Blood-Aqueous Barrier Disruption in Penetrating and Posterior Lamellar Keratoplasty: Implications for Clinical Outcome. / Blut-Kammerwasser-Schranken-Störungen bei perforierender und posteriorer lamellärer Keratoplastik: Implikationen für das klinische Ergebnis.

BACKGROUND: The blood-aqueous barrier (BAB) separates immunoprivileged tissue of the eye from the blood circulation. Disruption of the BAB is therefore a risk factor for rejection after keratoplasty. PURPOSE: The present work provides a review of the work of our group and others on BAB disruption in penetrating and posterior lamellar keratoplasty and its implications for clinical outcome. METHODS: A PubMed literature search was performed to generate a review paper. RESULTS: Laser flare photometry provides an objective and reproducible method to assess the integrity of the BAB. Studies of the flare after penetrating and posterior lamellar keratoplasty demonstrate a mostly regressive disruption of the BAB in the postoperative course, which is influenced in extent and duration by multiple factors. Persistently elevated flare values or an increase in flare after initial postoperative regeneration may indicate an increased risk of rejection. DISCUSSION: In case of persistent or recurrent elevated flare values after keratoplasty, intensified (local) immunosuppression may potentially be useful. This could become important in the future, especially for the monitoring of patients after high-risk keratoplasty. Whether an increase of the laser flare is a reliable early indicator of an impending immune reaction after penetrating or posterior lamellar keratoplasty has to be shown in prospective studies.

Targeted Medical History and Diagnostic Testing in Uveitis. / Zielgerichtete Anamnese und Diagnostik bei Uveitis.

Uveitis is a collective term for a variety of different intraocular inflammations. The underlying etiologies vary greatly depending on the uveitis subtype, and in particular the anatomical focus. The most common forms of anterior uveitis are acute fibrinous unilateral uveitis, often associated with the HLA-B27 haplotype, and granulomatous inflammation, typically associated with sarcoidosis or herpes infections. Intermediate uveitis is usually idiopathic in nature but can also be associated with multiple sclerosis or sarcoidosis, while vitreoretinal lymphoma must also be considered as a masquerade syndrome in patients aged over 45. Posterior uveitis, on the other hand, as well as retinal vasculitis and panuveitis, have a very broad variety of etiologies; these can, however, be narrowed down through a similar findings-centered approach. Retinitis, for example, is often associated with infections (Toxoplasma gondii and viruses of the herpes group), whereas chorioditis is frequently idiopathic, although infections such as tuberculosis may occur. Therefore, the medical history and laboratory diagnosis should be tailored in patients with uveitis based on the anatomic focus of inflammation (anterior, intermediate, or posterior uveitis, or panuveitis) and the clinical picture (e.g., granulomatous versus nongranulomatous).

No secret hiding place? Absence of SARS-CoV-2 on the ocular surface of 1145 hospitalized patients in a pandemic area.

OBJECTIVES: The aims of this study were to evaluate the isolated prevalence of real-time reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 on the ocular surface without systemic infection in hospitalized asymptomatic patients and to determine the risk for ophthalmologists and medical staff to be infected by prescreened asymptomatic patients in a tertiary eye care center. METHODS: In this prospective, observational study, bilateral swaps of the conjunctiva in the lower fornices as well as nasopharyngeal swaps were collected in 1145 hospitalized asymptomatic patients of a tertiary eye care center. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed for each swap to evaluate the prevalence of SARS-CoV-2. Demographic data and potential risk factors for an isolated infection of the ocular surface were noted. RESULTS: Two thousand two hundred eighty-eight (99.9%) of all 2290 tested eyes had negative results in the RT-PCR analysis of the conjunctival swabs. One patient had bilateral false-positive results in the conjunctival swabs. None of the 1145 patients had any positive RT-PCR-confirmed result in the nasopharyngeal swabs. CONCLUSIONS: The risk for an isolated conjunctival viral activity in patients with a negative nasopharyngeal swab-based RT-PCR seems to be absent or extremely low, suggesting no need to perform additional conjunctival swabs in patients with negative nasopharyngeal swabs. Furthermore, the risk of a work-related SARS-CoV-2 infection due to direct contact with preselected asymptomatic patients in an eye care center is very low, especially when additional hygiene standards and safe distances are respected carefully. This might reassure medical staff and reduce the fear of SARS-CoV-2 infection.

Ocular Involvement in COVID-19: Conjunctivitis and More. / Okuläre Mitbeteiligung bei COVID-19: Konjunktivitis und mehr.

Since the beginning of 2020, SARS-CoV-2, the pathogen of COVID-19, has led to a global pandemic that also affects ophthalmology. Ophthalmologists can be confronted at any time with potentially COVID-19 associated ocular symptoms or manifestations in patients and also become infected through close patient contact. Even without systemic infection, the ocular surface can come into direct contact with aerosols or liquids containing SARS-CoV-2 particles. A smear infection through hand-to-eye contact is also possible. A purely isolated ocular infection has not yet been shown. Rather, it seems that ocular complications occur in the context of a systemic infection. However, ocular symptoms can also be the first symptom of COVID-19. The most common ocular complication of COVID-19 is mild follicular conjunctivitis. Haemorrhagic conjunctivitis, dry eye disease, episcleritis, or retinal involvement can also occur less frequently. There are currently no evidence-based therapy recommendations for COVID-19 associated diseases of the ocular surface. Artificial tears might be helpful for symptom relief. There is no evidence for antiviral, antibiotic, or anti-inflammatory therapies, but these medications might be used in individual cases. Potential intraocular complications include retinal artery occlusions and haemorrhages, as well as cotton wool spots caused by complement-mediated thrombotic angiopathy. Neuro-ophthalmological complications including Miller-Fisher syndrome or infarct-related central blindness can also occur in very rare cases. Knowledge of potential transmission routes and personal protective equipment is just as essential for each ophthalmologist as a basic knowledge of potential ocular symptoms and complications.

[Macular Oedema in Uveitis: Pathogenesis, Diagnosis, and Treatment]. / Makulaödem bei Uveitis: Pathogenese, Diagnostik und Therapie.

Macular oedema is the most common cause of irreversible visual loss in patients with uveitis. The pathogenesis is caused by pro-inflammatory cytokines that lead to the breakdown of the blood-retina barrier. For the diagnosis of inflammatory macular oedema, optical coherence tomography is now mainly used, but cannot always replace fluorescein angiography. The therapy is mainly performed with intravitreally applied corticosteroids as well as systemic immunomodulators and should start as early as possible to prevent chronification of macular oedema.

Impact of allergy and atopy on the risk of pseudophakic cystoid macular edema.

PURPOSE: To assess the risk of pseudophakic cystoid macular edema (PCME) following cataract surgery in patients with allergies and/or atopic disorders. PATIENTS AND METHODS: Medical records of 3,850 consecutive eyes that underwent cataract surgery were retrospectively reviewed for prevalence of allergies and atopic status and development of PCME. Patients with any known risk factors for PCME were excluded. Macular examination was performed using spectral-domain optical coherence tomography (SD-OCT) before and at 4, 8, 12, 16, 24, and 36 weeks after surgery. If both eyes in one patient underwent cataract surgery, one eye was randomly selected. Odds ratios and confidence intervals were estimated. RESULTS: Out of 240 patients enrolled in this series, 65 patients (27.1 %) showed positive allergic status, 19 patients (7.9 %) suffered from atopic syndromes, and 11 (4.6 %) showed both (allergies and atopic diseases). PCME occurred in eight patients (12.3 %) of the allergy cohort, whereas no patient (0 %) of the atopy cohort developed PCME. The risk of PCME was comparable in patients with allergies or atopic diseases to patients without allergies or atopy (allergy: p = 0.635; odds ratio (OR) 1.303, 95 % confidence interval (CI) 0.461-3.398; atopy: p = 0.234; OR 0.000, 95 % CI 0-1.815). CONCLUSION: Positive status of allergy or atopy does not seem to increase the risk of PCME. Therefore, postoperative treatment after cataract surgery does not have to be modified in allergic or atopic patients.

Ocular diseases in metastatic cutaneous melanoma: review of 108 consecutive patients in two German tertiary centers.

PURPOSE: To analyze the incidence and spectrum of ocular disease in patients with metastatic cutaneous melanoma. METHODS: One hundred and eight consecutive patients with metastatic cutaneous melanoma were screened for ocular diseases using standardized eye examination, including measurement of visual acuity and intraocular pressure, slit-lamp examination, funduscopy in mydriasis, and spectral-domain optical coherence tomography (SDOCT) of the retina. Selected cases with atypical findings underwent electrophysiological studies. One patient was examined for hypercortisolism by a dexamethasone suppression test. RESULTS: Ocular diseases were found in 65 out of 108 patients (60 %) with metastatic cutaneous melanoma, significantly more often in older patients (p = 0.004). Cataract was present in 27 patients (25 %), pseudophakia in 22 patients (20 %), macular disease in 29 patients (28 %), diabetic retinopathy in ten patients (9 %), hypertensive retinal disease in 14 patients (13 %), retinal venous and arterial occlusive disease in three patients (3 %), optic neuropathy in four patients (4 %), and uveitis in one patient (1 %). Eight patients (8 %) had choroidal or iridal nevi, one patient (1 %) choroidal hemangioma, and one patient (1 %) choroidal metastasis. No patient had periocular neoplastic lesions. Paraneoplastic retinopathy manifesting as acute exudative polymorphous vitelliform maculopathy (AEPVM)-like disease was diagnosed in two patients (2 %) with multifocal central serous chorioretinopathy and development of vitelliform or fibrin-like subretinal deposits in one patient. CONCLUSIONS: Patients with metastatic cutaneous melanoma reveal ocular diseases with a spectrum similar to the normal population of this age range. Very rarely, uveal metastasis as well as paraneoplastic retinopathy can occur.

Short- and long-term corneal vascular effects of tafluprost eye drops.

BACKGROUND: Prostaglandin analogs are first line therapy in the treatment of glaucoma, but also display side effects during ocular inflammation. In this context, the potential side effects of prostaglandin analogs on the normally avascular cornea, the main application route for eye drops, are so far not fully defined. Therefore, the aim of this study was to evaluate the vascular effects of the prostaglandin analog tafluprost on the healthy and inflamed cornea. METHODS: For in vitro studies, blood and lymphatic endothelial cells were treated with tafluprost; cell proliferation was assessed after 48 h. For long-term in vivo studies under healthy conditions, naïve corneas of BALB/c mice were treated with tafluprost eye drops for 4 weeks. For short-term in vivo studies under inflammatory conditions, corneal inflammation was induced by suture placement; mice then received tafluprost eye drops for 1 week. Afterwards, corneas were stained with CD31 as panendothelial and LYVE-1 as lymphendothelial (and macrophage) marker. RESULTS: In vitro, tafluprost did not alter blood or lymphatic endothelial cell proliferation. In vivo, there was no change in limbal blood or lymphatic vessel anatomy after long-term treatment with tafluprost. Short-term treatment with tafluprost under inflammatory conditions did not influence the recruitment of LYVE-1 positive macrophages into the cornea. Moreover, treatment of inflamed corneas with tafluprost did not significantly influence corneal hem- and lymphangiogenesis. CONCLUSIONS: Tafluprost does not affect blood and lymphatic vessel growth, neither under resting nor under inflammatory conditions. These findings suggest a safe vascular profile of tafluprost eye drops at the inflammatory neovascularized cornea.

Endogenous IRBP can be dispensable for generation of natural CD4+CD25+ regulatory T cells that protect from IRBP-induced retinal autoimmunity.

Susceptibility to experimental autoimmune uveitis (EAU), a model for human uveitis induced in mice with the retinal antigen interphotoreceptor retinoid-binding protein (IRBP), is controlled by "natural" CD4+CD25+ regulatory T (T reg) cells. To examine whether endogenous expression of IRBP is necessary to generate these T reg cells, we studied responses of IRBP knockout (KO) versus wild-type (WT) mice. Unexpectedly, not only WT but also IRBP KO mice immunized with a uveitogenic regimen of IRBP in complete Freund's adjuvant (CFA) exhibited CD25+ regulatory cells that could be depleted by PC61 treatment, which suppressed development of uveitogenic effector T cells and decreased immunological responses to IRBP. These EAU-relevant T reg cells were not IRBP specific, as their activity was not present in IRBP KO mice immunized with IRBP in incomplete Freund's adjuvant (IFA), lacking mycobacteria (whereas the same mice exhibited normal T reg cell activity to retinal arrestin in IFA). We propose that mycobacterial components in CFA activate T reg cells of other specificities to inhibit generation of IRBP-specific effector T cells in a bystander fashion, indicating that effective T reg cells can be antigen nonspecific. Our data also provide the first evidence that generation of specific T reg cells to a native autoantigen in a mouse with a diverse T cell repertoire requires a cognate interaction.

Intravitreal treatment with antisense oligonucleotides targeting tumor necrosis factor-α in murine herpes simplex virus type 1 retinitis.

BACKGROUND: Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine known to participate in intraocular inflammatory disease. This study investigated whether treatment with intravitreal antisense-oligonucleotides (ASON) targeting TNF-α mRNA affects the progression of herpes simplex virus 1 (HSV-1) retinitis in mice. METHODS: The in vivo uptake of the oligonucleotid after intravitreal injection was determined with FITC-labeled TNF-α ASON. HSV-retinitis was induced on day 0 by the injection of HSV-1 (KOS strain) into the anterior chamber (AC) of the right eyes of BALB/c mice (von Szily model). The left contralateral eyes were injected intravitreally on day 7 with TNF-α ASON, sequence-unspecific control ASON (CON), or buffer. The clinical course of retinitis, ocular inflammatory cell-infiltration, TNF-α expression in the eye by ELISA, delayed-type hypersensitivity (DTH) reaction, virus-neutralizing antibody titers in the serum, uptake of [3H]thymidine from regional lymph node (rln) cells, and viral content in the eyes were determined. RESULTS: In vivo, strong fluorescence of FITC- TNF-α ASON was detected in the choroid and retina up to 3 days after intravitreal injection, but none in the rln. After treatment of eyes with ASON, decreased expression of TNF-α in the eye, and reduced incidence and severity of retinitis on day 10 after infection (P < 0.05) could be found. The other parameters were not significantly influenced after TNF-α ASON treatment. CONCLUSIONS: TNF-α participates in the pathology of HSV-1 retinitis. Local inhibition of TNF-α mRNA by intraocular TNF-α ASON injection did not influence the systemic HSV-specific immune response or the antiviral response in the eye, but reduced ocular inflammatory bystander damage.

Calcitriol suppresses antiretinal autoimmunity through inhibitory effects on the Th17 effector response.

Experimental autoimmune uveitis (EAU) serves as a model for human autoimmune uveitis and for cell-mediated autoimmunity in general. EAU induced in mice by immunization with the retinal Ag interphotoreceptor retinoid-binding protein in CFA is driven by the Th17 response. Oral calcitriol (1,25-dihydroxyvitamin D(3)) prevented as well as partly reversed disease and suppressed immunological responses. In vitro, calcitriol directly suppressed IL-17 induction in purified naive CD4(+) T cells without inhibiting Th17 lineage commitment, as reflected by unaltered RORgammat, STAT3, and FoxP3 expression. In contrast, in vivo treatment with calcitriol of mice challenged for EAU impaired commitment to the Th17 lineage, as judged by reduction of both RORgammat and IL-17 in CD4(+) T cells. Innate immune response parameters in draining lymph nodes of treated mice were suppressed, as was production of IL-1, IL-6, TNF-alpha, and IL-12/IL-23p40, but not IL-10, by explanted splenic dendritic cells (DC). Finally, supernatants of calcitriol-conditioned bone marrow-derived DC had reduced ability to support Th17 polarization of naive CD4(+) T cells in vitro and in vivo. Thus, calcitriol appears to suppress autoimmunity by inhibiting the Th17 response at several levels, including the ability of DC to support priming of Th17 cells, the ability of CD4(+) T cells to commit to the Th17 lineage, and the ability of committed Th17 T cells to produce IL-17.

An immunologically privileged retinal antigen elicits tolerance: major role for central selection mechanisms.

Immunologically privileged retinal antigens can serve as targets of experimental autoimmune uveitis (EAU), a model for human uveitis. The tolerance status of susceptible strains, whose target antigen is not expressed in the thymus at detectable levels, is unclear. Here, we address this issue directly by analyzing the consequences of genetic deficiency versus sufficiency of a uveitogenic retinal antigen, interphotoreceptor retinoid-binding protein (IRBP). IRBP-knockout (KO) and wild-type (WT) mice on a highly EAU-susceptible background were challenged with IRBP. The KO mice had greatly elevated responses to IRBP, an altered recognition of IRBP epitopes, and their primed T cells induced exacerbated disease in WT recipients. Ultrasensitive immunohistochemical staining visualized sparse IRBP-positive cells, undetectable by conventional assays, in thymi of WT (but not of KO) mice. IRBP message was PCR amplified from these cells after microdissection. Thymus transplantation between KO and WT hosts demonstrated that this level of expression is functionally relevant and sets the threshold of immune (and autoimmune) reactivity. Namely, KO recipients of WT thymi generated reduced IRBP-specific responses, and WT recipients of KO thymi developed enhanced responses and a highly exacerbated disease. Repertoire culling and thymus-dependent CD25+ T cells were implicated in this effect. Thus, uveitis-susceptible individuals display a detectable and functionally significant tolerance to their target antigen, in which central mechanisms play a prominent role.

Activation of invariant NKT cells ameliorates experimental ocular autoimmunity by a mechanism involving innate IFN-gamma production and dampening of the adaptive Th1 and Th17 responses.

Invariant NKT cells (iNKT cells) have been reported to play a role not only in innate immunity but also to regulate several models of autoimmunity. Furthermore, iNKT cells are necessary for the generation of the prototypic eye-related immune regulatory phenomenon, anterior chamber associated immune deviation (ACAID). In this study, we explore the role of iNKT cells in regulation of autoimmunity to retina, using a model of experimental autoimmune uveitis (EAU) in mice immunized with a uveitogenic regimen of the retinal Ag, interphotoreceptor retinoid-binding protein. Natural strain-specific variation in iNKT number or induced genetic deficiencies in iNKT did not alter baseline susceptibility to EAU. However, iNKT function seemed to correlate with susceptibility and its pharmacological enhancement in vivo by treatment with iNKT TCR ligands at the time of uveitogenic immunization reproducibly ameliorated disease scores. Use of different iNKT TCR ligands revealed dependence on the elicited cytokine profile. Surprisingly, superior protection against EAU was achieved with alpha-C-GalCer, which induces a strong IFN-gamma but only a weak IL-4 production by iNKT cells, in contrast to the ligands alpha-GalCer (both IFN-gamma and IL-4) and OCH (primarily IL-4). The protective effect of alpha-C-GalCer was associated with a reduction of adaptive Ag-specific IFN-gamma and IL-17 production and was negated by systemic neutralization of IFN-gamma. These data suggest that pharmacological activation of iNKT cells protects from EAU at least in part by a mechanism involving innate production of IFN-gamma and a consequent dampening of the Th1 as well as the Th17 effector responses.

Anti-inflammatory treatment of uveitis with biologicals: new treatment options that reflect pathogenetic knowledge of the disease.

BACKGROUND: Endogenous uveitis is a sight-threatening disease. In addition to corticosteroids, immunosuppressive agents are commonly used to treat patients with severe course. Immunosuppressive drugs act nonspecifically, rather than providing a specific interaction with the critical pathogenetic pathways of uveitis. Better knowledge of the basic mechanisms underlying uveitis and of the molecules that are important for regulating inflammation has helped to create new and more specific treatment approaches. Biological therapy for inflammatory diseases employs substances that interfere with specific molecules or pathways induced in the body during the inflammatory process. METHODS: This review gives an overview on molecules that play a critical role in the pathogenetic process of uveitis, as has been observed in patients or the respective animal models, and summarizes the current experience with biologicals for the treatment of uveitis refractive to conventional immunosuppressives.

[The role of ophthalmology in the COVID-19 pandemic]. / Die Rolle der Augenheilkunde in der COVID-19-Pandemie.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 19 (COVID-19) has led to a worldwide pandemic. This pandemic presents a huge challenge for the healthcare system and also for ophthalmologists. Previous studies and case reports indicated that SARS-CoV­2 also infects the conjunctiva resulting in conjunctivitis. In addition, infectious virus particles in the tear fluid can be potential sources of infection; however, the detection of SARS-CoV­2 RNA in the tear fluid has rarely been successful. Although isolated conjunctival involvement is highly unlikely, at the current point in time of the COVID-19 pandemic, practically every patient examined by an ophthalmologist could be infected with SARS-CoV­2. Therefore, protective and hygiene measures should currently be consistently followed to minimize the risk of spreading the virus. Currently, there are no treatment recommendations for conjunctivitis associated with COVID-19. Tear substitutes might be helpful for symptom relief but there is no evidence for a topical antiviral therapy. In the future ophthalmologists could play a decisive role in the screening of maculopathies that might occur during COVID-19 treatment using chloroquine or hydroxychloroquine.

More than loss of taste and smell: burning watering eyes in coronavirus disease 2019.

OBJECTIVES: To evaluate ocular symptoms in European non-hospitalized patients with severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and to investigate associations with the demographic data as well as nasal and general physical symptoms. METHODS: In this prospective, observational study, 108 non-hospitalized patients with PCR-confirmed SARS-CoV-2 infection not requiring intensive care were asked about disease-associated ocular symptoms, demographic data, as well as general physical and nasal symptoms using a standardized questionnaire. Total ocular symptom score (TOSS) was evaluated during and, retrospectively, before development of coronavirus disease 2019 (COVID-19). Associations between TOSS and demographic data as well as general and nasal symptoms were evaluated. RESULTS: Seventy-five of the 108 COVID-19 patients (69.4%) had at least one ocular symptom during COVID-19. The most common symptoms included burning sensations in 39 (36.1%), epiphora in 37 (34.3%) and redness in 28 (25.9%), compatible with conjunctivitis. These symptoms occurred 1.96 ± 3.17 days after the beginning of COVID-19 and were mild. TOSS was significantly higher during COVID-19 (1.27 ± 1.85) than before the infection (0.33 ± 1.04; p < 0.001). There were no significant associations between TOSS and gender (ß coefficient -0.108; p 0.302), age (-0.024; p 0.816), rhinorrhoea (-0.127; p 0.353), nasal itching (-0.026; p 0.803), sneezing (0.099; p 0.470), nasal congestion (-0.012; p 0.930), cough (-0.079; p 0.450), headache (0.102; p 0.325), sore throat (0.208; p 0.052), or fever (0.094; p 0.361). CONCLUSIONS: Ocular involvement in European non-hospitalized individuals with COVID-19 seems to be highly underestimated. Overall, these ocular symptoms, including burning sensations, epiphora and redness, seem to be mild and to not need treatment.

Perceived Stress Levels in Adult Patients With Uveitis.

Background: The aim of this study was to examine perceived stress levels in adult patients with uveitis. Patients and Methods: One hundred seventy-three adult consecutive uveitis patients (age range 18 to 85 years) were analyzed in a cross-sectional design for their perceived stress, according to the Perceived Stress Questionnaire (PSQ). Stress levels were classified into normal stress, moderate stress, and high stress. Results: In the majority of uveitis patients a normal stress level (82%) within the last 2 years was detected. In a subgroup analysis, perceived stress of the patients with active uveitis compared with patients with non-active uveitis was significantly higher within the last 2 years (n=80 active/n = 45 non-active; p = 0.005). Conclusions: Overall 18% of the uveitis patient had raised perceived stress, similar to the general population but patients with active uveitis were significantly more stressed. Therefore, consideration of stress levels may be important in the therapy of uveitis patients.