[Diagnostics, clinical aspects and genetics of congenital corneal opacities]. / Diagnostik, Klinik und Genetik kongenitaler Hornhauttrübungen.

BACKGROUND: Congenital corneal opacities are comparatively rare diseases with high amblyogenic potential. PURPOSE: The present work provides an overview of the diagnostics, clinical aspects and genetics of congenital corneal opacities. METHODS: A literature search was carried out to compile an overview and illustration with own clinical case examples. RESULTS: Differentiated diagnostics are of high importance in the treatment of patients with congenital corneal opacities. A close cooperation between the medical departments involved and also the parents is absolutely essential. The structured classification of congenital corneal opacities provides the basis for a targeted treatment. DISCUSSION: The causes and the clinical symptoms of congenital corneal opacities are manifold. The correct diagnosis should be made early and in an interdisciplinary manner. Based on this, conservative and surgical treatment measures can be planned and an impending development of amblyopia can be specifically counteracted.

Predictability of success and open conjunctival revision rates in the subsequent eye after XEN45 Gel Stent implantation according to lens status.

PURPOSE: To determine the predictability of success and the risk of open conjunctival revision in the subsequent eye after XEN45 Gel Stent implantation according to lens status. METHODS: This was a retrospective single-centre study involving 132 eyes of 66 participants who had undergone intraocular pressure (IOP)-lowering XEN45 Gel Stent implantation, either as a standalone procedure in phakic and pseudophakic eyes or in combination with phacoemulsification. Successful surgery was defined by three scores: IOP at follow-up < 21 mmHg (score A) or < 18 mmHg (score B) and an IOP reduction > 20% or IOP ≤ 15 mmHg and an IOP reduction ≥ 40% (score C). In all scores, one open conjunctival revision was allowed, and additional repeat surgery was considered a failure. The predictability of success and revision rate depending on the outcome of the first eye were calculated using Bayes' theorem. RESULTS: IOP-lowering did not differ significantly between the first and second eyes. Success rates of standalone surgery in the second eye after successful surgery in the first eye significantly exceed rates after prior failure. For the combined procedure, the rates did not differ significantly. For score A, we determined a 76.6% chance of success following a prior success and a 57.9% chance, if prior surgery failed. The corresponding probabilities were 75% and 59.1% for score B, while 66.7% and 15.7% for score C, respectively. We calculated a 60% risk for revision surgery in the standalone phakic group. If the first eye was not revised, the risk of revision in the subsequent eye was 20%. The corresponding risks were 72.7% and 5% for the standalone procedure in pseudophakic patients and 38.4% and 41.7% for the combined procedure, respectively. CONCLUSION: The results of our study offer a tool to predict the outcome of subsequent eye surgeries based on either the outcome in the initial eye and the type of surgery performed, owing to the high predictive potential.

Graft survival of Descemet membrane endothelial keratoplasty (DMEK) in corneal endothelial decompensation after glaucoma surgery.

PURPOSE: This study aims to assess the results, rebubbling rate, and graft survival after Descemet membrane endothelial keratoplasty (DMEK) with regard to the number and type of previous glaucoma surgeries. METHODS: This is a clinical retrospective review of 1845 consecutive DMEK surgeries between 07/2011 and 08/2017 at the Department of Ophthalmology, University of Cologne. Sixty-six eyes were included: group 1 (eyes with previous glaucoma drainage devices (GDD); n = 27) and group 2 (eyes with previous trabeculectomy (TE); n = 39). Endothelial cell loss (ECL), central corneal thickness, graft failure, rebubbling rate, and best spectacle-corrected visual acuity (BSCVA) up to 3 years after DMEK were compared between subgroups of patients with different numbers of and the two most common types of glaucoma surgeries either GDD or TE or both. RESULTS: Re-DMEK rate due to secondary graft failure was 55.6% (15/27) in group 1 and 35.9% in group 2. The mean graft survival time in group 1 was 25 ± 11 months and 31.3 ± 8.6 months in group 2 (p = 0.009). ECL in surviving grafts in group 1 was 35% (n = 13) at 6 months, 36% at 12 months (n = 8), and 27% (n = 4) at 2 years postoperatively. In group 2, ECL in surviving grafts was 41% (n = 10) at 6 months, 36% (n = 9) at 12 months, and 38% (n = 8) at 2 years postoperatively. Rebubbling rate in group 1 was 18.5% (5/27) and 35.9% (14/39) in group 2 (p = 0.079). CONCLUSION: Eyes with previous GDD had no higher risk for an increased rebubbling rate but a higher risk for a re-DMEK due to secondary graft failure with a mean transplant survival time of about 2 years. Compared to eyes with preexisting glaucoma drainage device, eyes after trabeculectomy had less secondary graft failures and a longer mean graft survival rate.

Impact of failed ab-interno trabeculectomy (trabectome) on subsequent XEN45 gel stent implantation in pseudophakic eyes.

PURPOSE: To determine the impact of failed ab-interno trabeculectomy on the postoperative outcome of subsequent XEN45 gel stent (Allergan, CA, USA) implantation in pseudophakic eyes. METHODS: In this retrospective single-center study, we included 60 pseudophakic eyes from 60 participants who underwent XEN45 gel stent implantation. Thirty eyes each underwent primary stent implantation (control group) or had previously undergone a failed ab-interno trabeculectomy (trabectome group). The groups were matched at a 1:1 ratio based on the following criteria: preoperative and maximum Intraocular pressure (IOP), preoperative medication score, cup/disk-ratio, follow-up time, best-corrected visual acuity at baseline, age, and the proportion of patients classified as primary open angle glaucoma or exfoliation glaucoma. We defined a successful surgery by the following three scores: an IOP reduction > 20% and IOP at the longest follow-up < 21 mmHg (Score A) or < 18 mmHg (Score B) or IOP ≤ 15 mmHg and an IOP reduction ≥ 40% (Score C). One open conjunctival revision was allowed in all scores, and a repeat surgery was considered a failure. RESULTS: Following an average follow-up period of 22 ± 12 months, we observed a mean IOP reduction of 38%, from 23.5 ± 5.2-14.5 ± 5.0 mmHg. Comparative analyses between the groups did not reveal a significant difference in the postoperative IOP, postoperative medication score, side effects, revision rate, repeat surgery rate, or success rate. CONCLUSIONS: Trabectome is a viable first-line procedure for medically uncontrolled glaucoma before filtering ab-interno microstent surgery is considered.

[Glaucoma and nanophthalmos]. / Glaukom und Nanophthalmus.

The term nanophthalmos refers to a clinically small eye that appears morphologically normal. A nanophthalmos is characterized by hyperopia but can also be associated with various secondary pathologies, such as angle-closure glaucoma. In particular, the perioperative risks associated with a nanophthalmic eye necessitate examination of the anatomical characteristics, which can result from the disproportional size of intraocular tissues despite structural normality. These include a small anterior chamber depth, scleral thickening and anomalies of the vein plexus, which are predisposing factors for the formation of angle-closure glaucoma. The resulting therapeutic challenges in the nanophthalmic eye can be countered with iridectomy, lensectomy, vitrectomy and cyclophotocoagulation. The definition, genetics and clinical findings of nanophthalmos are discussed with a focus on the complication of glaucoma and its treatment.

[Microscope-integrated intraoperative optical coherence tomography in examination of pediatric patients under anesthesia]. / Mikroskopintegrierte intraoperative optische Kohärenztomographie bei der Narkoseuntersuchung von pädiatrischen Patienten.

BACKGROUND: The therapeutic principle of examinations of children under general anaesthesia using microscope-integrated optical coherence tomography (MI-OCT) is presented. The aim was to assess novel indications as well as limitations for MI-OCT to enhance ophthalmological examinations of neonates and children under general anesthesia. METHODS: The study was based on a review of the literature from google.scholar.com and PubMed and our own data from a prospective study (Department for Ophthalmology, University of Cologne) of 14 children with anterior and posterior segment anomalies undergoing examinations under anesthesia. Patients were examined using a commercially available MI-OCT device. The study analyzed the general feasibility of MI-OCT for ophthalmological examination of children under general anesthesia for the anterior and posterior eye segments and the benefits of indications and intraoperative findings. RESULTS: The MI-OCT significantly enriched the examinations of children under general anesthesia and delivered additional information not visible with the surgical microscope. Even in situations with a limited anterior chamber view MI-OCT enabled estimation of distances, such as corneal thickness. In addition to influencing therapeutic decisions, in 12/14 children MI-OCT also enabled examination of the thickness of the nerve fibre layer of the optic nerve disc and the retina. CONCLUSION: The data presented here underline the benefit of the intraoperative MI-OCT in ophthalmological examinations of children under general anesthesia. In particular MI-OCT enables examinations of children with corneal opacification, if an ophthalmological examination under general anesthesia becomes necessary.

[Vision Loss after Silicone Oil Surgery]. / Visusverlust nach Silikonölchirurgie.

Silicone oil is an intraocular tamponade that is essential for the treatment of complicated retinal detachment. As a long-term tamponade, it improves retinal reattachment and visual outcome. Unexpectedly, surgery with silicone oil tamponade may result in irreversible visual loss of unknown origin. In this report, we provide a general overview of unexplained visual loss after surgery with silicone oil. The frequency of such reports has increased continuously in recent years. The German Retina Society - supported by Retinanet (http://retina-net.uni-koeln.de) - has initiated data collection to gather information about such cases, in cooperation with Cologne University Eye Hospital. Ophthalmologists can provide data about cases of unexplained visual loss anonymously via the "Cologne Clinical Trials Centre" or via augenklinik-silikonoel@uk-koeln.de.

Low-temperature benchtop-synthesis of all-inorganic perovskite nanowires.

A facile, low-temperature precipitation-based method is utilized for the synthesis of ultra-thin and highly uniform cesium lead bromide perovskite nanowires (NWs). The reactions facilitate the NWs' crystalline nature over micron-size lengths, while they impart tailored nanowire widths that range from the quantum confinement regime (∼7 nm) down to 2.6 nm. This colloidal synthesis approach is the first of its kind that is carried out on the work-bench, without demanding chemical synthesis equipment. Importantly, the NWs' photoluminescence is shown to improve over time, with no requirement for tedious post-synthesis surface treatment.

[Intraoperative optical coherence tomography in corneal and glaucoma surgical procedures]. / Intraoperative optische Kohärenztomographie bei hornhaut- und glaukomchirurgischen Eingriffen.

BACKGROUND: Optical coherence tomography (OCT) is the clinical gold standard for anterior and posterior segment imaging. Since OCT devices have been integrated into surgical microscopes, this technique is also available intraoperatively in anterior segment surgery. OCT is well established in imaging very thin or transparent structures as they appear in corneal or glaucoma surgery. Therefore, intraoperative OCT can deliver important information for the surgeon which is superior to the normal surgical microscope. OBJECTIVES: In the present work, an overview about the opportunities of intraoperative OCT in cornea and glaucoma surgery are presented. MATERIAL AND METHODS: The recent literature (PubMed) and our own experience at the Center for Ophthalmology, University Hospital of Cologne are analysed. RESULTS: Intraoperative OCT enables real-time imaging during corneal and glaucoma surgery. Several clinical studies exist, indicating its benefit, e. g. in DMEK, DALK, DSAEK, Boston Keratoprosthesis, canaloplasty or trabectome surgery. Several structures, not visible in the surgical microscope, can be visualized using intraoperative OCT. CONCLUSIONS: As a real-time and high-resolution imaging device, intraoperative online OCT delivers additional information in glaucoma and corneal surgery, compared to the normal operating microscope. Nonetheless one of the main problems is the shadowing produced by surgical instruments. Today the main limitation is the lack of randomized-controlled clinical trials, evaluating the benefit of microscope-integrated intraoperative OCT, compared to the microscope.

[Intraoperative optical coherence tomography for examination of newborns and infants under general anesthesia]. / Intraoperative optische Kohärenztomographie bei Narkoseuntersuchungen von Säuglingen und Kleinkindern.

BACKGROUND: Examination of newborn and children under general anesthesia is essential to prevent amblyopia and blindness; however, the validity was often limited due to a lack of state of the art diagnostic tools in the intraoperative set-up, e. g. optical coherence tomography (OCT). Since OCT devices have been integrated into surgical microscopes, this technique is also available for examination with patients under general anesthesia. OBJECTIVE: To give an overview about the possibilities of intraoperative OCT (iOCT) during examination of newborn and infant children under general anesthesia. MATERIAL AND METHODS: Analysis of recent literature (PubMed) and initial experiences at the Center for Ophthalmology of the University Hospital of Cologne. RESULTS: The use of iOCT enables real-time high-resolution imaging during examinations of children under general anesthesia. All relevant structures of the anterior eye segment (including cornea, lens, chamber angle and iris) can be visualized. Especially when the anterior chamber view is limited due to corneal opacifications, iOCT can deliver important information in addition to that obtained using a surgical microscope. This information is important for the further therapy of the patients. CONCLUSION: Online iOCT is a useful extension of the normal surgical microscope, especially for examination of children under general anesthesia and limited view into the anterior chamber. In our experience it also makes sense to transfer this technique to anomalies of the posterior pole because high-resolution imaging of the macula and optic nerve head is possible.

[Postoperative Follow-Up of Glaucoma Drainage Devices]. / Nachsorge von epibulbären Glaukomdrainageimplantaten.

There is an increasing trend towards using glaucoma drainage implants. The postoperative management of such devices depends on their technical characteristics and specific complications. The Baerveldt glaucoma implant with its larger surface area has been shown to lower mean intraocular pressure more effectively than the Ahmed-FP7 implant. As a non-valve implant, however, it has been associated with a higher rate of severe complications, particularly ocular hypotension. Moreover, glaucoma implants may induce diplopia if they interfere with extraocular muscles. Topical treatment with antibiotics and steroids is necessary in cases of intraocular inflammation. In refractory cases, the tube may even have to be removed. Surgical reposition of the tube may be indicated when it is severely dislocated. Increased intraocular pressure is primarily treated by pressure-lowering medications during postoperative follow-up. If topical glaucoma medication is insufficient to control increases in intraocular pressure due to encapsulation, a second implant may be considered or the capsule surrounding the implant may be excised to reduce outflow resistance or additional cyclodestructive procedures can be performed. Chronic hypotension may be treated with tube ligation or occlusion. Severe corneal oedema may require lamellar keratoplasty. Conjunctival erosions with tube exposure or tube retractions also require surgical correction.

[Complexities of Medical Glaucoma Therapy--the Elderly Patient in Focus]. / Umsetzung und Schwierigkeiten bei Tropftherapien--der ältere Glaukompatient im Fokus.

In order to treat glaucoma with medication successfully, the patient needs to participate actively in the process. "Adherence", formerly "compliance", describes the willingness and capacity to follow the prescribed regimen every day. It is not trivial to measure adherence and persistence, as this quite often relies on self reports by the patient or speculations by the physician. Hence, the overall reported adherence may vary from 5 to 95 %. In general, the following categories have been defined for reduced adherence: medication-related factors, patient-related factors, environmental factors and social factors. Age has been found to intensify or modify many of these factors. Older adults often face various challenges, due to motor disabilities, reduced visual acuity or impaired cognitive capabilities. In patients with movement disorders or tactile limitations, the target area can be reached more successfully with standard eye drop bottles than with single-use dose units. This should be considered if antiglaucoma eye drops are prescribed in the elderly. Frequency of application is a main factor influencing adherence. Monotherapy--as provided with prostaglandins--or drops with a fixed combination have proven to support adherence significantly. A significant boost for self-monitoring activities is initiated by the growing market of electronic devices, like smartphones. For instance, they can provide acoustic alarms as reminders to apply the eye drops. It is evident that any external support or disease-related information by family members, the medical practitioners, support groups or even electronic devices may improve adherence and persistence, even in patients with severe impairments.

Ferrimagnetic nanocrystal assemblies as versatile magnetic particle hyperthermia mediators.

Colloidal nanocrystal assemblies (nanoclusters), consisting of 13 nm iron oxide nanocrystals, were synthesized in various sizes (45-98 nm), and were investigated as heating mediators for magnetic particle hyperthermia. The colloidal nanocrystal clusters show enhanced heating efficiency in comparison with their constituent primary iron oxide nanocrystals due to collective magnetic features. The fine tuning of intra-cluster magnetic interactions results to the domination of the hysteresis losses mechanism over the relaxation loss heating contributions and eventually to a versatile magnetic particle hyperthermia mediator.

[Current aspects on the management of normal tension glaucoma]. / Aktuelle Aspekte zum Management des Normaldruckglaukoms.

In a considerable proportion of glaucoma patients (25-50 %) the intraocular pressure (IOP) is not elevated higher than 22 mmHg at first diagnosis and during subsequent follow-up controls. Although the IOP level remains in the low range < 22 mmHg, progression of glaucoma can still occur. A multitude of different factors are assumed to be involved in glaucoma progression, such as very low nocturnal diastolic blood pressure values, a low mean ocular perfusion pressure, extensive fluctuations in perfusion (e.g. in cases of vascular dysregulation), an increased vulnerability of the optic nerve support structures, an increased translaminar pressure gradient and various underlying systemic diseases. The most important evidence-based aspect of treatment in normal tension glaucoma is pharmaceutical or surgical reduction of the IOP by 30 % or more in comparison to the initial pressure level. Vascular and neuroprotective concepts of treatment for normal tension glaucoma have been strongly advocated and the object of experimental and clinical studies. As yet a clear clinical benefit has not been proven by large prospective randomized studies.

Magnetic inhomogeneity on a triangular lattice: the magnetic-exchange versus the elastic energy and the role of disorder.

Inhomogeneity in the ground state is an intriguing, emergent phenomenon in magnetism. Recently, it has been observed in the magnetostructural channel of the geometrically frustrated α-NaMnO2, for the first time in the absence of active charge degrees of freedom. Here we report an in-depth numerical and local-probe experimental study of the isostructural sister compound CuMnO2 that emphasizes and provides an explanation for the crucial differences between the two systems. The experimentally verified, much more homogeneous, ground state of the stoichiometric CuMnO2 is attributed to the reduced magnetoelastic competition between the counteracting magnetic-exchange and elastic-energy contributions. The comparison of the two systems additionally highlights the role of disorder and allows the understanding of the puzzling phenomenon of phase separation in uniform antiferromagnets.

[Glaucoma filtering surgery in the elderly over eighty years old: an analysis of postoperative risks]. / Antiglaukomatöse Filtrationschirurgie bei alten Glaukompatienten ab dem 80. Lebensjahr: Analyse der postoperativen Risiken.

BACKGROUND: Aim of this retrospective study was to identify the postoperative complications following trabeculectomy with mitomycin C in patients aged 80 years or older at the time of surgery. Additionally, the corresponding risk factors for postoperative complications were analysed. MATERIAL AND METHODS: During a defined period between 2005 and 2009 all trabeculectomies in this age group at the Department of Ophthalmology, University of Cologne were identified. Second eye surgery and re-trabeculectomies in the same eye were excluded from data collection. Postoperative ocular hypotony (< 6 mmHg) and hypertony (> 20 mmHg), bleeding, corneal erosion, re-surgery and prolonged postoperative duration of hospital stay were defined as complications. RESULTS: One hundred and twenty eyes of 120 patients were included. The mean age was 83.4 years, 62.5 % patients were female. Eighty nine percent of the eyes were pseudophakic, the mean visual field defect was - 17.3 dB, the mean preoperative intraocular pressure under pressure-reducing medication was 24.1 mmHg. Considering the perioperative complications there was no significant difference depending on the age (80-85 years, n = 79 and > 85 years, n = 41), depending on the type of anesthesia (general, n = 80 and local, n = 40) or depending on antiplatelet (APT)/anticoagulative (ACT) therapy (APT, n = 55 and ACT, n = 16). The postoperative duration of the hospital stay showed significant correlations with the occurrence of corneal erosions, postoperative ocular hypertony, loss of anterior chamber and choroidal detachment. CONCLUSIONS: The postoperative risks of antiglaucomatous filtering surgery did not increase with age or comorbidity. However, even minor perioperative complications had direct implications on the duration of the hospital stay.

Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS.

Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds.

[Clinical value of ab-interno trabecular surgery in the management of glaucoma]. / Stellenwert der Ab-interno-Trabekelchirurgie in der Glaukombehandlung.

Ab-interno trabecular surgery does not damage sclera and conjunctiva in glaucoma patients and does not prejudice subsequent anti-glaucomatous filtration or drainage device surgery. As only trabecular resistance is surgically modified, the level of intraocular pressure (IOP) can usually not be reduced in the lower teens. Consequently, incisional ab-interno trabecular surgery is a valuable option in early glaucoma stages with moderate IOP elevation, especially in combination with cataract surgery. Ab-interno trabecular surgery is an insufficient surgical tool in normal pressure glaucoma, but also in glaucoma patients with very high IOP peaks.