Comparison of Pre- and Post-DMEK Keratometry and Total Keratometry Values for IOL Power Calculations in Eyes Undergoing Triple DMEK

PURPOSE

To evaluate prediction accuracy of pre- and post-DMEK keratometry (K) and total keratometry (TK) values for IOL power calculations in Fuchs endothelial corneal dystrophy (FECD) eyes undergoing DMEK with cataract surgery (triple DMEK).

METHODS

Retrospective cross-sectional multicenter study of 55 FECD eyes (44 patients) that underwent triple DMEK between 2019 and 2022 between two centers in USA and Europe. Swept-source optical coherence tomography biometry (IOLMaster 700) was used for pre- and post-DMEK measurements. K and TK values were used for power calculations with ten formulae (Barrett Universal II (BUII), Castrop, Cooke K6, EVO 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay I, Kane, and SRK/T). Mean error, mean absolute error (MAE), standard deviation, and percentage of eyes within ±0.50/±1.00 diopters (D) were calculated. Studied formulae were additionally adjusted using a method published previously (IOLup1D Method), which increases the IOL power by 1D. While both eyes from the same patient were considered for descriptive statistics, we restricted to one eye per individual (44 eyes for statistical comparisons.

RESULTS

MAEs for all formulae were lower for post-DMEK K and TK than pre-DMEK K and TK by an average of 0.24 and 0.47 D, respectively. The lowest MAE was 0.49 D for Kane using post-DMEK TK, and the highest MAE was 1.05 D for BUII using pre-DMEK TK. Most IOLup1D formulae had lower MAEs than pre-DMEK K and TK formulae.

CONCLUSIONS

The IOLup1D Method should be used instead of pre-DMEK K and TK values for triple DMEK in FECD eyes. Using post-DMEK TK values for cataract surgery after DMEK provides better refractive accuracy than any of the three studied methods used for triple DMEK procedures.

3D Mapping of the DMEK Detachment Area from OCT Scans of the Anterior Segment of the Eye - Clinical Applications

Graft detachment is the most common complication after Descemet membrane endothelial keratoplasty (DMEK). To assess the amount of graft detachment, precision is limited when using slit-lamp biomicroscopy. Detachment of DMEK grafts can be assessed automatically on anterior segment optical coherence tomography (AS OCT) images and allows visualization of the area and volume of detachment using 3D maps. This article provides an overview of its applications such as accurately assessing the course of natural graft attachment, identification of potential risk factors for detachment and evaluation of the long-term effect of graft detachment. The 3D map of DMEK detachment may support researchers and clinicians in precise quantification of the area and volume of graft detachment even in large data sets, and the intuitive, fast and reliable evaluation.

Automatic inference of ICD-10 codes from German ophthalmologic physicians' letters using natural language processing

Physicians' letters are the optimal source of diagnoses for registries. However, most registries demand for diagnosis codes such as ICD-10. We herein describe an algorithm that infers ICD-10 codes from German ophthalmologic physicians' letters. We assess the method in three German eye hospitals. Our algorithm is based on the nearest-neighbor method as well as on a large thesaurus for ICD-10 codes. This thesaurus was embedded into a Word2Vec space created from anonymized physicians' reports of the first hospital. For evaluation, each of the three hospitals sent all diagnoses taken from 100 letters. The inferred ICD-10 codes were evaluated for correctness by the senders. A total of 3332 natural language terms had been sent in (812 hospital one, 1473 hospital two, 1047 hospital three). A total of 526 non-diagnoses were excluded upfront. 2806 ICD-10 codes were inferred (771 hospital one, 1226 hospital two, 809 hospital three). In the first hospital, 98% were fully correct and 99% correct at the level of the superordinate disease concept. The percentages in hospital two were 69% and 86%. The respective numbers for hospital three were 69% and 91%. Our simple method is capable of inferring ICD-10 codes for German natural language diagnoses, especially when the embedding space has been built with physicians' letters from the same hospital. The method may yield sufficient accuracy for many tasks in the multi-centric setting and can easily be adapted to other languages/specialities.

Atopic Keratoconjunctivitis: Pathophysiology, Clinic, and Potential New Therapeutic Concepts

Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease with a bipolar age distribution in childhood, adolescence and middle adulthood. Up to 50% of AD patients show ocular involvement, which can be potentially sight threatening. Clinically, the majority of cases present with atopic blepharo(kerato)conjunctivitis or atopic keratoconjunctivitis (AKC); other clinical variants from this group of inflammatory ocular surface diseases are keratoconjunctivitis vernalis in childhood and adolescence and allergic conjunctivitis. In addition to the aforementioned blepharitis, keratitis and conjunctivitis, AD is also associated with eyelid involvement with subsequent eyelid malposition, limbal insufficiency with the development of pseudopterygia, (chronic) cicatrizing conjunctivitis with symblephara formation and fornix shortening, as well as ocular surface malignancies such as conjunctival intraepithelial neoplasia (CIN) and squamous cell carcinoma. In addition, an association with AD or AKC has been described for keratoconus. Whereas the therapy of AD in dermatology has made revolutionary advances in recent years through the use of biologicals, the primary use of these biologicals in ophthalmological complications is still very hesitant. Treatment here is often provided using topical steroids and calcineurin inhibitors. The following article summarises recent developments in basic and clinical dermatological research and discusses them in the context of current concepts for ophthalmological therapy.

Qualitätskontrolle in der Hornhautbank mit KI: Vergleich des neuen Deep-Learning-basierten Ansatzes mit der konventionellen Endothelzelldichtenbestimmung durch das Rhine-Tec System

Die Endothelzelldichte ist ein objektiver Parameter für die Freigabe von Hornhauttransplantaten zur Operation. In der Lions Hornhautbank Baden-Württemberg wird für diese Quantifizierung das "Rhine-Tec Endothelial Analysis System" verwendet, das auf der Methode des festen Zählrahmens basiert und nur eine kleine Stichprobe von 15 bis 40 Endothelzellen berücksichtigt. Das Messergebnis hängt daher von der Platzierung des Zählrahmens und der manuellen Nachkorrektur der im Zählrahmen gewerteten Zellen ab. Um den Stichprobenumfang zu erhöhen und eine höhere Objektivität zu schaffen, haben wir auf Grundlage von "Deep-Learning" eine neue Methode entwickelt, die alle sichtbaren Endothelzellen im Bild vollautomatisch erkennt. Ziel dieser Studie ist der Vergleich dieser neuen Methode mit dem konventionellen Rhine-Tec-System 9.375 archivierte phasenkonstrastmikroskopische Bildaufnahmen von konsekutiven Transplantaten aus der Lions-Hornhautbank wurden mit der Deep-Learning-Methode evaluiert und mit den korrespondierenden archivierten Analysen des Rhine-Tec-Systems verglichen. Zum Vergleich der Mittelwerte wurden Bland Altman- und Korrelationsanalysen durchgeführt. Es ergaben sich vergleichbare Ergebnisse beider Methoden. Die mittlere Differenz zwischen Rhine-Tec-System und der Deep-Learning-Methode betrug lediglich -23 Zellen / Quadratmillimeter (95%-Konfidenzintervall -29 bis -17). Es zeigte sich eine statistisch signifikant positive Korrelation zwischen den beiden Methoden mit 0,748. Auffällig in der Bland-Altman-Analyse waren gehäufte Abweichungen im Zelldichtenbereich zwischen 2000 und 2500 Zellen pro Quadratmillimeter mit höheren Werten beim Rhine-Tec-System. Die vergleichbaren Ergebnisse bezüglich der Zelldichtenmesswerte unterstreichen die Wertigkeit des “Deep-Learning-” basierten Verfahrens. Die Abweichungen im Bereich der formalen Schwelle für eine Transplantatfreigabe von 2000 Zellen pro Quadratmillimeter sind sehr wahrscheinlich durch die höhere Objektivität der Deep-Learning-Methode erklärbar und der Tatsache geschuldet, dass Messrahmen und manuelle Nachkorrektur unter Berücksichtigung des Gesamtbildes aus der Endothelbewertung jeweils gezielt ausgewählt worden waren. Diese vollständige Sichtung des Transplantatendothels und Qualitätsbeurteilung kann aktuell noch nicht durch das Deep-Learning System ersetzt werden, und ist somit weiterhin die wichtigste Grundlage der Transplantatfreigabe zur Keratoplastik. Endothelial cell density (ECD) is a crucial parameter for the release of corneal grafts for transplantation. The Lions Eye Bank of Baden-Württemberg uses the "Rhine-Tec Endothelial Analysis System" for ECD quantification, which is based on a fixed counting frame method considering only a small sample of 15 to 40 endothelial cells. The measurement result therefore depends on the frame placement and manual correction of the cells counted within the frame. To increase the sample size and create higher objectivity, we developed a new method based on "deep learning" that automatically detects all visible endothelial cells in the image. This study aims to compare this new method with the conventional Rhine-Tec system. 9,375 archived phase-contrast microscopic images of consecutive grafts from the Lions Eye Bank were evaluated with the deep learning method and compared with the corresponding archived analyses of the Rhine-Tec system. Specifically, comparisons of means, Bland-Altman and correlation analyses were performed. Comparable results were obtained for both methods. The mean difference between the Rhine-Tec system and the deep learning method was only -23 cells/mm2 (95% confidence interval -29 to -17). There was a statistically significant positive correlation between the two methods with a correlation coefficient of 0.748. Noticeable in the Bland-Altman analysis were clustered deviations in the cell density range between 2000 and 2500 cells/mm2 with higher values in the Rhine-Tec system. The comparable results regarding cell density measurement values underline the validity of the "deep learning" based method. The deviations around the formal threshold for graft release of 2000 cells/mm2 are most likely explained by the higher objectivity of the deep learning method and the fact that measurement frames and manual corrections were specifically selected to reach the formal threshold of 2000 cells/mm2 when the full area endothelial quality was good. This full area assessment of the graft endothelium cannot currently be replaced by deep learning methods and remains the most important basis for graft release for keratoplasty.

Enrichment, Characterization, and Proteomic Profiling of Small Extracellular Vesicles Derived from Human Limbal Mesenchymal Stromal Cells and Melanocytes

Limbal epithelial progenitor cells (LEPC) rely on their niche environment for proper functionality and self-renewal. While extracellular vesicles (EV), specifically small EVs (sEV), have been proposed to support LEPC homeostasis, data on sEV derived from limbal niche cells like limbal mesenchymal stromal cells (LMSC) remain limited, and there are no studies on sEVs from limbal melanocytes (LM). In this study, we isolated sEV from conditioned media of LMSC and LM using a combination of tangential flow filtration and size exclusion chromatography and characterized them by nanoparticle tracking analysis, transmission electron microscopy, Western blot, multiplex bead arrays, and quantitative mass spectrometry. The internalization of sEV by LEPC was studied using flow cytometry and confocal microscopy. The isolated sEVs exhibited typical EV characteristics, including cell-specific markers such as CD90 for LMSC-sEV and Melan-A for LM-sEV. Bioinformatics analysis of the proteomic data suggested a significant role of sEVs in extracellular matrix deposition, with LMSC-derived sEV containing proteins involved in collagen remodeling and cell matrix adhesion, whereas LM-sEV proteins were implicated in other cellular bioprocesses such as cellular pigmentation and development. Moreover, fluorescently labeled LMSC-sEV and LM-sEV were taken up by LEPC and localized to their perinuclear compartment. These findings provide valuable insights into the complex role of sEV from niche cells in regulating the human limbal stem cell niche.

UV light-mediated corneal crosslinking as (lymph)angioregressive pretreatment to promote graft survival after subsequent high-risk corneal transplantation (CrossCornealVision): protocol for a multicenter, randomized controlled trial

BACKGROUND

Good vision highly depends on the transparency of the cornea, which is the "windscreen" of the eye. In fact, corneal blindness due to transparency loss is the second most common cause of blindness worldwide, and corneal transplantation is the main cure. Importantly, the cornea is normally avascular but can secondarily be invaded by pathological (blood and lymphatic) vessels due to severe inflammation, and the survival prognosis of a corneal graft mainly depends on the preoperative vascular condition of the recipient's cornea. Whereas transplants placed into avascular recipient beds enjoy long-term survival rates of > 90%, survival rates significantly decrease in pathologically pre-vascularized, so-called high-risk recipients, which account for around 10% of all performed transplants in Germany and > 75% in lower and middle-income countries worldwide.

METHODS

This parallel-grouped, open-randomized, multicenter, prospective controlled exploratory investigator-initiated trial (IIT) intends to improve graft survival by preconditioning pathologically vascularized recipient corneas by (lymph)angioregressive treatment before high-risk corneal transplantation. For this purpose, corneal crosslinking (CXL) will be used, which has been shown to potently regress corneal blood and lymphatic vessels. Prior to transplantation, patients will be randomized into 2 groups: (1) CXL (intervention) or (2) no pretreatment (control). CXL will be repeated once if insufficient reduction of corneal neovascularization should be observed. All patients (both groups) will then undergo corneal transplantation. In the intervention group, remaining blood vessels will be additionally regressed using fine needle diathermy (on the day of transplantation). Afterwards, the incidence of graft rejection episodes will be evaluated for 24 months (primary endpoint). Overall graft survival, as well as regression of corneal vessels and/or recurrence, among other factors, will be analyzed (secondary endpoints).

DISCUSSION

Based on preclinical and early pilot clinical evidence, we want to test the novel concept of temporary (lymph)angioregressive pretreatment of high-risk eyes by CXL to promote subsequent corneal graft survival. So far, there is no evidence-based approach to reliably improve graft survival in the high-risk corneal transplantation setting available in clinical routine. If successful, this approach will be the first to promote graft survival in high-risk transplants. It will significantly improve vision and quality of life in patients suffering from corneal blindness.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05870566. Registered on 22 May 2023.

XEN®-45 implantation for refractory uveitic glaucoma

PURPOSE

To evaluate the efficacy of XEN®-45 gel stent ab interno implantation for medically uncontrolled uveitic glaucoma.

METHODS

Retrospective analysis of 25 eyes receiving XEN® gel stent for medically uncontrolled uveitic glaucoma from February 2019 to February 2023 with recording of intraocular pressure (IOP) values, ocular hypotensive medication, requirement for revision or secondary surgery and complications. Prerequisites for XEN® implantation were a clear cornea, an open iridocorneal angle and an unscarred, mobile conjunctiva at the implantation site. Minimum follow-up required for inclusion was 3 months. The primary outcome measure was IOP compared to baseline. Complete and qualified success were defined as final IOP of ≤ 18 mmHg without or with topical antiglaucomatous treatment, respectively. Failure was defined as IOP > 18 mmHg on two consecutive visits, IOP reduction < 20%, persisting complications from hypotony and open conjunctival bleb revision. Further glaucoma surgical intervention was defined as complete failure.

RESULTS

Mean preoperative IOP was 35.3 ± 10.9 mmHg on 2.9 ± 0.9 topical antiglaucomatous agents. 19 of 25 patients (76%) received additional oral acetazolamide. 19 eyes were pseudophakic, 5 eyes phakic and 1 aphakic. Early postoperatively, mean IOP reduced to 7.7 ± 3.0 mmHg (75.8% reduction). At final follow-up (mean 17.7 months) mean IOP was 12.0 ± 3.8 mmHg (62.5% reduction) on 0.2 ± 0.6 medications. Six eyes (24%) required bleb revision at mean 28 weeks and therefore were categorized as failure. One eye failed despite bleb revision and restart of topical ocular hypotensive medication. Three other eyes (12%) had IOP spikes with uveitis flare-ups. Transient hypotony complications occurred in 32%. At final follow-up, 18 eyes (72%) achieved complete success and one eye (4%) qualified success.

CONCLUSION

The XEN® gel stent effectively reduced IOP in uncontrolled uveitic glaucoma, with 72% complete success. Bleb revision was required in 24%. IOP spikes occurred in 12% despite functioning blebs. Further follow-up is needed to determine long-term outcomes.

[Global ophthalmology : Update]

The aim of global ophthalmology is to maximize vision, ocular health and functional ability, thereby contributing to overall health and well-being, social inclusion and quality of life of every individual worldwide. Currently, an estimated 1.1 billion people live with visual impairment, 90% of which can be prevented or cured through largely cost-effective interventions. At the same time, 90% of people affected live in regions with insufficient eye health coverage. This challenge drove the World Health Organization (WHO) and a group of nongovernmental organizations to launch "VISION 2020: the Right to Sight", a global campaign which recently concluded after 20 years. The achievements, challenges and lessons learned were identified and incorporated into the current campaign "2030 IN SIGHT".

Increasing hospitalisation of patients with herpes zoster ophthalmicus-an interdisciplinary retrospective analysis

BACKGROUND

The occurrence of herpes zoster is rising globally. Future trends will be influenced by changes in population demographics and the growing number of patients at risk. Overall this poses a challenge for healthcare systems.

METHODS

In our interdisciplinary, single-centre retrospective analysis, we aimed to assess the burden of the disease within the Department of Dermatology and the Eye Centre from the Medical Centre, University of Freiburg from 2009-2022. We obtained data from 3034 cases coded using the ICD-10 B02.x. Patients were characterised by sex, age, year of treatment, and type of treatment (inpatient vs. outpatient).

RESULTS

Overall we observed a 200% increase in the number of herpes zoster patients over the 13-year period. Upon closer analysis, this was mainly due to a rise in inpatient treatment for herpes zoster ophthalmicus.

CONCLUSIONS

If the incidence of herpes zoster ophthalmicus continues to increase at the current rate the number of hospitalisations of zoster ophthalmicus would double by 2040, assuming guideline-appropriate treatment. Overall, the results show a growing need for inpatient ophthalmological care.

[Bacterial Conjunctivitis: Current Aspects of Diagnosis and Therapy]

Bacterial conjunctivitis is a leading cause of infectious conjunctivitis in children and second most common cause in adults. Although often self-limiting, it can lead to complications like corneal scarring and systemic infections in high-risk groups including newborns and immunocompromised patients. Thus, prompt diagnosis and treatment are essential for these vulnerable populations. Common bacterial causes are Staphylococcus aureus and Streptococcus pneumoniae in adults and Haemophilus influenzae and Moraxella catarrhalis in children. Clinical features alone do not reliably identify the causative pathogen. Microbiological testing is necessary for persistent or severe cases. Topical antibiotics like azithromycin or fluorochinolones are usually prescribed. However, gonococcal and chlamydial conjunctivitis warrant systemic antibiotics due to their potential for severe complications. Increasing antibiotic resistance might even necessitate tailored therapy based on antibiotic susceptibility profiles. Screening and treating pregnant women is an effective prevention strategy by reducing perinatal transmission (especially of gonococcal and chlamydial infections). In summary, while often self-limiting, potential complications and rising antibiotic resistance underscore the importance of timely diagnosis and treatment of bacterial conjunctivitis. Preventive measures including maternal screening are crucial public health initiatives to curb the risks associated with this common eye infection.

ZEISS PLEX Elite 9000 Widefield Optical Coherence Tomography Angiography as Screening Method for Early Detection of Retinal Hemangioblastomas in von Hippel-Lindau Disease

Purpose

To evaluate early detection of retinal hemangioblastomas (RHs) in von Hippel-Lindau disease (VHLD) with widefield optical coherence tomography angiography (wOCTA) compared to the standard of care in ophthalmologic VHLD screening in a routine clinical setting.

Methods

We conducted prospective comparisons of three screening methods: wOCTA, standard ophthalmoscopy, and fluorescein angiography (FA), which was performed only in uncertain cases. The numbers of detected RHs were compared among the three screening methods. The underlying causes for the lack of detection were investigated.

Results

In 91 eyes (48 patients), 67 RHs were observed (mean, 0.74 ± 1.59 RH per eye). FA was performed in eight eyes. Ophthalmoscopy overlooked 25 of the 35 RHs detected by wOCTA (71.4%) due to the background color of the choroid (n = 5), small tumor size (n = 13), masking by a bright fundus reflex (n = 2), and masking by surrounding retinal scars (n = 5). However, wOCTA missed 29 RHs due to peripheral location (43.3%). The overall detection rates were up to 37% on the basis of ophthalmoscopy alone, up to 52% for wOCTA, and 89% for FA. Within the retinal area covered by wOCTA, the detection rates were up to 46.7% for ophthalmoscopy alone, up to 92.1% for wOCTA, and 73.3% for FA.

Conclusions

The overall low detection rate of RHs using wOCTA is almost exclusively caused by its inability to visualize the entire peripheral retina. Therefore, in unclear cases, FA is necessary after ophthalmoscopy.

Translational Relevance

Within the imageable retinal area, wOCTA shows a high detection rate of RHs and therefore may be suitable to improve screening for RHs in VHLD.

Transcriptional profiling specifies the pathogen-specific human host response to infectious keratitis

Purpose

Corneal infections are a leading cause of visual impairment and blindness worldwide. Here we applied high-resolution transcriptomic profiling to assess the general and pathogen-specific molecular and cellular mechanisms during human corneal infection.

Methods

Clinical diagnoses of herpes simplex virus (HSV) (n=5) and bacterial/fungal (n=5) keratitis were confirmed by histology. Healthy corneas (n=7) and keratoconus (n=4) samples served as controls. Formalin-fixed, paraffin-embedded (FFPE) human corneal specimens were analyzed using the 3' RNA sequencing method Massive Analysis of cDNA Ends (MACE RNA-seq). The cellular host response was investigated using comprehensive bioinformatic deconvolution (xCell and CYBERSORTx) analyses and by integration with published single cell RNA-seq data of the human cornea.

Results

Our analysis identified 216 and 561 genes, that were specifically overexpressed in viral or bacterial/fungal keratitis, respectively, and allowed to distinguish the two etiologies. The virus-specific host response was driven by adaptive immunity and associated molecular signaling pathways, whereas the bacterial/fungal-specific host response mainly involved innate immunity signaling pathways and cell types. We identified several genes and pathways involved in the host response to infectious keratitis, including CXCL9, CXCR3, and MMP9 for viral, and S100A8/A9, MMP9, and the IL17 pathway for bacterial/fungal keratitis.

Conclusions

High-resolution molecular profiling provides new insights into the human corneal host response to viral and bacterial/fungal infection. Pathogen-specific molecular profiles may provide the foundation for novel diagnostic biomarker and therapeutic approaches that target inflammation-induced damage to corneal host cells with the goal to improve the outcome of infectious keratitis.

Diurnal Variation of Visual Acuity and Refraction in Fuchs Endothelial Corneal Dystrophy

PURPOSE

Patients with advanced Fuchs endothelial corneal dystrophy frequently report poor vision in the morning, which improves as the day progresses. This study quantified the amount of variation in near and distance visual acuity and refraction over the course of a day.

METHODS

This was a prospective cohort study. Best-corrected distance visual acuity and near visual acuity were tested in participants with clinically advanced Fuchs dystrophy and in controls with healthy corneas. Subjective refraction and autorefraction were conducted in a presumed steady state in the afternoon. Measurements were repeated directly after eye opening in the hospital the next morning. In a subgroup, measurements were repeated every 30 minutes for up to 2 hours.

RESULTS

In Fuchs dystrophy, the mean distance visual acuity was worse by -3 letters (95% confidence interval, -4 to -1) directly after eye opening in the morning compared with late afternoon. No such difference was seen in healthy corneas. In Fuchs dystrophy, visual acuity improved over the course of the study. Visual acuity in the morning could be improved with fine tuning of refraction, and refractive changes were exclusive to Fuchs dystrophy (0.5-1.0 D in spherical equivalent in 30%, >1.0 D in 2% of eyes).

CONCLUSIONS

Distance and near visual acuity and refraction changes over the course of the day in patients with advanced Fuchs dystrophy. Although small changes in refraction may not usually require a second set of glasses for the first hours of the day, diurnal variation should be considered when determining disease severity in routine practice and in clinical trials.

Supine Positioning for Graft Attachment After Descemet Membrane Endothelial Keratoplasty: A Randomized Controlled Trial

PURPOSE

The Supine Positioning for Descemet Membrane Endothelial Keratoplasty Attachment (SUPER-DMEK) trial assessed the efficacy of prolonged supine head positioning on graft attachment.

DESIGN

Randomized controlled trial.

METHODS

Participants with Fuchs' dystrophy were randomized to 5 days of supine head positioning (intervention) or to 1 day (control). Participants, surgeons, and investigators were masked until the day after surgery. Adherence to the allocated intervention was monitored using a head sensor. Main outcome measures were area and volume of graft detachment (coprimary end points) 2 weeks after surgery quantified using a validated neural network for image segmentation on anterior segment optical coherence tomography images, and repeat air injection (rebubbling), subjective visual function, and adverse events (secondary end points).

RESULTS

A total of 86 participants received the allocated intervention (35 eyes intervention and 51 eyes control). In the intention-to-treat analysis, the mean area of graft detachment was 28.6% in the intervention arm and 27.5% in the control arm (adjusted between-arm difference, 1.3; 95% CI, -8.7 to 11.4; P = .80). Results for volume of detachment and as-treated analyses based on head position sensor data indicated no potentially clinically relevant effect of prolonged supine positioning on graft attachment. Results were not compatible with a relevant treatment effect on rebubbling or subjective visual function. Adverse events, most commonly back pain, were more common and more severe with the intervention.

CONCLUSIONS

In this randomized controlled trial, graft attachment was not improved with prolonged supine head positioning. Prolonged supine positioning frequently caused back pain. Prolonged supine positioning after Descemet membrane endothelial keratoplasty for Fuchs' dystrophy may not be needed in routine practice.

HIF1α and HIF2α immunoreactivity in epithelial tissue of primary and recurrent pterygium by immunohistochemical analysis

PURPOSE

Hypoxia-inducible factors (HIFs) are considered to play a significant role in the pathogenesis of pterygium. The aim of this study was to investigate the relative expression or immunoreactivity of HIF1α and HIF2α in the epithelium of primary pterygium, recurrences and healthy conjunctiva.

METHODS

Immunohistochemical staining was performed with antibodies against HIF1α and HIF2α, respectively, on 55/84 primary pterygium specimens, 6/28 recurrences and 20/20 control tissues (healthy conjunctiva).

RESULTS

Immunohistochemical staining revealed lower epithelial immunoreactivity of HIF1α and HIF2α in both primary pterygium (11% and 38%) and recurrences (18% and 21%) when compared to healthy conjunctival tissue (46% and 66%). Differences between immunoreactivity of HIF1α and of HIF2α in primary pterygium and controls were each highly significant (p < .001). Within the group of primary pterygium, epithelial immunoreactivity of HIF2α (38%) was significantly higher than that of HIF1α (11%). In recurrent pterygium and healthy conjunctiva, immunoreactivity levels of HIF2α were higher than those of HIF1α as well; however, differences between both isoforms were not significant.

CONCLUSION

Our study shows evidence that the higher expressed epithelial HIF2α, rather than HIF1α, and the balance between both HIF isoforms might be relevant factors associated with pathogenesis of primary pterygium. Modulation of HIF2α levels and activity may thus offer a new therapeutic approach to the treatment of advancing pterygium where the initial stage with its HIF1-peak has already passed.

Influence of Organ Culture on the Characteristics of the Human Limbal Stem Cell Niche

Organ culture storage techniques for corneoscleral limbal (CSL) tissue have improved the quality of corneas for transplantation and allow for longer storage times. Cultured limbal tissue has been used for stem cell transplantation to treat limbal stem cell deficiency (LSCD) as well as for research purposes to assess homeostasis mechanisms in the limbal stem cell niche. However, the effects of organ culture storage conditions on the quality of limbal niche components are less well described. Therefore, in this study, the morphological and immunohistochemical characteristics of organ-cultured limbal tissue are investigated and compared to fresh limbal tissues by means of light and electron microscopy. Organ-cultured limbal tissues showed signs of deterioration, such as edema, less pronounced basement membranes, and loss of the most superficial layers of the epithelium. In comparison to the fresh limbal epithelium, organ-cultured limbal epithelium showed signs of ongoing proliferative activity (more Ki-67+ cells) and exhibited an altered limbal epithelial phenotype with a loss of N-cadherin and desmoglein expression as well as a lack of precise staining patterns for cytokeratin ((CK)14, CK17/19, CK15). The analyzed extracellular matrix composition was mainly intact (collagen IV, fibronectin, laminin chains) except for Tenascin-C, whose expression was increased in organ-cultured limbal tissue. Nonetheless, the expression patterns of cell-matrix adhesion proteins varied in organ-cultured limbal tissue compared to fresh limbal tissue. A decrease in the number of melanocytes (Melan-A+ cells) and Langerhans cells (HLA-DR+, CD1a+, CD18+) was observed in the organ-cultured limbal tissue. The organ culture-induced alterations of the limbal epithelial stem cell niche might hamper its use in the treatment of LSCD as well as in research studies. In contrast, reduced numbers of donor-derived Langerhans cells seem associated with better clinical outcomes. However, there is a need to consider the preferential use of fresh CSL for limbal transplants and to look at ways of improving the limbal stem cell properties of stored CSL tissue.

Needs and Satisfaction Analysis of Patients and Referring Physicians in an Outpatient Cataract Service

BACKGROUND

To ensure efficient use of resources within outpatient services, constant patient flow is vital. This can be achieved by addressing the wishes and needs of all relevant stakeholders.

MATERIALS AND METHODS

The present study aims to show how the needs and present satisfaction of patients and referring physicians can be determined in the context of an outpatient cataract service. It presents the conclusions that can be drawn for the design of the service. To assess needs and satisfaction, we developed a patient questionnaire and a referring physician questionnaire. Promoters and detractors for referral were identified following the concept of the net promoter score, a market research instrument.

RESULTS

339 (38%) patients and 26 (45%) referring physicians of the main referring group answered the questionnaires. The most important characteristics for referring physicians were quality of treatment, patient satisfaction, and communication in case of queries as well as speed of sending the doctor's letter. When making their decision on a cataract centre, the patients prioritised professional reputation, previous experience with the clinic, and recommendation of their ophthalmologist as well as customary appointment scheduling.

CONCLUSION

The two groups influence each other's recommendation or choice. Simultaneous analysis of patients and referring physicians is therefore essential. Overall, patients and referring physicians are highly satisfied with the cataract service of the university medical centre. Beyond that, however, various potentials for improvement could be identified. In summary, this report describes a comprehensive approach to assess needs and satisfaction of patients and referring physicians in an outpatient clinic trying to sustainably improve patient care.

Intrastromal Keratolimbal Epithelial Cysts: Congenital and Postsurgical

Two very rare cases of intrastromal keratolimbal epithelial cysts are reported. Firstly, an enlarging congenital cyst in a 9-year-old boy, and secondly, a recurrent postsurgical cyst in an 18-year-old female patient. Both cases presented with a limbal cyst, continuing into the corneal stroma as a whitish mass up to the optical axis. The indication for surgery was stabilization of visual acuity in case one and improvement of cosmetic aspects in case two. In the first case, a small part of the cyst was opened at the limbus and the whitish material in the cyst was flushed out. In the second case, anterior lamellar keratectomy over the whole cyst was performed with subsequent application of mitomycin C. Immunohistochemical analysis revealed cytokeratin 19-positive epithelial cells in both cysts. Therefore, an implantation of conjunctival epithelium into the sclera seems to be responsible for the respective keratolimbal cyst. Postsurgically, satisfying cosmetic and functional results were obtained in both cases, with follow-ups of 4 and 9 months. Keratolimbal cysts have rarely been described in the literature. In most cases, a conjunctival epithelial implantation occurs following surgery or trauma and very rarely congenitally. After simple aspiration of the cyst's content, a rapid recurrence is often observed, so that partial or - if possible - complete removal of the anterior cyst wall is recommended, as shown in our cases.

Addressing bias in manual segmentation of spheroid sprouting assays with U-Net

Purpose

Angiogenesis research faces the issue of false-positive findings due to the manual analysis pipelines involved in many assays. For example, the spheroid sprouting assay, one of the most prominent in vitro angiogenesis models, is commonly based on manual segmentation of sprouts. In this study, we propose a method for mitigating subconscious or fraudulent bias caused by manual segmentation. This approach involves training a U-Net model on manual segmentations and using the readout of this U-Net model instead of the potentially biased original segmentations. Our hypothesis is that U-Net will mitigate any bias in the manual segmentations because this will impose only random noise during model training. We assessed this idea using a simulation study.

Methods

The training data comprised 1531 phase contrast images and manual segmentations from various spheroid sprouting assays. We randomly divided the images 1:1 into two groups: a fictitious intervention group and a control group. Bias was simulated exclusively in the intervention group. We simulated two adversarial scenarios: 1) removal of a single randomly selected sprout and 2) systematic shortening of all sprouts. For both scenarios, we compared the original segmentation, adversarial segmentation, and respective U-Net readouts. In the second step, we assessed the sensitivity of this approach to detect a true positive effect. We sampled multiple treatment and control groups with decreasing treatment effects based on unbiased ground truth segmentation.

Results

This approach was able to mitigate bias in both adversarial scenarios. However, in both scenarios, U-Net detected the real treatment effects based on a comparison to the ground truth.

Conclusions

This method may prove useful for verifying positive findings in angiogenesis experiments with a manual analysis pipeline when full investigator masking has been neglected or is not feasible.

[Training concept for personnel in a university outpatient clinic: development and evaluation of a structured introductory training concept]

BACKGROUND

The training of new employees is crucial for effective interaction and commitment to the company.

OBJECTIVE

Development and evaluation of a structured induction into the process flows of a university outpatient clinic.

MATERIAL AND METHODS

We developed and tested a two-stage model for getting to know staff, premises, nursing and medical process flows, and learning examination techniques: Participants went through all stages of an outpatient clinic visit as fictitious patients and subsequently evaluated learning success by self-assessment of general (process-related) and specific (examination-related) competencies in writing and in a feedback interview.

RESULTS

In this study, 11 residents, 8 operating room nursing staff, and 6 students underwent the training program. The self-assessed level of competence before and after the run-through as well as the extent of the increase in competence varied depending on the stage and professional group. Residents and students experienced a specific increase in general competences (both 98%; nursing personnel 64%). Specific competence gains for residents were particularly evident in becoming familiar with important process-related interfaces between the occupational groups, in software and examination techniques, and in improved orientation in the outpatient clinic (competence gain at 83% of stages). Operating room nursing staff benefited most from improved communication with staff.

CONCLUSION

An increase in general competence can be achieved by a structured training with little time expenditure for different professional groups and facilitates, especially the start for new residents. For maximum specific competence gain, an outpatient clinic run tailored to the employee's field of activity seems desirable.

Developing and validating a questionnaire to assess the symptoms of blepharitis accompanied by dry eye disease

PURPOSE

To propose additional items for established dry eye disease (DED) instruments that cover blepharitis-specific signs and symptoms and to determine the association between the clinical findings and subjective complaints.

METHODS

Thirty-one patients with blepharitis and DED were prospectively included in the pretest period for selecting suitable questions. In the main phase of the study, the selected questions were then tested on 68 patients with blepharitis and DED and 20 controls without blepharitis or DED. Pearson's coefficient of correlation was calculated between the blepharitis-specific questions, tear break-up time (TBUT), the Schirmer test score, and the ocular surface disease index (OSDI) score; and the similarity between the blepharitis-specific questions, OSDI questions, and objective parameters for DED was assessed via hierarchical clustering. Furthermore, the discriminatory power of the blepharitis-specific questions was investigated with the receiver operating characteristic (ROC) curve.

RESULTS

The additional question about heavy eyelids revealed a significant correlation with the OSDI score (r = 0.45, p < 0.001) and Schirmer score (r =  - 0.32, p = 0.006). Cluster analysis demonstrated the similarity between the question about heavy eyelids and TBUT. In addition, the OSDI questionnaire had the highest discriminatory power in ROC analysis, and the OSDI score significantly correlated with the specific questions about eyelids sticking together (r = 0.47, p < 0.0001) and watery or teary eyes (r = 0.34, p = 0.003).

CONCLUSIONS

The blepharitis-specific additional questions were closely associated with objective parameters for DED. The question about heavy eyelids might be well suited for recording the symptoms of hyposecretory and hyperevaporative dry eye with blepharitis.

Slow Interstitial Fluid Flow Activates TGF-β Signaling and Drives Fibrotic Responses in Human Tenon Fibroblasts

BACKGROUND

Fibrosis limits the success of filtering glaucoma surgery. We employed 2D and 3D in vitro models to assess the effects of fluid flow on human tenon fibroblasts (HTF).

METHODS

HTF were exposed to continuous or pulsatile fluid flow for 48 or 72 h, at rates expected at the transscleral outflow site after filtering surgery. In the 2D model, the F-actin cytoskeleton and fibronectin 1 (FN1) were visualized by confocal immunofluorescence microscopy. In the 3D model, mRNA and whole cell lysates were extracted to analyze the expression of fibrosis-associated genes by qPCR and Western blot. The effects of a small-molecule inhibitor of the TGF-β receptor ALK5 were studied.

RESULTS

Slow, continuous fluid flow induced fibrotic responses in the 2D and 3D models. It elicited changes in cell shape, the F-actin cytoskeleton, the deposition of FN1 and activated the intracellular TGF-β signaling pathway to induce expression of fibrosis-related genes, such as CTGF, FN1 and COL1A1. ALK5-inhibition reduced this effect. Intermittent fluid flow also induced fibrotic changes, which decreased with increasing pause duration.

CONCLUSIONS

Slow interstitial fluid flow is sufficient to induce fibrosis, could underlie the intractable nature of fibrosis following filtering glaucoma surgery and might be a target for antifibrotic therapy.

Caruncle dysgeneses - A case series

Purpose

Caruncle dysgeneses are extremely rare and must be differentiated from caruncular and conjunctival tumors. Very few case reports with histopathological descriptions exist. In this case series, four patients with five caruncle dysgeneses, two with histopathological findings, are characterised.

Observations

Patient 1, a 26-year-old woman, presented with a conjunctival change at the left lower eyelid she had first noticed seven months earlier. She reported foreign body sensation and itching. On her left eye was a subtarsal conjunctival tumour measuring approximately 4 × 4 mm with whitish sebaceous gland-like inclusions located almost in the fornix morphologically resembling the nearby caruncle. The patient was asymptomatic after excision. Histopathological examination of the excised tissue showed non-keratinizing squamous epithelium with goblet cells. Subepithelially, there was lymphoplasmacytic cellular infiltration with intervening epidermal cysts adjacent to sebaceous glands and underlying adipose tissue, but no hair follicles or sweat/lacrimal glands. The epidermal cysts contained scattered hairs. A diagnosis of supernumerary caruncle was made.Patient 2, a 56-year-old woman, was referred for evaluation of a caruncle tumour that was reported to be present since childhood. Clinically the 5 × 5 mm measuring tumour appeared yellowish and less reflective compared to the normal caruncle tissue. Histopathologically, non-keratinizing squamous epithelium with goblet cells was found. In the area of more exposed tumour tissue, there were significantly fewer goblet cells and incipient keratinization of the superficial epithelial layers. Subepithelially, sebaceous glands and adipocytes were present. Hair follicles or sweat/lacrimal glands were not evident. A diagnosis of megacaruncle was made.Patient 3, a 58-year-old woman with Goldenhar syndrome, was clinically diagnosed with a supernumerary caruncle on the right eye as an incidental finding.Patient 4, a 24-year old man, clinically presented with a megacaruncle on the right eye and a supernumerary caruncle on the left.

Conclusions

Caruncle dysgeneses are often asymptomatic and have to be differentiated from other caruncular and conjunctival tumors. If they are present, attention should be paid to signs of an oculo-auriculo-vertebral spectrum as Goldenhar syndrome. In case of unclear findings or complaints, excision with subsequent histopathological examination is required.

Indications, techniques, and graft survival of mini and corneo-scleral tectonic keratoplasties: A retrospective single-center case series

PURPOSE

Tectonic keratoplasties (TK) are used to treat corneal and scleral perforations and to prevent the loss of the eye. In this study, we retrospectively analyzed indications, surgical procedures, and outcomes of eccentric mini and corneo-scleral tectonic keratoplasties with respect to anatomical survival and clear graft survival rates to identify risk factors for graft failure.

METHODS

This retrospective study includes 33 eccentric mini (graft diameter <6 mm) and/or corneo-scleral TK of 32 consecutive patients of a total of 41 TK carried out between 2005 and 2020 in the Eye Center, University of Freiburg, Germany, making up 0.7% of all keratoplasties performed during this period (n = 5557). Patient and graft specific data were extracted from medical files. Anatomical survival-defined as achieving integrity of the globe without further surgical interventions-and clear graft survival-defined as persisting graft clarity-were estimated using the Kaplan-Meier method. We also fitted Cox proportional hazard models to account for factors influencing anatomical and clear graft survival.

RESULTS

Median duration of anatomical success was 72.5 months (95% confidence interval (CI) 18.1-infinite (inf.)) and median duration of clear graft survival was 29.6 months (95% CI 12.5-Inf.). The 1-year survival rate for anatomical survival was 67.6% (95% CI 52.2% - 87.6%) and for clear graft survival 66.4% (95% CI 50.5%- 87.1%). No enucleation was necessary during this time-period. Non-inflammatory primary causes (n = 14) presented a trend towards better anatomical survival rates (median remained above 0.75 during follow-up) compared to inflammatory primary causes (n = 19, median 18.1 months (95% CI 2.8 - inf.)) and longer clear graft survival (median 29.6 months (95% CI 12.5 - inf.) versus 13.1 months (95% CI 3.2 - inf.)). Corneo-scleral grafts (n = 18) compared to corneal grafts (n = 15) showed a trend towards better anatomical survival (more than 50% of eyes did not fail during follow-up period (95% CI 21.9-Inf. months) versus 18.1 months (95% CI 2.4-Inf.)) and clear graft survival (median 29.6 months (95% CI 12.6-Inf.) versus 6.2 months (95% CI 2.8-Inf.)). Old age (n = 11, 75.2 - 90.1 years) compared to young age (n = 11, 6.2 - 60.2 years) was the only hazard ratio (hazard ratio 0.04 (95% CI 0.002-0.8)) that reached the level of significance (p = 0.03).

CONCLUSION

Eccentric TK is helpful in the successful treatment of a variety of severe eye diseases. Patients at young age, with pre-existing inflammatory conditions or corneal TK are at higher risk for anatomical failure as well as clear graft failure and therefore need to be monitored closely.

[Conjunctival tumors in children : Histopathological diagnoses in 262 cases]

BACKGROUND

The spectrum of conjunctival tumors in children and adolescents significantly differs from that of adults.

OBJECTIVE

The aim of this study was to show the distribution of histopathological diagnoses of pediatric conjunctival tumors.

MATERIAL AND METHODS

Retrospective case series including all conjunctival tumors of children and adolescents under 18 years of age examined histologically over a period of 25 years (1990-2015) at the Eye Center in Freiburg, Germany.

RESULTS

Among the 262 conjunctival specimens, the most common diagnoses were conjunctival nevi (148, [56%]), most often with junctional activity (106/148, [72%]), pyogenic granulomas (26, [10%]), and dermolipomas (18, [7%]). In one case a malignant tumor (conjunctival melanoma) was detected (1, < 1%).

CONCLUSION

The results suggest that pediatric conjunctival tumors are benign in most cases. Most of them were of melanocytic origin, with a junctional conjunctival nevus being the most common diagnosis.

XEN®-63 Compared to XEN®-45 Gel Stents to Reduce Intraocular Pressure in Glaucoma

The XEN® gel stent reduces intraocular pressure (IOP) in glaucoma. XEN®-45 is widely used; the newer XEN®-63 has a larger lumen targeting potentially lower IOP outcomes. We retrospectively compared the first 15 XEN®-63 cases to 15 matched XEN®-45 controls. With a preoperative IOP of 18.1 ± 3.9 mmHg (mean ± SD) and a final IOP of 9.1 ± 2.0 mmHg, XEN®-63 implantation resulted in an IOP reduction of 44.6 ± 16.5%. Similarly, with a preoperative IOP of 18.3 ± 4.5 mmHg and a final IOP of 10.3 ± 2.1 mmHg, XEN®-45 implantation resulted in an IOP reduction of 40.1 ± 17.2%. The median follow-up period was 204 days (range 78-338 days) for the XEN®-63 group and 386 days (range 99-1688 days) for the XEN®-45 group. In total, 5/15 eyes of each group underwent open conjunctival bleb revision within the period of observation. Three eyes of the XEN®-63 group had secondary glaucoma surgery. One eye in the XEN®-63 group and three eyes in the XEN®-45 group required a restart of antiglaucomatous medication. In conclusion, both stents effectively lower IOP and medication. XEN®-63 achieved a slightly lower IOP over a short follow-up. Complication and revision rates were similar.

Descemet Membrane Endothelial Keratoplasty in Eyes with an Artificial Iris

The purpose of this study is to report the outcome of Descemet membrane endothelial keratoplasty (DMEK) in three eyes with a complex anterior segment and an artificial iris. A retrospective chart review of three cases was performed and clinically meaningful patient characteristics, clinical events, and therapeutic interventions were outlined. A literature search was performed and the clinical course of the three cases was discussed in the context of the published literature. DMEK in the presence of an artificial iris did not match the clinical results of DMEK in uncomplicated eyes. All three eyes experienced major complications, such as failure to achieve graft adherence, early graft failure, or an immune reaction. The indication for DMEK in complex anterior segments with an artificial iris should be made with the awareness of multiple possible complications and the potentially poor prognosis of the procedure.

Characterization of the Immediate and Delayed Biomechanical Response to UV-A Crosslinking of Human Corneas

PURPOSE

Keratoconus leads to visual deterioration due to irregular astigmatism and corneal thinning. Riboflavin-based corneal UV-A crosslinking (CXL) induces novel intramolecular and intermolecular links resulting in corneal tissue stiffening, thereby halting disease progression. The purpose of this study was to analyze the immediate and delayed biomechanical responses of human donor corneas to CXL.

METHODS

CXL was performed according to the Dresden protocol to corneas not suitable for transplantation. Biomechanical properties were subsequently monitored by measuring the Young modulus using nanoindentation. The immediate tissue response was determined after 0, 1, 15, and 30 minutes of irradiation. Delayed biomechanical effects were investigated with follow-up measurements immediately and 1, 3, and 7 days after CXL.

RESULTS

Young's modulus indicated a linear trend in direct response to increasing irradiation times (mean values: total 61.31 kPa [SD 25.53], 0 minutes 48.82 kPa [SD 19.73], 1 minute 53.44 kPa [SD 25.95], 15 minutes 63.56 kPa [SD 20.99], and 30 minutes 76.76 kPa [SD 24.92]). The linear mixed model for the elastic response of corneal tissue was 49.82 kPa + (0.91 kPa/min × time [minutes]); P < 0.001. The follow-up measurements showed no significant delayed changes in the Young modulus (mean values: total 55,28 kPa [SD 15.95], immediately after CXL 56,83 kPa [SD 18.74], day 1 50.28 kPa [SD 14.15], day 3 57.08 kPa [SD 14.98], and day 7 56.83 kPa [SD 15.07]).

CONCLUSIONS

This study suggests a linear increase of corneal Young modulus as a function of CXL timing. No significant short-term delayed biomechanical changes posttreatment were observed.

Management of Belantamab Mafodotin-Associated Keratopathy With Rigid Gas-Permeable Corneal Contact Lenses

ABSTRACT

Belantamab mafodotin is a relatively new drug used in the treatment of relapsed or refractory multiple myeloma. Clinical studies have shown promising responses, but ocular toxicity remains a major challenge with dose reduction or therapy discontinuation being the only available treatment option. We report a clinical case of a patient with severe keratopathy under therapy with belantamab. The use of rigid gas-permeable corneal contact lenses led to a major visual improvement and enabled therapy continuation at full dose over several months. Although this strategy may not be suitable for all patients, it provides an additional option for the treatment of ocular toxicity of this promising agent.

Cataract Surgery-Indications, Techniques, and Intraocular Lens Selection

BACKGROUND

Opacification of the lens of the eye (cataract) is usually due to aging. It is a painless, progressive condition that affects contrast and color perception and alters refraction, leading to visual loss that may be total. In cataract surgery, the turbid lens is replaced by an artificial lens. An estimated 600 000 to 800 000 such procedures are performed in Germany each year.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, including meta-analyses, Cochrane reviews, and randomized controlled clinical trials (RCTs).

RESULTS

Cataract is the most common reversible cause of blindness around the world (approximately 95 million people). The surgical replacement of a turbid lens with an artificial lens is usually carried out under local anesthesia. The standard technique for fragmentation of the nucleus of the lens is ultrasonic phacoemulsification. RCTs have not shown the superiority of the femtosecond laser over phacoemulsification for this purpose so far. The spectrum of artificial intraocular lenses, aside from the conventional type with a single focus, include lenses with multiple foci, extended-depth-of-focus (EDOF) lenses, and astigmatism-correcting lenses.

CONCLUSION

In Germany, cataract surgery is usually performed on an outpatient basis under local anesthesia. Artificial lenses with various additional functions are available nowadays; the choice of lens depends on the needs of the individual patient. Patients must be adequately informed about the advantages and disadvantages of the different lens systems.

[Keratoconus: biomechanics ex vivo]

BACKGROUND

Keratoconus is associated with an impairment in corneal biomechanics. Using nanoindentation, spatially resolved measurement of biomechanical properties can be performed on corneal tissue. The aim of this study is to assess the biomechanical properties of corneas with keratoconus in comparison to healthy controls.

METHODS

17 corneas with keratoconus and 10 healthy corneas unsuitable for transplantation were included in the study. After explantation, corneas were kept in culture medium containing 15% dextran for at least 24 h. Nanoindentation was then performed to a depth of 25 µm at a force increase of 300 µN/min.

RESULTS

A total of 2328 individual indentations were performed for this study. In the keratoconus group; the mean modulus of elasticity was 23.2 kPa (± 15.0 kPa) for a total of 1802 indentations. In the control group, the mean modulus of elasticity was 48.7 kPa (± 20.5 kPa) with a total of 526 indentations. The Wilcoxon test showed that the differences were statistically significant.

CONCLUSION

Using nanoindentation, a significantly lower elastic modulus was found in corneas with keratoconus compared to corneas without keratoconus. Further studies are needed to gain a better understanding of how keratoconus affects corneal biomechanics.

Efficient Isolation and Expansion of Limbal Melanocytes for Tissue Engineering

Limbal melanocytes (LMs) are found in the corneoscleral limbus basal epithelial layer and interact with neighboring limbal epithelial progenitor cells. The difficulty of isolating and cultivating LMs is due to the small fraction of LMs in the overall limbal population and the frequent contamination of primary cultures by other cell types. This has limited the research on freshly isolated LMs and the investigation of their biological significance in the maintenance of the limbal stem cell niche. Here, we describe an optimized protocol for the efficient isolation and expansion of LMs from cadaveric corneal limbal tissue using CD90 and CD117 as selective markers in fluorescence-activated cell sorting to obtain a pure population of LMs (CD90^- CD117⁺) with self-renewal capacity and sustained melanin production. The isolation of pure LMs from a single preparation enables direct transcriptomic and proteomic analyses, as well as functional studies on freshly isolated LMs, which can be considered the proper counterparts of LMs in vivo and have potential applications in tissue engineering.

Characterization of Porcine Ocular Surface Epithelial Microenvironment

The porcine ocular surface is used as a model of the human ocular surface; however, a detailed characterization of the porcine ocular surface has not been documented. This is due, in part, to the scarcity of antibodies produced specifically against the porcine ocular surface cell types or structures. We performed a histological and immunohistochemical investigation on frozen and formalin-fixed, paraffin-embedded ocular surface tissue from domestic pigs using a panel of 41 different antibodies related to epithelial progenitor/differentiation phenotypes, extracellular matrix and associated molecules, and various niche cell types. Our observations suggested that the Bowman's layer is not evident in the cornea; the deep invaginations of the limbal epithelium in the limbal zone are analogous to the limbal interpalisade crypts of human limbal tissue; and the presence of goblet cells in the bulbar conjunctiva. Immunohistochemistry analysis revealed that the epithelial progenitor markers cytokeratin (CK)15, CK14, p63α, and P-cadherin were expressed in both the limbal and conjunctival basal epithelium, whereas the basal cells of the limbal and conjunctival epithelium did not stain for CK3, CK12, E-cadherin, and CK13. Antibodies detecting marker proteins related to the extracellular matrix (collagen IV, Tenascin-C), cell-matrix adhesion (β-dystroglycan, integrin α3 and α6), mesenchymal cells (vimentin, CD90, CD44), neurons (neurofilament), immune cells (HLA-ABC; HLA-DR, CD1, CD4, CD14), vasculature (von Willebrand factor), and melanocytes (SRY-homeobox-10, human melanoma black-45, Tyrosinase) on the normal human ocular surface demonstrated similar immunoreactivity on the normal porcine ocular surface. Only a few antibodies (directed against N-cadherin, fibronectin, agrin, laminin α3 and α5, melan-A) appeared unreactive on porcine tissues. Our findings characterize the main immunohistochemical properties of the porcine ocular surface and provide a morphological and immunohistochemical basis useful to research using porcine models. Furthermore, the analyzed porcine ocular structures are similar to those of humans, confirming the potential usefulness of pig eyes to study ocular surface physiology and pathophysiology.

[Corneal endothelial cell photography: comparison of smartphones]

BACKGROUND

The documentation of ophthalmologic findings using smartphone photography can confirm diagnoses and enable follow-up assessments in outpatient care. Photographing corneal endothelial cells using a smartphone on a slit lamp is complex for both smartphone and examiner. Smartphone models differ in their ability to quickly and safely take images of the corneal endothelium.

AIM OF THIS WORK

In this paper different smartphone models are presented with respect to their applicability for corneal endothelial cell photography and success factors for good smartphone imaging are described.

MATERIAL AND METHODS

In a cross-sectional study, a selection of 16 different smartphone models were compared with respect to their use in corneal endothelial cell photography. The smartphones were attached to the slit lamp eyepiece using an adjustable adapter. It was tested whether high-quality endothelial cell images of healthy subjects could be obtained within 3 min using the standard photo app of the respective smartphone. In addition, the subjective difficulty of creating the image was recorded. Factors contributing to successful imaging of corneal endothelial cells were summarized in a figure.

RESULTS AND DISCUSSION

Distinct differences regarding feasibility and quality of endothelial cell photography were detected between the different smartphones. Not every smartphone is suitable for endothelial cell photography.

[The economic importance of individual health services (IGeL) in ophthalmology over time: survey results from 2010 and 2020]

BACKGROUND

Individual health services (IGeL) enable patients to receive medical services not covered by social health care; however, there is no central data collection on IGeL in Germany.

OBJECTIVE

This study illustrates the spectrum of IGeL provided in the field of ophthalmology as an example of the importance of IGeL in Germany based on survey results.

MATERIAL AND METHODS

Nationwide, 10% of ophthalmologists in private practice were randomly selected in this anonymous survey in 2010 and 2020 while in 2020 in addition to the randomized 10% of ophthalmologists the same ophthalmologists from 2010 were contacted. By means of a written questionnaire, ophthalmologists were asked about their practice structure, total revenue from IGeL as well as the frequency and price of specific IGeL.

RESULTS

Income from IGeL was estimated at an average of 21% of the regular service volume in 2010 and 23% in 2020. Glaucoma IGeL and medical report IGeL were offered by almost all ophthalmologists and glaucoma screening being performed most frequently with an average frequency of over 150 examinations/month. IGeL, such as HRT IGeL were offered by significantly fewer ophthalmologists in 2020 than in 2010, while IGeL based on other technological procedures such as glaucoma OCT were offered more frequently in 2020.

CONCLUSION

The volume of IGeL provided in established ophthalmological practices was stable between 2010 and 2020. The range of services offered in 2020 compared to 2010 reflects a dynamic change associated with the entry of new technologies into routine care.

DMEK outcome after one year - Results from a large multicenter study in Germany

PURPOSE

Descemet membrane endothelial keratoplasty (DMEK) accounts for >50% of all corneal transplants in Germany. So far, no data from such a large multicenter study have been published.

METHODS

This retrospective study included 3200 DMEKs at seven departments performed for Fuchs endothelial corneal dystrophy (FECD) or bullous keratopathy (BK). We evaluated best corrected visual acuity (BCVA, logMAR), endothelial cell density (ECD, cells/mm² ), minimal corneal thickness (CT, μm), rebubbling-, primary transplant failure- and immune reaction-rate. Changes over time were evaluated by linear mixed models for repeated measures and correlation with case number by center by weighted linear regression.

RESULTS

For patients without vision-limiting comorbidities (74% of all analysed eyes, n = 2270), mean BCVA improved from 0.6 ± 0.4 logMAR to 0.2 ± 0.2 logMAR 6 months (p < 0.001, n = 1441) and 0.1 ± 0.2 logMAR 12 months (p = 0.001, n = 1402) postoperatively. BK- had a worse BCVA compared to FECD-patients (0.3 ± 0.5 vs. 0.1 ± 0.2 logMAR [p < 0.001] at 1 year). ECD declined from 2465 ± 259 cells/mm² (n = 2876 preoperatively) to 1587 ± 433 cells/mm² after 12 months (p < 0.001, n = 1237). Mean rebubbling rate was 0.4 ± 0.7/eye. 784 eyes (25%) received at least one rebubbling. More rebubblings correlated with a lower ECD, a worse BCVA, a higher CT, and higher transplant failure and rejection rates (p < 0.001, p = 0.013 for BCVA at 12 months). A single rebubbling did not influence the BCVA (p = 0.785). Graft failure rate was 3% (n = 67), rejection rate 1.5% (n = 48).

CONCLUSION

Descemet membrane endothelial keratoplasty increases visual acuity with low transplant failure- and rejection-rates. FECD has a better outcome than BK. Since a quarter of all patients need a rebubbling, this should be included in the informed consent. Remarkably, one rebubbling has no influence on the outcome.

Current practice in the treatment of epithelial and melanocytic tumors with Interferon-alpha 2b: a survey among tertiary eye centers in Germany

Purpose: To evaluate the standard of care, in particular the use of topical or subconjunctival Interferon-α2b, in treating ocular surface squamous neoplasia or melanocytic tumors among tertiary eye centers in Germany. Methods: A survey containing 14 questions was sent to 43 tertiary eye centers in Germany. The questions addressed the surgical and medical management of ocular surface squamous neoplasia and melanocytic tumors (primary acquired melanosis and malignant melanoma) as well as the clinical experiences and difficulties in prescribing off-label Interferon-α2b eye drops and subconjunctival injections. Results: Twenty-four tertiary eye centers responded to the survey. Eighty-three percent of centers have used Interferon-α2b in their clinical practice and 25% prescribed it as the first-line cytostatic agent following surgical excision of ocular surface squamous neoplasia, while 10% would do so for melanocytic tumors. Correspondingly, the majority of respondents selected Mitomycin C as their first-line agent. Side effects were uncommon with topical Interferon-α2b eye drops, but were more frequently reported after subconjunctival Interferon-α2b injections. In total, eight centers had experience with Interferon-α2b injections. The most significant obstacles perceived by ophthalmologists when prescribing Interferon-α2b were its high cost and the reimbursement thereof. Conclusion: Off-label Mitomycin C was the preferred adjuvant therapy for epithelial and melanocytic tumors, with Interferon-α2b being the standard second-line option. Interferon-α2b has predominantly been used to treat ocular surface squamous neoplasia and, to a lesser extent, melanocytic tumors at German tertiary eye centers. Following its market withdrawal, supply shortages of Interferon-α2b are likely to have a profound impact on patient care and their quality of life. Ziel: Evaluation des Therapiestandards, insbesondere der Verwendung von topischem oder subkonjunktivalem Interferon-α2b, bei der Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche oder melanozytären Tumoren der Augenoberfläche in tertiären Augenzentren in Deutschland. Methoden: Eine Umfrage mit 14 Fragen wurde an 43 tertiäre Augenzentren in Deutschland verschickt. Die Fragen befassten sich mit der chirurgischen und medizinischen Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche und melanozytären Tumoren (primär erworbene Melanose und malignes Melanom) sowie den klinischen Erfahrungen und Schwierigkeiten bei der Verschreibung von Off-Label Interferon-α2b Augentropfen und subkonjunktivalen Injektionen. Ergebnisse: 24 tertiäre Augenzentren nahmen an der Umfrage teil. 83% der Zentren hatten Interferon-α2b eingesetzt und 25 % verschrieben es als First-Line-Therapie nach chirurgischer Entfernung von Neoplasien der plattenepithelialen, okulären Oberfläche, wohingegen 10 % dies bei melanozytären Tumoren angewendet hätten. Dementsprechend wählte die Mehrheit der Befragten Mitomycin C als Mittel der ersten Wahl aus. Nebenwirkungen waren bei topischen Interferon-α2b Augentropfen selten, wurden aber häufiger nach subkonjunktivalen Interferon-α2b-Injektionen gemeldet. Insgesamt hatten acht Zentren Erfahrungen mit Interferon-α2b-Injektionen. Die größten Hürden, die Augenärzte bei der Verschreibung von Interferon-α2b hinderten waren die hohen Kosten und deren Übernahme durch die Krankenkassen. Schlussfolgerung: Off-label Mitomycin C war die bevorzugte adjuvante Therapie für epitheliale und melanozytäre Tumoren, während Interferon-α2b Standardoption für eine Zweitlinientherapie war. Interferon-α2b wurde in deutschen, tertiären Augenzentren vorwiegend zur Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche und in geringerem Maße von melanozytären Tumoren eingesetzt. Nach der Marktrücknahme von Interferon-α2b werden Lieferengpässe wahrscheinlich beträchtliche Auswirkungen auf die Patientenversorgung und ihre Lebensqualität haben.

Glaucoma Treatment in German Hospitals in 2019

BACKGROUND

Surgical procedures in ophthalmology are subject to fluctuations in their application and are dependent on new developments, availability, and success rates. In the field of glaucoma surgery in particular, numerous new procedures have been introduced over the last few years. So far, hardly any analyses have been done on the current application of these newer procedures. In this paper, we present the extent to which different glaucoma surgery procedures were used in German hospitals in 2019.

METHODS

The quality reports of German hospitals from 2019 were evaluated regarding all glaucoma-specific procedure codes. In particular, laser procedures, "classic" glaucoma procedures, and "modern" procedures such as MIGS (minimally invasive glaucoma surgery) are compared below.

RESULTS

In 2019, 49,031 glaucoma procedures were performed in German hospitals. Numerically, cyclodestructive procedures were used most frequently. MIGS accounted for approximately 10% of procedures according to the available data. Among filtering procedures, about 40% were implant-assisted.

DISCUSSION AND CONCLUSION

On the one hand, the data analyzed show a mixed expansion of the spectrum with newer procedures such as the MIGS and implants; on the other hand, classic procedures such as cyclodestruction are still used. It can be assumed that further shifts in surgical methods will be seen in the coming years.

Web-based gene expression analysis-paving the way to decode healthy and diseased ocular tissue

BACKGROUND

Gene expression analysis using RNA sequencing has helped to improve the understanding of many diseases. Databases, such as the Gene Expression Omnibus database of the National Center for Biotechnology Information provide RNA sequencing raw data from various diseased tissue types but their analysis requires advanced bioinformatics skills. Therefore, specific ocular databases provide the transcriptional profiles of different ocular tissues and in addition enable intuitive web-based data analysis.

OBJECTIVE

The aim of this narrative review is to provide an overview of ocular transcriptome databases and to compare them with the Human Eye Transcriptome Atlas newly established in Freiburg.

METHODS

PubMed literature search.

RESULTS

A total of nine ocular transcriptome databases focusing on different aspects were identified. The iSyTE and Express platforms specialize in gene expression during lens and retinal development in mice, whereas retina.tigem.it, Eye in a Disk, and Spectacle focus on selected ocular tissues such as the retina. Spectacle, UCSC Cell Browser and Single Cell Portal allow intuitive exploration of single cell RNA sequencing data derived from retinal, choroid, cornea, iris, trabecular meshwork and sclera specimens. The microarray profiles of a variety of healthy ocular tissues are included in the Ocular Tissue Database. The Human Eye Transcriptome Atlas provides the largest collection of different ocular tissue types, contains the highest number of ocular diseases and is characterized by a high level of quality achieved by methodological consistency.

CONCLUSION

Ocular transcriptome databases provide comprehensive and intuitive insights into the transcriptional profiles of a variety of healthy and diseased ocular tissues. Thus, they improve our understanding of the underlying molecular mediators, support hypothesis generation and help in the search for new diagnostic and therapeutic targets for various ocular diseases.

Long-Term Outcomes of Excimer Laser-Assisted Penetrating Keratoplasty Using a Commercially Available Laser System - A Retrospective Case Series

BACKGROUND

Favorable functional outcomes have been reported after excimer laser-assisted penetrating keratoplasty (EXL PKP). But this technique has not been widely adopted, and there are reports on EXL PKP from only a very limited number of institutions. Some of these results refer to operations carried out with laser systems that are not commercially available. In this retrospective case series, we report the long-term outcome of EXL PKP using the Schwind Amaris 500E laser system.

MATERIAL AND METHODS

This retrospective consecutive case series included 30 eyes of 29 patients who had undergone EXL PKP between 2010 and 2013. Primary outcome measures were topographic astigmatism and visual acuity. Secondary outcome measures were the rates of graft rejection and graft failure, and the rate of grafts with an endothelial cell density below 500 cells/mm². Survival analyses were carried out for the following endpoints: visual acuity, rate of graft rejection, and rate of grafts with endothelial cell densities higher than 500 cells/mm².

RESULTS

The median interquartile range (IQR) duration of follow-up was 45 (36) months. The indications for PKP were keratoconus (n = 21), corneal scarring (n = 6), Fuchs endothelial dystrophy (n = 1), and corneal dystrophy other than Fuchs endothelial dystrophy (n = 2). The median (IQR) topographic astigmatism at the end of the follow-up period was 5.3 (2.9) D. Forty-five months after surgery, 73% of all eyes had a visual acuity better than 0.3 LogMAR. The rate of graft rejection after 45 months of follow-up was 32%. All eyes maintained endothelial cell densities higher than 500 cells/mm². There was no graft failure.

CONCLUSIONS

EXL PKP is a safe and effective surgical procedure. No general conclusions can be drawn on the refractive outcome of EXL PKP. Potential advantages, such as a higher degree of graft-host congruity, that could possibly improve the refractive outcome should be weighed against the higher costs of EXL PKP.

Graft Detachment after Descemet Membrane Endothelial Keratoplasty with and without Cataract Surgery

PURPOSE

To evaluate graft detachment after Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes and DMEK combined with cataract surgery (triple DMEK).

DESIGN

Analysis of 3 single-center prospective cohort studies and 1 randomized controlled trial.

PARTICIPANTS

Participants with Fuchs' endothelial corneal dystrophy.

METHODS

A validated neural network for image segmentation quantified graft detachment on anterior segment OCT (AS-OCT) images 3 days after DMEK and at the 2-week postoperative visit. Area and volume of graft detachment were compared between DMEK only and triple DMEK using generalized estimating equation models and adjusting for participant age and the size of the air bubble.

MAIN OUTCOME MEASURES

Area and volume of DMEK graft detachment.

RESULTS

Among 207 participants with 270 eyes included, 75 pseudophakic eyes had DMEK only and 195 eyes had triple DMEK. A total of 147 eyes had less than one third of detachment at day 3. In 139 of these eyes (95%), detachment was still less than one third at the 2-week scan, indicating that postoperative graft detachment at 2 weeks occurred mainly in eyes with early detachment. When superimposing all 3-dimensional maps from 2 weeks after surgery, the central graft was mainly attached and detachment was located at the graft margin. The mean area of graft detachment decreased from 28% in DMEK only and 38% in triple DMEK to 16% in DMEK only and 25% in triple DMEK at the 2-week postoperative visit. At 2 weeks, the mean area of detachment was 1.85-fold higher (95% confidence interval [CI], 1.34-2.56) and the mean volume was 2.41-fold higher (95% CI, 1.51-3.86) in triple DMEK compared with DMEK. A total of 46 eyes received rebubbling procedures, with 7 eyes (9%) in the DMEK group and 39 eyes (20%) in the triple DMEK group (adjusted risk ratio, 3.1; 95% CI, 1.3-7.1), indicating that rebubbling was more common in eyes undergoing triple DMEK.

CONCLUSIONS

Automated segmentation of AS-OCT images allowed precise quantification of graft detachment over time and identified DMEK combined with cataract surgery as a risk factor. Frequency of operative follow-up might be guided by extent of detachment in the first postoperative days after DMEK.

[Next-generation sequencing in ophthalmology]

New methods for basic research are finding their way into ophthalmology and expand the options for research, diagnostics and treatment. This article centers on the study of gene activity in cells and tissues by next-generation sequencing (NGS). Following a brief introduction to the basic principles of NGS, this article focuses on transcriptome analysis by RNA sequencing using examples from ophthalmology. The RNA sequencing provides a comprehensive and unbiased overview of gene activity in cells and tissues and thus forms an important foundation for generating new testable scientific hypotheses. It thus contributes to the in-depth characterization of pathological changes and supports the development of new diagnostic and therapeutic approaches.

Transcriptional Profiling Provides New Insights into Organ Culture-Induced Changes in Human Donor Corneas

Corneal transplantation is one of the most common forms of tissue transplantation worldwide. Donor corneal tissue used in transplantation is provided by eye banks, which store the tissue in culture medium after procurement. To date, the effects of cell culture on human corneal tissue have not been fully elucidated. Using the 3' RNA sequencing method for massive analysis of cDNA ends (MACE), we show that cultivation of corneal tissue leads to significant changes in a variety of molecular processes in human corneal tissue that go well beyond aspects of previously known culture effects. Functionally grouped network analysis revealed nine major groups of biological processes that were affected by corneal organ culture, among them keratinization, hypoxia, and angiogenesis, with genes from each group being affected by culture time. A cell type deconvolution analysis revealed significant modulations of the corneal immune cell profile in a time dependent manner. The results suggest that current culture conditions should be further refined and that prolonged cultivation may be detrimental. Recently, we showed that MACE enables transcriptional profiling of formalin-fixed and paraffin-embedded (FFPE) conjunctival tissue with high accuracy even after more than 10 years of storage. Here we demonstrate that MACE provides comparable results for native and FFPE corneal tissue, confirming that the technology is suitable for transcriptome analysis of a wide range of archived diseased corneal samples stored in histological archives. Finally, our data underscore the feasibility of bioinformatics cell-type enrichment analysis in bulk RNA-seq data to profile immune cell composition in fixed and archived corneal tissue samples, for which RNA-seq analysis of individual cells is often not possible.

Contact Lens-Associated Keratitis-an Often Underestimated Risk

BACKGROUND

Millions of people in Germany wear contact lenses every day. Deficient contact lens hygiene can lead to corneal infection. Contact lens-associated keratitis usually has a highly acute presentation and can cause long-term visual loss.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, as well as on relevant metaanalyses, Cochrane reviews, and reports by national and international health care authorities.

RESULTS

23-94% of contact lens wearers report associated discomfort and eye problems. The annual incidence of contact lens-associated keratitis is 2-4/10 000. It is due to bacteria in 90% of cases, and much less commonly to acanthamoebae and fungi. The pathogens generally arrive with the contact lens on the surface of the eye and can penetrate into the corneal tissue because the tear film under the lens is not swept away from the ocular surface by the eyelids, and corneal epithelial changes are often present as well. Corneal infiltration that is diagnosed early is often self-limited, but advanced bacterial infection usually requires intense topical antibiotic treatment. Some severe infections can only be eradicated by emergency corneal transplantation; this is the case in 20-30 % of fungal and acanthamoebic infections.

CONCLUSION

The wearing of contact lenses, particularly soft ones, is associated with a risk of microbial keratitis if proper contact lens hygiene is not exercised. Contact lens-associated keratitis very rarely causes permanent damage to eyesight (0.6 cases per 10 000 contact lens wearers per year). The use of contact lenses always calls for meticulous care.

Isolation and ex vivo Expansion of Limbal Mesenchymal Stromal Cells

Limbal mesenchymal stromal cells (LMSC), a cellular component of the limbal stem cell niche, have the capability of determining the fate of limbal epithelial progenitor cells (LEPC), which are responsible for the homeostasis of corneal epithelium. However, the isolation of these LMSC has proven to be difficult due to the small fraction of LMSC in the total limbal population, and primary cultures are always hampered by contamination with other cell types. We recently published the efficient isolation and functional characterization of LMSC from the human corneal limbus using CD90 as a selective marker. We observed that flow sorting yielded a pure population of LMSC with superior self-renewal capacity and transdifferentiation potential, and supported the maintenance of the LEPC phenotype. Here, we describe an optimized protocol for the isolation of LMSC from cadaveric corneal limbal tissue by combined collagenase digestion and flow sorting with expansion of LMSC on plastic. Graphical abstract.

Zur Umsetzung der Verordnung (EU) 2017/746 vom 5. April 2017 über In-vitro-Diagnostika (IVDR) in medizinischen Laboratorien, insbesondere in der Ophthalmopathologie

Die Europäische Kommission hat die Richtlinie 98/79/EG über In-vitro-Diagnostika (IVDD) überarbeitet, um die Sicherheit der Patienten zu verbessern und dem technischen Fortschritt angemessen Rechnung zu tragen. Mit der neuen Verordnung (EU) 2017/746 vom 25. Mai 2017 über In-vitro-Diagnostika (IVDR) gelten innerhalb der Europäischen Union hohe Standards für Qualität und Sicherheit von In-vitro-Diagnostika (IVD). Die IVDR richtet sich in erster Linie an Hersteller und Anbieter von IVD, hat aber auch erhebliche Auswirkungen auf medizinisch-diagnostische Labore. Ihre Anwendung ist seit dem 26. Mai 2022 verbindlich. IVD werden entsprechend ihrer Zweckbestimmung und den damit verbundenen Risiken in vier Risikoklassen A bis D eingeteilt. Erstmals werden EU-weit gesetzliche Anforderungen an Produkte aus Eigenherstellung formuliert. Jedes medizinische Labor, das „laborentwickelte Tests“ (LDT) verwendet, oder CE-IVD-Produkte verändert oder außerhalb der Herstellerangaben einsetzt, wird selbst zum Hersteller und es gilt IVDR Artikel 5 (5) in vollem Umfang. Herstellung und Verwendung von LDT müssen dann im Rahmen geeigneter QM-Systeme erfolgen. Die Gesundheitseinrichtung muss bestimmten Vorschriften (Normen) entsprechen, in Deutschland ist hier die Rili-BÄK zu nennen. LDT unterliegen den in Anhang 1 zur IVDR aufgeführten Sicherheits- und Leistungsanforderungen, darunter der Verpflichtung zur Validierung vor erstmaligem Gebrauch, während kommerzielle CE-IVD-Produkte lediglich verifiziert werden müssen. Verordnung (EU) 2022/112 vom 25. Januar 2022 sieht zwar für einige dieser Anforderungen gestaffelte Übergangsfristen von bis zu sechs Jahren vor, doch es ist zu erwarten, dass viele Labore von LDT auf kommerzielle CE-IVD-Produkte umstellen werden, weil dies letztlich ressourcenschonender für sie ist. Im vorliegenden Beitrag beschreiben wir die sich aus der IVDR ergebenden Anforderungen für medizinisch-diagnostische Labore und bieten Lösungskonzepte für deren Umsetzung in kleineren, insbesondere ophthalmopathologischen Laboratorien. The European Commission revised Directive 98/79/EC on in vitro diagnostic medical devices (IVDD) to improve patient safety and take appropriate account of technical progress. With the new Regulation (EU) 2017/746 of May 25, 2017 on in vitro diagnostic medical devices (IVDR), high standards for the quality and safety of in vitro diagnostic medical devices (IVD) apply within the European Union. The IVDR is primarily aimed at manufacturers and suppliers of IVDs, but also has significant implications for medical diagnostic laboratories. Its application is mandatory as of May 26, 2022. IVD are classified into four risk classes A to D according to their intended purpose and the associated risks. For the first time, EU-wide legal requirements are formulated for products manufactured in-house. Any medical laboratory that uses "laboratory-developed tests" (LDT), or modifies or uses CE-IVD products outside the manufacturer's specifications, becomes a manufacturer itself and IVDR Article 5 (5) applies in its entirety. Production and use of LDT must then be performed within the framework of appropriate QM systems. The health care facility must comply with certain provisions (standards), in Germany the Rili-BÄK is to be mentioned here. LDT are subject to the safety and performance requirements listed in Annex 1 to the IVDR, including the requirement for validation prior to first use, while commercial CE IVD products only require verification. Regulation (EU) 2022/112 of January 25, 2022, provides for staggered transition periods of up to six years for some of these requirements, but it is expected that many laboratories will switch from LDT to commercial CE-marked IVD products because ultimately this will be more resource-efficient for them. In this article, we describe the requirements for medical diagnostic laboratories resulting from the IVDR and offer solution concepts for their implementation in smaller, especially ophthalmopathology laboratories.