Severe Complications after Corneal Collagen Cross-Linking (CXL)

Purpose To present a case series of rare and severe complications after corneal collagen cross-linking (CXL) of keratoconus patients. Methods Single-center descriptive case series covering the period of 2012 to 2022 at the Department of Ophthalmology at the University Hospital, Zurich, Switzerland. Results We present four eyes of four patients that showed severe unusual complications within the first month after CXL. Three patients had been treated with the classical epithelium-off “Dresden” protocol. One patient had been treated with the accelerated epithelium-off protocol. One patient presented with extensive corneal edema due to rubbing the eye after treatment. Two patients showed a bacterial infectious keratitis: one due to Streptococcus pneumoniae and the other due to Staphylococcus hominis, Micrococcus luteus, and Streptococcus epidermidis. The latter of the two patients exhibited extensive infectious crystalline keratopathy. The fourth patient showed a severe ulcerative lesion where no infectious cause could be found. Therefore, an autoimmune keratolytic process had to be suspected. Apart from the corneal edema, which resolved ad integrum, the other complications resulted in permanent corneal scarring and thinning. One patient needed an emergency amniotic transplant. Conclusion Severe complications after CXL remain rare. Most common causes are complications that are not directly associated with the treatment as such. Those indirect complications occur after the treatment during the healing course of the epithelium. Associations with bandage contact lenses, topical steroids, atopic disease, and inappropriate patient behavior are often suspected. Correctly performed corneal scrapings with repeated microbiological analysis and a detailed patient history are essential for establishing the correct diagnosis, especially in complicated cases that do not respond to a standard therapeutic regimen. This case series supports the efforts that are currently taken to improve the CXL technique in a way that postoperative complications are further reduced. A more efficient epithelium-on technique might be a step in that direction. // Ziel Darstellung einer Fallserie von seltenen, schwerwiegenden Komplikationen nach kornealem Kollagen-Crosslinking (CXL) von Patienten mit Keratokonus. Methoden Monozentrische, beschreibende Fallserie über einen Zeitraum von 2012 bis 2022 an der Augenklinik des Universitätsspitals Zürich, Schweiz. Ergebnisse Wir zeigen 4 Augen von 4 Patienten, die mit ungewöhnlichen, schwerwiegenden Komplikationen innerhalb des 1. Monats nach CXL an unserer Klinik vorstellten. Drei der Patienten waren mit dem klassischen Epithelium-off-„Dresden“-Protokoll behandelt worden, ein Patient mit einem beschleunigten Epithelium-off-Protokoll. Ein Patient stellte sich mit einem ausgeprägten Hornhautstromaödem aufgrund von Reiben des Auges vor. Zwei Patienten zeigten eine infektiöse, bakterielle Keratitis mit Streptococcus pneumoniae bzw. Staphylococcus hominis, Micrococcus luteus, Streptococcus epidermidis. Der 4. Patient zeigte eine schwere ulzerative Läsion ohne nachweisbare infektiöse Genese, weshalb ein autoimmuner, keratolytischer Prozess vermutet wurde. Außer dem Hornhautödem, das sich vollständig zurückbildete, resultierten die anderen Komplikationen in einer bleibenden Vernarbung und Ausdünnung der Hornhaut. Ein Patient benötigte eine notfallmäßige Amnionmembrantransplantation. Schlussfolgerung Schwerwiegende Komplikationen nach CXL bleiben selten. Die häufigsten Ursachen hierfür sind Komplikationen, die nicht direkt mit der eigentlichen Prozedur zusammenhängen, sondern erst im postoperativen Heilungsverlauf des Hornhautepithels auftreten. Ein Zusammenhang mit therapeutischen Kontaktlinsen und unangemessenem Patientenverhalten wird in vielen Fällen angenommen. Korrekt durchgeführte Hornhaut-Scrapings mit wiederholter mikrobiologischer Aufarbeitung und eine detaillierte Patientenanamnese sind unerlässlich für eine korrekte Diagnosestellung, insbesondere in komplizierten Fällen, die nicht auf die üblichen Therapieregime ansprechen. Diese Fallserie unterstützt die aktuellen Bemühungen, die CXL-Technik dahingehend zu verbessern, sodass postoperative Komplikationen weiter reduziert werden. Eine effizientere Epithelium-on-Technik wäre ein Schritt in diese Richtung

Correlation between Macular Neovascularization (MNV) Type and Druse Type in Neovascular Age-Related Macular Degeneration (AMD) Based on the CONAN Classification

To investigate associations and predictive factors between macular neovascularization (MNV) lesion variants and drusen types in patients with treatment-naïve neovascular age-related macular degeneration (AMD). Methods: Multimodal imaging was retrospectively reviewed for druse type (soft drusen, subretinal drusenoid deposits (SDDs) or mixed) and MNV type (MNV 1, MNV 2, MNV 1/2 or MNV 3). The Consensus on Neovascular AMD Nomenclature (CONAN) classification was used for characterizing MNV at baseline. Results: One eye of each eligible patient was included (n = 191). Patients with predominant SDDs had an increased adjusted odds ratio (aOR) for MNV 2 (23.4453, p = 0.0025) and any type of MNV 3 (8.7374, p < 0.0001). Patients with MNV 1/2 had an aOR for predominant SDDs (0.3284, p = 0.0084). Patients with MNV1 showed an aOR for SDDs (0.0357, p < 0.0001). Eyes with SDDs only without other drusen types showed an aOR for MNV 2 (9.2945, p < 0.0001). Conclusions: SDDs represent a common phenotypic characteristic in AMD eyes with treatment-naïve MNV. The aOR for eyes with predominant SDDs to develop MNV 2 and MNV 3 was much higher, possibly due to their location in the subretinal space. The predominant druse type may help to predict which type of MNV will develop during the course of AMD

Analysis of Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) Parameters in Young Adults after SARS-CoV-2 Infection (COVID-19) Compared with Healthy Young Controls

Purpose: To compare retinal changes in young adults with previous SARS-CoV-2 infection with healthy young controls using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Methods: This prospective single-center study was conducted at the University Hospital of Zurich, Zurich, Switzerland. Participants were imaged from May to November 2021 using the SOLIX device (Visionix International SAS, Pont-de-l’Arche, France). We performed 12 mm × 12 mm, 6.4 mm × 6.4 mm, 6 mm × 6 mm and 3 mm × 3 mm OCT and OCTA scans, as well as fundus photography of each participant’s eyes. Results: In total, 466 participants were imaged. Of these, 233 were healthy controls with negative RT-PCR tests for SARS-CoV-2, 168 were young adults who had a SARS-CoV-2 infection at least 180 days previously, 19 were participants who had a SARS-CoV-2 infection < 180 days previously, and 46 were participants with asymptomatic SARS-CoV-2 infection (i.e., serologically positive but with no symptoms). Compared with healthy controls, statistically significant differences were found for OCTA recordings of the optic disc for the whole image (WI) and WI capillary vessel density, with both being higher in the SARS-CoV-2 group. Conclusion: Statistically significant results were only observed for selected variables, and in parts, only unilaterally, with relatively large p values (p = 0.02–0.03). Thus, we did not interpret these as clinically significant, leading to the conclusion that young and otherwise healthy individuals (mainly men) seem to recover from mild COVID-19 infections with no ophthalmological residues

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Smartphone Slit Lamp Imaging—Usability and Quality Assessment

Purpose: To assess the usability and image quality of a smartphone adapter for direct slit lamp imaging. Methods: A single-center, prospective, clinical study conducted in the Department of Ophthalmology at the University Hospital Zurich, Switzerland. The smartphone group consisted of 26 medical staff (consultants, residents, and students). The control group consisted of one ophthalmic photographer. Both groups took images of the anterior and the posterior eye segment of the same proband. The control group used professional photography equipment. The participant group used an Apple iPhone 11 mounted on a slit lamp via a removable SlitREC smartphone adapter (Custom Surgical GmbH, Munich, Germany). The image quality was graded independently by two blinded ophthalmologists on a scale from 0 (low) to 10 (high quality). Images with a score ≥ 7.0/10 were considered as good as the reference images. The acquisition time was measured. A questionnaire on usability and experience in smartphone and slit lamp use was taken by all of the participants. Results: Each participant had three attempts at the same task. The overall smartphone quality was 7.2/10 for the anterior and 6.4/10 for the posterior segment. The subjectively perceived difficulty decreased significantly over the course of three attempts (Kendall’s W). Image quality increased as well but did not improve significantly from take 1 to take 3. However, the image quality of the posterior segment was significantly, positively correlated (Spearman’s Rho) with work experience. The mean acquisition time for anterior segment imaging was faster in the smartphone group compared to the control group (156 vs. 206 s). It was vice versa for the posterior segment (180 vs. 151 s). Conclusion: Slit lamp imaging with the presented smartphone adapter provides high-quality imaging of the anterior segment. Posterior segment imaging remains challenging in terms of image quality. The adapter constitutes a cost-effective, portable, easy-to-use solution for recording ophthalmic photos and videos. It can facilitate clinical documentation and communication among colleagues and with the patient especially outside normal consultation hours. Direct slit lamp imaging allows for time to be saved and increases the independence of ophthalmologists in terms of patient mobility and the availability of photographic staff

No Pain, No Gain – Topical Anesthesia-Induced Keratopathy

Topical anesthesia is an indispensable element of modern ophthalmic practice, most valuable during minor procedures and ocular examinations. However, regularly applied and prolonged use of local anesthetics may cause significant ocular damage. The spectrum of adverse effects is heterogeneous, ranging from mild conjunctival injection with superficial punctate keratopathy to persistent corneal epithelial defects, endothelial decompensation, ulcer formation, secondary infectious keratitis, and possible corneal perforation [1], [2]. Hence, timely identification of the underlying cause is essential to initiate targeted therapeutic measures. However, as topical anesthesia-induced keratopathy is a rare entity in Switzerland and its clinical picture may resemble infectious keratitis [3], the ophthalmologistʼs initial diagnosis poses a challenging task. This case report aims to further raise awareness about topical anesthetic abuse keratopathy

Smartphone Slit Lamp Imaging&mdash;Usability and Quality Assessment

Purpose: To assess the usability and image quality of a smartphone adapter for direct slit lamp imaging. Methods: A single-center, prospective, clinical study conducted in the Department of Ophthalmology at the University Hospital Zurich, Switzerland. The smartphone group consisted of 26 medical staff (consultants, residents, and students). The control group consisted of one ophthalmic photographer. Both groups took images of the anterior and the posterior eye segment of the same proband. The control group used professional photography equipment. The participant group used an Apple iPhone 11 mounted on a slit lamp via a removable SlitREC smartphone adapter (Custom Surgical GmbH, Munich, Germany). The image quality was graded independently by two blinded ophthalmologists on a scale from 0 (low) to 10 (high quality). Images with a score &ge; 7.0/10 were considered as good as the reference images. The acquisition time was measured. A questionnaire on usability and experience in smartphone and slit lamp use was taken by all of the participants. Results: Each participant had three attempts at the same task. The overall smartphone quality was 7.2/10 for the anterior and 6.4/10 for the posterior segment. The subjectively perceived difficulty decreased significantly over the course of three attempts (Kendall&rsquo;s W). Image quality increased as well but did not improve significantly from take 1 to take 3. However, the image quality of the posterior segment was significantly, positively correlated (Spearman&rsquo;s Rho) with work experience. The mean acquisition time for anterior segment imaging was faster in the smartphone group compared to the control group (156 vs. 206 s). It was vice versa for the posterior segment (180 vs. 151 s). Conclusion: Slit lamp imaging with the presented smartphone adapter provides high-quality imaging of the anterior segment. Posterior segment imaging remains challenging in terms of image quality. The adapter constitutes a cost-effective, portable, easy-to-use solution for recording ophthalmic photos and videos. It can facilitate clinical documentation and communication among colleagues and with the patient especially outside normal consultation hours. Direct slit lamp imaging allows for time to be saved and increases the independence of ophthalmologists in terms of patient mobility and the availability of photographic staff

Analysis of opacification patterns in intraocular lenses (IOL)

Objective Intraocular lens (IOL) opacification may cause severe visual impairment. The pathogenesis remains unclear. The aim of this study was to analyse opacification patterns in different IOLs. Therefore, this multicentre, retrospective, observational study was conducted at Ludwig-Maximilians-University, Munich, Germany and University-Hospital Basel, Switzerland.Methods and analysis In this study, 75 opacified IOLs were identified and classified after extraction. Macroscopical photo documentation, light and electron microscopic analysis were done.Results 68 acrylic-hydrophilic single-piece-IOLs, 1 acrylic-hydrophilic 3-piece-IOL, 6 acrylic-hydrophobic 3-piece-IOLs were extracted. The dataset comprised IOLs known for opacification and IOLs not having been reported yet. 67 IOLs showed a fine-granular and 8 IOLs a crust-like opacification pattern. According to literature, 62 of the fine-granular opacified IOLs were graded into type 1 (processing/packaging-induced primary opacification) and 13 into type 2 (secondary opacification of unknown aetiology). The anterior surface of the IOLs was affected in all 75 IOLs, the posterior surface only in 23 cases. Of all 67 fine-granular IOLs, 43 had a central defect and 21 had a zone without opacification (clear islet).Conclusion In our series, the morphology of IOL opacification did not follow the existing pathogenetic classification that strictly discriminates between primary and secondary causes. Fine-granular IOL opacification occurs with similar patterns in both type 1 and type 2 IOL opacification, while a crust-like pattern was only detected in type 2 IOL opacifications. Consequently, susceptibility of an IOL to opacification is caused by a multifactorial combination of material and processing properties as well as individual (pathological) conditions of the patient

Microsporidial Stromal Keratitis: A Rare Entity in Central Europe

Recent data analyses account for corneal opacities as the fifth leading cause of blindness worldwide [1], with infectious keratitis being the most common condition [2], [3]. Microsporidia are obligate intracellular, spore-forming fungi that may cause such infectious keratitis. Their ubiquitous presence in the environment leads to frequent human exposure [4], although the exact pathogenesis of keratitis remains unclear. Direct inoculation with contaminated water, food, soil, and ocular trauma has been postulated [5], [6]. There are two different corneal manifestations of microsporidial keratitis: multifocal epithelial keratitis, which mainly affects immunosuppressed patients as in human immunodeficiency virus (HIV), and stromal keratitis, largely seen among immunocompetent individuals [7]. The disease entity is endemic in Asian countries and has rarely been reported in Europe [8]. We describe a case of histopathologically confirmed stromal microsporidial keratitis diagnosed at a tertiary care hospital in Switzerland

Natural Course of Solar and Laser-Associated Retinal and Macular Injuries at a Primary Care Hospital in Switzerland

Background: Solar and laser-associated retinopathies are rare occurrences. The two retinopathies are both photo-induced but differ in the involved intensity and duration of exposure. The purpose of this study was to evaluate the clinical features and natural course of these two entities, with a focus on the changes in the outer retina over time. Patients and Methods: This retrospective analysis assessed patients with solar or laser maculopathy seen at the Department of Ophthalmology of the University Hospital Zurich in Switzerland over the last 10 years. Visual acuity (VA; Snellen) and optical coherence tomography (OCT) findings were reviewed and analyzed at baseline and last follow-up visit. Areas of damaged outer retina, identified on en face OCT images as hyporeflective areas, were tagged and compared between visits. Descriptive analysis was performed by calculating mean values ± standard deviation (SD). Statistical evaluation was done using the Wilcoxon signed rank test. A p value < 0.05 was considered statistically significant. Results: Five patients with solar retinopathy and six patients with laser-associated retinopathy were identified. In the solar retinopathy group, mean VA at baseline was 0.80 (SD ± 0.37) and improved to 0.90 (SD ± 0.36). This was not statistically significant (p = 0.066). In the laser-associated retinopathy group, mean VA at baseline was 0.89 (SD ± 0.18) and improved to 1.03 (SD ± 0.09), which was not statistically significant either (p = 0.063). At baseline, in OCT cross-sections, initial changes were observed in the interdigitation, myoid, and ellipsoid zone, as well as the outer nuclear layer and the Henle fiber layer. At follow-up, most cases presented an alteration in the residual ellipsoid zone, with the degree of the aforementioned alterations depending on the size of the initial defect. A decrease of the hyporeflective alterations measured in en face OCT scans was observed in both groups but was only statistically significant in the laser-associated retinopathy group (p = 0.018 versus p = 0.172). Conclusions: OCT can help to detect and monitor solar and laser-associated retinal injuries. Most injuries are minor, with good functional restitution. Minor changes in the ellipsoid zone often persist, even in cases with full visual recovery. // Hintergrund: Solare und laserassoziierte Retinopathien sind seltene Vorkommnisse. Beide Retinopathien sind fotoinduziert, mit aber sehr unterschiedlicher Expositionsdauer und Intensität. Ziel dieser Studie ist den natürlichen Verlauf dieser zwei Krankheitsbilder zu evaluieren mit speziellem Fokus auf die Alterationen in der äußeren Netzhaut. Patienten und Methoden: Es handelt sich um eine retrospektive Studie, welche Patienten mit solarer oder laserassoziierter Retinopathie an der Augenklinik des Unversitätsspitals Zürich über die letzten zehn Jahre einschließt. Visus (Snellen) und optische Kohärenztomografie-(OCT-)Aufnahmen bei erster und letzter Konsultation wurden überprüft und analysiert. Ergebnisse: Fünf Patienten mit solarer Retinopathie und sechs Patienten mit laserassoziierter Retinopathie konnten eingeschlossen werden. Bei der Gruppe der solaren Retinopathie stieg der Visus von 0,8 (SD ± 0,37) auf 0,90 (SD ± 0,36) an. Dies war nicht statistisch signifikant (p = 0,066). Bei der Gruppe der laserassoziierten Retinopathie stieg der Visus von 0,89 (SD ± 0,18) auf 1,03 (SD ± 0,09) an, ebenfalls nicht statistisch signifikant (p = 0,063). In der OCT konnten Alterationen in der Interdigitationszone, der ellipsoiden Zone und der äußeren Körnerzellschicht/Henle-Faser-Schicht gesehen werden. Fast alle Fälle zeigten einen persistierenden Defekt in der ellipsoiden Zone und teilweise auch eine Atrophie des retinalen Pigmentepithels. Beide Gruppen zeigten eine Abnahme der Fläche des hyporeflektiven Areals auf Niveau der ellipsoiden Zone in der En-face-OCT, dies war jedoch nur bei der Gruppe der laserassoziierten Retinopathien signifikant (p = 0,018 versus p = 0,172). Schlussfolgerungen: OCT unterstützt die Diagnostik bei solarer und laserassoziierter Retinopathie, insbesondere bei sehr milden Verletzungen. Bei beiden Krankheitsbilder handelt es sich meist um geringgradige Befunde mit guter Prognose. Auch in Fällen mit kompletter visueller Erholung kann häufig noch eine kleine Alteration in der ellipsoiden Zone persistieren