1 included 262 patients with dense cataract. Group 2 consisted of 61 patients with pathologies of the ocular adnexa, and all were examined with a B-scan ultrasound. In group 1, there were 437 systematically screened eyes. Three hundred and ninety-eight eyes (91.08%) showed no abnormalities, 13 (2.97%) retinal detachments were identified, and 15 (3.43%) demonstrated a detached posterior hyaloid membrane. In the second group, 61 patients were examined (group 2). In 20 of them, surgery was performed for biopsy, tumor excision, mucoceles drainage, and palliative treatment. The need for routine B-scan examinations in dense cataract patients seems to be limited and can most likely be replaced by a thorough application of locally available examination techniques. B-scan application is recommended to manage orbital patients in the most cost-effective way.

Predictive value of retinal function by the Purkinje test in patients scheduled for cataract surgery in Kinshasa, DR Congo.

AIM: To assess the retinal function in patients with dense cataracts in resource poor settings in Kinshasa, DR Congo. METHODS: In a tertiary eye care center, the Purkinje entoptic test was performed as part of the ophthalmological examination in 98 eyes in patients with cataract, using a penlight. Totally 92 cataract patients including 86 patients suffered from unilateral and 6 from bilateral cataracts were included in the study. The investigator asked the patients about their perception of the vascular pattern most commonly described as a leafless or dead tree. Visual acuity≥6/60 was considered an indication of good visual function and visual acuity<6/60 of poor function. Following small incision cataract surgery, best corrected visual acuity (BCVA) was determined and compared with the preoperative findings. RESULTS: Out of 98 eyes, there were 80 (81.6%) where the Purkinje entoptic phenomenon was reported by the patients. After cataract surgery, out of the 80 eyes, there were 75 (93.8%) with a BCVA of better than 6/60, whereas in 5 eyes (6.2%), BCVA was 6/60 or less. Out of the 18 eyes (18.4%) where no Purkinje tree was recognized, there were 14 (77.8%) with BCVA of better than 6/60, whereas in 4 (22.2%) BCVA was 6/60 or less. CONCLUSION: The Purkinje entoptic test is successfully used for preoperative assessment of retinal function in patients with dense cataract. However, further investigation and refinement of the test is necessary to validate the method for use in sub-Saharan conditions.

Ultrahigh field MRI determination of water diffusion rates in ex vivo human lenses of different age.

BACKGROUND: The development of presbyopia is correlated with increased lens stiffness. To reveal structural changes with age, ultrahigh field magnetic resonance imaging (UHF-MRI) was used to analyze water diffusion in differently aged human lenses ex vivo. METHODS: After enucleation lens extractions were performed. Lenses were photographed, weighed, and embedded in 0.5% agarose dissolved in culture medium. UHF-MRI was conducted to analyze anatomical characteristics of the lens using T2-weighted Turbo-RARE imaging and to obtain apparent diffusion coefficients (ADC) measurements. A Gaussian fit routine was used to examine the ADC histograms. RESULTS: An age-dependent increase in lens wet weight, lens thickness, and lens diameter was found (P<0.001). T2-weighted images revealed a hyperintense lens cortex and a gradually negative gradient in signal intensity towards the nucleus. ADC histograms of the lens showed bimodal distributions (lower ADC values mainly located in the nucleus and higher ADC values mainly located in the cortex), which did not change significantly with age [ßPeak1=1.96E-7 (-20E-7, 10E-7), P=0.804 or ßPeak2=15.4E-7 (-10E-7, 40E-7), P=0.276; respectively]. CONCLUSIONS: Clinically relevant age dependent lens hardening is probably not correlated with ADC changes within the nucleus, which could be confirmed by further measurements.

Morphological characterization of the human corneal epithelium by in vivo confocal laser scanning microscopy.

BACKGROUND: Regarding the growing interest and importance of understanding the cellular changes of the cornea in diseases, a quantitative cellular characterization of the epithelium is becoming increasingly important. Towards this, the latest research offers considerable improvements in imaging of the cornea by confocal laser scanning microscopy (CLSM). This study presents a pipeline to generate normative morphological data of epithelial cell layers of healthy human corneas. METHODS: 3D in vivo CLSM was performed on the eyes of volunteers (n=25) with a Heidelberg Retina Tomograph II equipped with an in-house modified version of the Rostock Cornea Module implementing two dedicated piezo actuators and a concave contact cap. Image data were acquired with nearly isotropic voxel resolution. After image registration, stacks of en-face sections were used to generate full-thickness volume data sets of the epithelium. Beyond that, an image analysis algorithm quantified en-face sections of epithelial cells regarding the depth-dependent mean of cell density, area, diameter, aggregation (Clark and Evans index of aggregation), neighbor count and polygonality. RESULTS: Imaging and cell segmentation were successfully performed in all subjects. Thereby intermediated cells were efficiently recognized by the segmentation algorithm while efficiency for superficial and basal cells was reduced. Morphological parameters showed an increased mean cell density, decreased mean cell area and mean diameter from anterior to posterior (5,197.02 to 8,190.39 cells/mm2; 160.51 to 90.29 µm2; 15.9 to 12.3 µm respectively). Aggregation gradually increased from anterior to posterior ranging from 1.45 to 1.53. Average neighbor count increased from 5.50 to a maximum of 5.66 followed by a gradual decrease to 5.45 within the normalized depth from anterior to posterior. Polygonality gradually decreased ranging from 4.93 to 4.64 sides of cells. The neighbor count and polygonality parameters exhibited profound depth-dependent changes. CONCLUSIONS: This in vivo study demonstrates the successful implementation of a CLSM-based imaging pipeline for cellular characterization of the human corneal epithelium. The dedicated hardware in combination with an adapted image registration method to correct the remaining motion-induced image distortions followed by a dedicated algorithm to calculate characteristic quantities of different epithelial cell layers enabled the generation of normative data. Further significant effort is necessary to improve the algorithm for superficial and basal cell segmentation.

Atypical Cellular Elements of Unknown Origin in the Subbasal Nerve Plexus of a Diabetic Cornea Diagnosed by Large-Area Confocal Laser Scanning Microscopy.

In vivo large-area confocal laser scanning microscopy (CLSM) of the human eye using EyeGuidance technology allows a large-scale morphometric assessment of the corneal subbasal nerve plexus (SNP). Here, the SNP of a patient suffering from diabetes and associated late complications was analyzed. The SNP contained multiple clusters of large hyperintense, stellate-shaped, cellular-like structures. Comparable structures were not observed in control corneas from healthy volunteers. Two hypotheses regarding the origin of these atypical structures are proposed. First, these structures might be keratocyte-derived myofibroblasts that entered the epithelium from the underlying stroma through breaks in Bowman's layer. Second, these structures could be proliferating Schwann cells that entered the epithelium in association with subbasal nerves. The nature and pathophysiological significance of these atypical cellular structures, and whether they are a direct consequence of the patient's diabetic neuropathy/or a non-specific secondary effect of associated inflammatory processes, are unknown.

Prevalence and patterns of childhood ocular morbidity in Kinshasa. A population-based study.

Context: Childhood ocular disorders can seriously impact on development and education, future employment opportunities and quality of life, their consequences are especially severe in low resource settings. There is a lack of data on pattern and prevalence of ocular morbidities among children in Democratic Republic of the Congo (DRC). Objective: The aim of this study was to determine the pattern and magnitude of childhood ocular disorders in children in Kinshasa, the capital city of DRC. Methods: A population-based cross-sectional study was conducted from July to August 2017. Children aged less than 16 years old were screened by volunteers in households and those with ocular pathologies were examined by two ophthalmologists. Prevalence and pattern of ocular diseases were determined. Results: A total of 4307 households were visited by the surveyors and 13,197 children were screened. Ocular pathologies were diagnosed among 399 children. Girls represented 50.7% of the children and the mean age ± SD was 9.2 ± 4.1 years. The overall prevalence of ocular morbidity in our population was 3.6% [95% CI 3.3-3.9]. Allergic conjunctivitis was the most frequent pathology (56.2%) followed by refractive errors (27.4%) and strabismus (5%). Age of children was the only risk factor with a significant impact on the frequency of ocular pathology. Forty-five percent of children had never benefited from any treatment, self-medication, and recourse to traditional treatments concerned respectively 18.%, and 2.3% of children. Conclusion: Childhood ocular morbidity in Kinshasa city was dominated by allergic conjunctivitis and refractive errors. The frequency of these conditions varies depending on the age of the children. Very few parents consult medical staff when their children have ocular problems, ignorance and limited financial resources are the principal barriers to consult.

Age-Related Changes of the Human Crystalline Lens on High-Spatial Resolution Three-Dimensional T1-Weighted Brain Magnetic Resonance Images In Vivo.

Purpose: To reveal age-related changes of the human crystalline lens by using high-spatial resolution T1-weighted brain magnetic resonance imaging of patients under general anesthesia. Methods: We retrospectively identified 47 children (2-17 years) and 30 adults (18-70 years) without diabetes or eye disease, who required brain magnetic resonance imaging examinations under general anesthesia between 2012 and 2019. Normalized signal intensity of the crystalline lens and vitreous body, as well as equatorial diameter and axial thickness of the lens were assessed by using a three-dimensional T1-weighted magnetization prepared rapid acquisition gradient echo sequence of the brain with 0.9-mm spatial resolution. Patient dossiers were reviewed to record indication for magnetic resonance imaging examination and hypertension. Results: Advancing age was significantly correlated with increasing equatorial diameter of the infantile lens (r = 0. 74; 95% confidence interval, 0.58-0.85; P < .0001) and increasing crystalline lens signal intensity of the adult lens (r = 0.38; 95% confidence interval, 0.02-0.65; P = .0382), which remained significant after accounting for potential confounding variables. There was no significant correlation between age and axial thickness or vitreous body signal intensity in the children and adult cohort. Conclusions: The present study demonstrated that advancing age was significantly correlated with an increasing equatorial diameter of the infantile lens and with increasing crystalline lens signal intensity of the adult lens. These normative data can contribute to our understanding of age-related changes in eye health and function, especially in regard to the emmetropization process and should also be taken into account when investigating lens pathologies.

In vivo Histology of the Cornea - from the "Rostock Cornea Module" to the "Rostock Electronic Slit Lamp" - a Clinical "Proof of Concept" Study. / In-vivo-Histologie der Hornhaut ­ vom "Rostocker Cornea Modul" zur "Rostocker Elektronischen Spaltlampe" ­ eine klinische "Proof-of-Concept"-Studie.

INTRODUCTION: Confocal in vivo microscopy is an established method in ophthalmology research. As it requires contact coupling and calibration of the instruments is suboptimal, this method has been only rarely used in clinical routine work. As a result of close collaboration between physicists, information scientists and ophthalmologists, confocal laser scanning microscopy (CLSM) of the eye has been developed in recent years and a prototype can now be used in patients. The present study evaluates possible clinical uses of this method. MATERIAL AND METHODS: The essential innovations in CLSM are (1) a newly designed coupling element with superficial adaptation to corneal curvature and (2) the use of a dual computerised piezo drive for rapid and precise focusing. In post-processing and after elastic imaging registration of the individual images parallel to the surface, it is also possible to produce sagittal sections resembling a split lamp and with resolution in the micrometer range. The concept was tested on enucleated pig bulbi and tested on normal volunteers and selected patients with diseases of the cornea. RESULTS: Simultaneous imaging in planes parallel to the surface and in sagittal planes provided additional information that can help us to understand the processes of wound healing in all substructures of the cornea and the role of immune competent cells. Possible clinical uses were demonstrated in a volunteer with healthy eyes and several groups of patients (keratoconus after CXL, recurrent keratitis, status after PRK). These show that this new approach can be used in morphological studies at cellular level in any desired and appropriate test plane. CONCLUSIONS: It could be shown that this new concept of CLSM can be used clinically. It can provide valuable and novel information to both preclinical researchers and to ophthalmologists interested in corneal disease, e.g. density of Langerhans cells and epithelial stratification in ocular surface diseases.

Multiwavelength confocal laser scanning microscopy of the cornea.

Confocal reflectance microscopy has demonstrated the ability to produce in vivo images of corneal tissue with sufficient cellular resolution to diagnose a broad range of corneal conditions. To investigate the spectral behavior of corneal reflectance imaging, a modified laser ophthalmoscope was used. Imaging was performed in vivo on a human cornea as well as ex vivo on porcine and lamb corneae. Various corneal layers were imaged at the wavelengths 488 nm, 518 nm, and 815 nm and compared regarding image quality and differences in the depicted structures. Besides the wavelength- and depth-dependent scattering background, which impairs the image quality, a varying spectral reflectance of certain structures could be observed. Based on the obtained results, this paper emphasizes the importance of choosing the appropriate light source for corneal imaging. For the examination of the epithelial layers and the endothelium, shorter wavelengths should be preferred. In the remaining layers, longer wavelength light has the advantage of less scattering loss and a potentially higher subject compliance.

Non-invasive detection of corneal sub-basal nerve plexus changes in multiple myeloma patients by confocal laser scanning microscopy.

PURPOSE: Confocal laser scanning microscopy (CLSM) is a non-invasive technique for cellular in vivo imaging of the human cornea. CLSM screening was evaluated for early detection of corneal nerve morphology changes and neuropathogenic events in different stage multiple myeloma (MM) patients. As MM patients show disease as well as therapy-related neuropathological symptoms, CLSM potentially provides a tool for non-invasive early detection of neuropathogenic events. CLSM findings were compared with the severity of peripheral neuropathic (PNP) symptoms. METHODS: The study enrolled 25 MM patients in which bilateral ophthalmologic examination was performed including unilateral CLSM. Further peripheral nerve function was clinically evaluated using the conventional neuropathy symptom and neuropathy deficit scores (NDSs). RESULTS: In 18/25 MM patients, CLSM detected atypical morphological appearance of bulb-like enlarged nerve endings in the corneal sub-basal nerve plexus. These neuromas were only found in patients showing moderate to severe PNP, in patients with mild or lacking PNP neuromas were absent. CONCLUSIONS: CLSM provides a novel non-invasive diagnostic tool for identification of neuromas in cancer patients affected by therapy or disease-related neuropathologies, perspectival allowing early neuronal degenerative process detection and monitoring.

Suppression of the TGF-ß pathway by a macrolide antibiotic decreases fibrotic responses by ocular fibroblasts in vitro.

To elucidate and to inhibit post-surgical fibrotic processes after trabeculectomy in glaucoma therapy, we measured gene expression in a fibrotic cell culture model, based on transforming growth factor TGF-ß induction in primary human tenon fibroblasts (hTFs), and used Connectivity Map (CMap) data for drug repositioning. We found that specific molecular mechanisms behind fibrosis are the upregulation of actins, the downregulation of CD34, and the upregulation of inflammatory cytokines such as IL6, IL11 and BMP6. The macrolide antibiotic Josamycin (JM) reverses these molecular mechanisms according to data from the CMap, and we thus tested JM as an inhibitor of fibrosis. JM was first tested for its toxic effects on hTFs, where it showed no influence on cell viability, but inhibited hTF proliferation in a concentration-dependent manner. We then demonstrated that JM suppresses the synthesis of extracellular matrix (ECM) components. In hTFs stimulated with TGF-ß1, JM specifically inhibited α-smooth muslce actin expression, suggesting that it inhibits the transformation of fibroblasts into fibrotic myofibroblasts. In addition, a decrease of components of the ECM such as fibronectin, which is involved in in vivo scarring, was observed. We conclude that JM may be a promising candidate for the treatment of fibrosis after glaucoma filtration surgery or drainage device implantation in vivo.

Assessment of the Efficacy of Microinvasive Glaucoma Surgery Techniques using an Oculopression Stress Test. / Nicht invasiver Belastungstest zur Funktionsprüfung von mikroinvasiven Glaukomdrainage-Implantaten und Laserchirurgie.

BACKGROUND: Glaucoma is one of the most common causes of blindness worldwide. The only evidence-based treatment to slow down the progression of glaucoma is the reduction of intraocular pressure (IOP) using local medication or through surgery. During the last years, a large number of microinvasive glaucoma surgery techniques (MIGS) has been developed, in order to reduce the IOP in glaucoma patients safely and effectively. Until now, efficacy of MIGS has been assessed mainly according to the postoperative IOP and the number of medications used. Results from long-term studies are rare or not available in the majority of the cases. In order to better evaluate the functionality of MIGS, a new examination method has been developed with the help of a new oculopressor device. In this study the efficacy of different MIGS techniques will be examined using the new oculopressor. MATERIAL/METHODS: At first, glaucoma patients that had previously received a MIGS surgery (iStent inject, XEN Stent, ELT) were examined with the new oculopression test. Their results were compared with those of non-operated patients and healthy individuals. Overall, 38 healthy subjects (group 1), 10 non-operated patients (group 2), 19 patients after iStent inject implantation (group 3), 14 patients after XEN Stent implantation (group 4) and 5 patients after ELT (group 5) were examined. The new examination measures the IOP-reduction that occurs after oculopression and can be seen as an indirect measurement of the outflow facility of the eye. RESULTS: The IOP-reduction after oculopression differed among the study groups. Non-operated patients showed a significantly lower IOP-reduction compared to healthy individuals. Patients after iStent inject and XEN stent implantation showed a larger reduction of IOP after oculopression in relation to non-operated patients and their results approximated those of healthy individuals. These patients needed fewer medications postoperatively in relation to non-operated patients. Patients after ELT showed postoperatively a smaller reduction of IOP after oculopression compared to iStent inject and XEN stent patients. CONCLUSION: MIGS can increase the outflow facility of the eye in patients with glaucoma. Though ELT had the lowest impact on the aqueous outflow among the studied procedures in this study. The new test can help in the evaluation of current and further development of new MIGS in the future.

Cataract surgery in Kinshasa-Is there a place for "Monovision"?

OBJECTIVES: Monovision is a method of correcting presbyopia where one eye is focused for far and the other for near vision. It is a simple, cost-effective approach to overcome the loss of accommodation with age and to become spectacles independent. METHODOLOGY: About 50 patients, where bilateral cataract extraction was indicated, were included in this study performed at the St. Joseph's Eye Hospital in Kinshasa (DR Congo). Small incision cataract surgery technique (SICS) was applied with the implantation of 6 mm PMMA lenses in the capsular bag. IOL refractive power choice was made to achieve a post-operative refraction of -0.5 dpt for the eye selected for far vision. The second eye received an implant heading for a post-operative myopia of -1.5 dpt suitable for intermediated and near vision. According to the literature, monovision criteria have been regarded as fulfilled when (a) far vision was 0.5 (logMAR) or better and (b) near vision was P3 (0.40, Decimal 32 cm) or better. Spectacle dependence after bilateral cataract surgery heading for monovision was analysed using a dedicated questionnaire. RESULTS: Out of all 50 patients 22 (44%) fulfilled the above defined criteria of monovision in terms of post-operative refraction and visual acuity. About 19 out of these 22 (86.3%) patients were happy without glasses. Two of them used bifocal spectacles, whereas the remaining patient refused spectacles. About 28 patients did not fulfill monovision criteria. Out of these 28 patients, however, 9 (32.1%) of them are happy without glasses. CONCLUSION: In view of the described local circumstances aiming for monovision after bilateral cataract surgery is a suitable approach to optimise cataract surgical outcomes with no extra costs for surgery but considerable improvement of patient's visual performance in daily life.