IL-10 Indirectly Regulates Corneal Lymphangiogenesis and Resolution of Inflammation via Macrophages.

The role of IL-10, a primarily anti-inflammatory cytokine, in the regulation of inflammatory lymphangiogenesis is undetermined. Herein, we show that IL-10 modulates corneal lymphangiogenesis and resolution of inflammation. IL-10 was not expressed in healthy corneas but was up-regulated in inflamed corneas by infiltrating macrophages. Macrophages up-regulated the expression of prolymphangiogenic vascular endothelial growth factor-C upon stimulation with IL-10. Consistently, corneal inflammation resulted in reduced expression of vascular endothelial growth factor-C and decreased corneal lymphangiogenesis in IL-10-deficient mice (IL-10(-/-)). The effect of IL-10 on lymphangiogenesis was indirect via macrophages, because IL-10 did not directly affect lymphatic endothelial cells. The expression of proinflammatory cytokines and the numbers of infiltrating macrophages increased and remained elevated in inflamed corneas of IL-10(-/-) mice, indicating that IL-10 deficiency led to more severe and prolonged inflammation. The corneal phenotype of IL-10 deficient mice was mimicked in mice with conditional deletion of Stat3 in myeloid cells (lysozyme M Cre mice Stat3(fl/fl) mice), corroborating the critical role of macrophages in the regulation of lymphangiogenesis. Furthermore, local treatment with IL-10 promoted lymphangiogenesis and faster egress of macrophages from inflamed corneas. Taken together, we demonstrate that IL-10 indirectly regulates inflammatory corneal lymphangiogenesis via macrophages. Reduced lymphangiogenesis in IL-10(-/-) and lysozyme M Cre Stat3(fl/fl) mice is associated with more severe inflammatory responses, whereas IL-10 treatment results in faster resolution of inflammation. IL-10 might be used therapeutically to terminate pathological inflammation.

Corneal confocal microscopy detects small fiber damage in chronic inflammatory demyelinating polyneuropathy (CIDP).

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune-mediated peripheral neuropathy with multifocal involvement. Reliable biomarkers for diagnosis, disease progression, and treatment response remain to be developed. We assessed the utility of corneal confocal microscopy (CCM) as a diagnostic marker for CIDP in 16 patients. CCM parameters including corneal nerve fiber density (NFD), nerve fiber length, number of main nerve trunks, number of nerve branches, nerve tortuosity, and dendritic cell density (DCD) were compared to those from 15 healthy controls and correlated with clinical and electrophysiological findings. CIDP patients had a significantly lower corneal NFD compared to healthy controls. The total nerve fiber length and the number of nerve branches were significantly decreased, whereas nerve tortuosity was increased in patients with CIDP. There was no positive correlation between corneal NFD and clinical or electrophysiological assessments. The average DCD was not significantly different in CIDP patients and controls. CCM measures suggest damage to small sensory afferents in the cornea in CIDP patients. Further studies are needed to compare different neuropathic conditions and to explore longitudinal changes of CCM parameters.

Blockade of the VEGF isoforms in inflammatory corneal hemangiogenesis and lymphangiogenesis.

BACKGROUND: The VEGF-A family plays a crucial role in the induction of pathological corneal neovascularization. The role of the different VEGF-A isoforms during lymphangiogenesis is only little-known. Current anti-angiogenic therapies in the eye and other organs inhibit all VEGF-A isoforms, and have effects on both blood and lymphatic vessels. Here we investigate whether selective targeting of the isoform VEGF 165 is able to inhibit corneal lymphangiogenesis under inflammatory conditions. METHODS: The mouse model of suture-induced corneal neovascularization was used to assess the antihem- and antilymphangiogenic effect of topically applied pegaptanib. Corneal blood and lymph vascularized areas were analyzed morphometrically. Furthermore, we analyzed the proliferative effects of VEGF A 121, 165, and 189 on blood and lymphatic endothelial cells (BEC/LEC) via a cell-proliferation assay. RESULTS: Pegaptanib significantly inhibited inflammatory corneal hemangiogenesis (p < 0.01), but not lymphangiogenesis in vivo (p > 0.05), both topically as well as systemically, in the inflamed cornea. In vitro, BECs were more susceptible to pegaptanib than LECs. CONCLUSIONS: Targeting VEGF-A 165 significantly inhibits hem- but not lymphangiogenesis, suggesting VEGF-A 165 to be critical for hem-, but dispensable for lymphangiogenesis, at least in the inflamed cornea.

Corneal nerve alterations in different stages of Fuchs' endothelial corneal dystrophy: an in vivo confocal microscopy study.

PURPOSE: To analyze potential alterations in corneal nerve morphology and function in different stages of Fuchs' endothelial corneal dystrophy (FECD). METHODS: Thirty eyes with FECD underwent in vivo confocal microscopy using the Heidelberg Retina Tomograph II (HRT II; Heidelberg Engineering, Heidelberg, Germany) and the Rostock Cornea Module (RCM) to quantify the morphology of the central subbasal corneal nerve plexus (total nerve length, total nerve number, number of main nerve trunks, number of nerve branches) as well as esthesiometry (using the Cochet-Bonnet esthesiometer) of the central cornea to determine central corneal sensation as a measure of nerve function. Findings were correlated with an age-matched control group of 30 healthy individuals. Comparisons to biomicroscopical stage of FECD, visual acuity and central corneal thickness were performed using Spearman correlation. RESULTS: Depending on slit-lamp examination, all 30 eyes were classified into FECD stage 1-4 (stage 1: six eyes; stage 2: 15 eyes; stage 3: six eyes; stage 4: three eyes). Total nerve length (ρ = -0.8, p < 0.001), total nerve number (ρ = -0.7, p < 0.001), number of main nerve trunks (ρ = -0.6, p < 0.001), and number of nerve branches (ρ = -0.7, p < 0.001) decreased significantly with increasing FECD stages. Comparing to the visual acuity, significant positive correlations were found for total nerve length (ρ = 0.5, p = 0.012), total nerve number (ρ = 0.5, p = 0.005), number of main nerve trunks (ρ = 0.4, p = 0.017), and number of nerve branches (ρ = 0.5, p = 0.009). With central corneal thickness, there were significant inverse correlations for total nerve length (ρ = -0.6, p = 0.001), total nerve number (ρ = -0.5, p = 0.012), number of main nerve trunks (ρ = -0.4, p = 0.015), and number of nerve branches (ρ = -0.4, p = 0.017). Central corneal sensation was full in all FECD stage 1, stage 2 and stage 3 eyes, but mildly reduced in FECD stage 4 eyes. CONCLUSIONS: Increasing severity of Fuchs' endothelial corneal dystrophy (FECD) is concurrent with marked attenuation of the density, as well as mild diminishment of the function, of the subbasal corneal nerve plexus in late stage of the disease.

Split cornea transplantation: relationship between storage time of split donor tissue and outcome.

PURPOSE: To analyze the relationship between storage time of split donor tissue and outcomes after deep anterior lamellar keratoplasty (DALK) and Descemet's membrane endothelial keratoplasty (DMEK). DESIGN: Retrospective analysis of a nonrandomized, consecutive, interventional case series. PARTICIPANTS: One hundred ten eyes with anterior stromal disease suitable for DALK and 110 eyes with endothelial disease suitable for DMEK underwent surgically successful split cornea transplantation combining both procedures within 7 days after splitting. METHODS: Split donor storage times (splitting to grafting) and total storage times (death to grafting) were correlated with the 1-year functional and morphologic outcomes after DALK and DMEK surgery using a Spearman correlation coefficient and a Mann-Whitney U test. MAIN OUTCOME MEASURES: Best spectacle-corrected visual acuity (BSCVA), endothelial cell density, and complication rates within 12 months of follow-up. RESULTS: The mean split donor storage time was 35 ± 47 hours (range, 0-162 hours) after splitting for anterior donor grafts and 21 ± 40 hours (range, 0-158 hours) for posterior grafts. The mean total storage time was 352 ± 108 hours (range, 108-678 hours) for anterior lamellas and 339 ± 109 hours (range, 96-630 hours) for posterior lamellas. One year after DALK, the mean BSCVA was 20/30 (range, 20/50-20/20), endothelial cell loss was 8% (range, 2%-16%), and the complication rate (Descemet's folds, epitheliopathy, loose sutures) was 18%. One year after DMEK, the mean BSCVA was 20/25 (range, 20/40-20/16), endothelial cell loss was 41% (range, 17%-63%), and the complication rate (partial graft detachment) was 62%. For DALK and DMEK, no significant association was observed between split donor storage time as well as total storage time and BSCVA (P ≥ 0.409), endothelial cell loss (P≥0.236), or complication rate (P ≥ 0.647) within 1 year of follow-up. CONCLUSIONS: Anterior and posterior donor tissue may be stored safely for up to 1 week in organ culture before use in DALK and DMEK surgery. This simplifies the clinical feasibility of split cornea transplantation to reduce donor shortage and cost in corneal transplantation in the future. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Descemet membrane endothelial keratoplasty in eyes with glaucoma implants.

PURPOSE: This study aims to analyze the feasibility of Descemet membrane endothelial keratoplasty (DMEK) in the management of corneal endothelial decompensation in eyes with glaucoma implants. CASE REPORT: A 62-year-old male with bullous keratopathy after trabeculectomy and Baerveldt shunt implantation for contusion glaucoma of the right eye (case 1) underwent surgical tube trimming with a DMEK procedure. A 54-year-old male with Descemet stripping automated endothelial keratoplasty (DSAEK) failure and dislocation in the presence of an Ahmed glaucoma valve and an artificial iris in the right eye (case 2) was treated by removal of the DSAEK graft and subsequent DMEK procedure. In both eyes, the DMEK graft could be successfully inserted, unfolded, positioned in front of the glaucoma tube, and attached to the host stroma by air injection into the anterior chamber. Postoperatively, both corneas cleared with complete graft attachment and stable glaucoma tube position. After 3 days, peripheral graft detachment occurred in case 1 and was managed successfully with one intracameral air reinjection. Case 2 revealed intraocular pressure (IOP) elevation up to 30 mm Hg in the immediate postoperative period, treated successfully by antiglaucoma medications. Within 1-year follow-up, visual acuity improved from hand movements to 20/63 and 20/32, respectively; endothelial cell density decreased by 36% and 42%, respectively; and the IOP ranged between 7 and 14 mm Hg in both cases without treatment. CONCLUSIONS: Descemet membrane endothelial keratoplasty seems to be feasible in the management of corneal endothelial decompensation in eyes with glaucoma implants. Graft attachment, IOP, and endothelial cell density should be followed up closely.

[Inherited retinal diseases in Germany-Challenges in health care supply structure and diagnostics]. / Erbliche Netzhautdystrophien in Deutschland ­ Versorgungsstrukturelle und diagnostische Herausforderungen.

BACKGROUND: Inherited retinal diseases (IRD) are rare eye diseases and pose high diagnostic challenges. A care structure with few highly specialized centers in Germany, misdiagnosis due to the lack of molecular genetic testing, and a lack of a central registry lead to a lack of reliable information on the prevalence and distribution of IRDs in Germany. METHODS: Based on clinical data from an ophthalmological center and molecular data from a genetic center as well as a nationwide health insurance data query, we estimated the prevalence of IRDs in Germany in addition to collecting information on their phenotypic and genotypic distribution. RESULTS: The median travelling distance to the ophthalmological center was 60 km. The most frequent diagnoses were retinitis pigmentosa, macular dystrophy and general retinal dystrophy. Molecular genetic testing was performed in 87% of patients with clinical suspicion of IRD, with marked differences in frequencies among age cohorts. The molecular genetic detection rate in the genetic center was 51%. The prevalence of inherited retinal dystrophy in Germany determined by health insurance data retrieval was approximately 1:1150. CONCLUSION: Many patients must travel long distances to visit specialized clinics for IRDs with access to genetic testing. To obtain more reliable numbers on the prevalence in Germany, routine molecular genetic testing, and a national registry for IRD detection are needed.

[Diagnosis of inherited retinal dystrophies. Relevance of molecular genetic testing from the patient's perspective]. / Diagnostik erblicher Netzhautdystrophien. Stellenwert molekulargenetischer Diagnostik aus Patientenperspektive.

BACKGROUND: The diagnostic process of inherited retinal dystrophies (IRD) is impeded by their low prevalence and the variability of the clinical presentations; however, for patients a valid diagnosis is vital for future planning and evaluating the potential of an appropriate early treatment to delay disease progression. OBJECTIVE: Aim of the current study was to outline the patients' journeys until they receive the final diagnosis. This should help uncover diagnostic shortcomings and highlight potential for improvement with respect to the use of genetic diagnostic testing. MATERIAL AND METHODS: Data were collected by questionnaires and an online survey conducted by the self-help association PRO RETINA Deutschland e. V. among patients with IRD. Data were analyzed by descriptive statistics. RESULTS: From 15 March to 22 April 2021, 183 questionnaires were completed and 42 online interviews conducted. The surveyed population consisted of 48% female patients, mean age was 55 years and first symptoms occurred at a mean age of 22 years. On average about 14 years passed from first symptoms until final diagnosis. Only 66% of the patients reported that they had received at least 1 diagnostic genetic testing; less than half of the patients (47%) received genetic counseling. The huge majority of patients (85%) would be interested in gene therapy. CONCLUSION: From the perspective of affected patients, a shortening of the time to diagnosis, the use of molecular genetic testing and the offer of genetic counseling are important to improve patient care for patients with IRD.

Dry anophthalmic socket syndrome - morphological alterations in meibomian glands.

PURPOSE: To evaluate morphological alterations of meibomian glands (MGs) in the dry anophthalmic socket syndrome (DASS). METHODS: Fifteen unilateral anophthalmic patients wearing cryolite glass prosthetic eyes were enrolled. All patients with clinical blepharitis or other significant eyelid abnormalities were excluded. In vivo laser scanning confocal microscopy (LSCM) of the MGs in the lower eyelids both on the anophthalmic side and the healthy fellow eye was performed to quantify acinar unit density, acinar unit diameter, acinar unit area, meibum secretion reflectivity, the inhomogeneous appearance of the glandular interstice, and inhomogeneous appearance of the acinar walls. RESULTS: The lower eyelids of the anophthalmic sockets revealed a significant reduction of the acinar unit density (p = 0.003) as well as a significantly more inhomogeneous appearance of the periglandular interstices (p = 0.018) and the acinar unit walls (p = 0.015) than the healthy fellow eyelid. However, there were no significant differences regarding the acinar unit diameter, acinar unit area, and meibum secretion reflectivity of the MGs on the anophthalmic side compared to the healthy fellow eyelid (p ≥ 0.05, respectively). CONCLUSIONS: The eyelids of anophthalmic sockets without clinical blepharitis demonstrate a reduced density of MG acinar units and a more inhomogeneous appearance of the periglandular interstices and the acinar unit walls. This can cause meibomian gland dysfunction contributing to DASS and suggests early treatment of these symptomatic patients, even in the clinical absence of any blepharitis signs.

VEGF188 promotes corneal reinnervation after injury.

Vascular endothelial growth factor A (VEGF) induces angiogenesis and vascular hyperpermeability in ocular tissues and is therefore a key therapeutic target for eye conditions in which these processes are dysregulated. In contrast, the therapeutic potential of VEGF's neurotrophic roles in the eye has remained unexploited. In particular, it is not known whether modulating levels of any of the 3 major alternatively spliced VEGF isoforms might provide a therapeutic approach to promote neural health in the eye without inducing vascular pathology. Here, we have used a variety of mouse models to demonstrate differences in overall VEGF levels and VEGF isoform ratios across tissues in the healthy eye. We further show that VEGF isoform expression was differentially regulated in retinal versus corneal disease models. Among the 3 major isoforms - termed VEGF120, VEGF164, and VEGF188 - VEGF188 was upregulated to the greatest extent in injured cornea, where it was both necessary and sufficient for corneal nerve regeneration. Moreover, topical VEGF188 application further promoted corneal nerve regeneration without inducing pathological neovascularization. VEGF isoform modulation should therefore be explored further for its potential in promoting neural health in the eye.

Transient Ingrowth of Lymphatic Vessels into the Physiologically Avascular Cornea Regulates Corneal Edema and Transparency.

Lymphangiogenesis is essential for fluid homeostasis in vascularized tissues. In the normally avascular cornea, however, pathological lymphangiogenesis mediates diseases like corneal transplant rejection, dry eye disease, and allergy. So far, a physiological role for lymphangiogenesis in a primarily avascular site such as the cornea has not been described. Using a mouse model of perforating corneal injury that causes acute and severe fluid accumulation in the cornea, we show that lymphatics transiently and selectively invade the cornea and regulate the resolution of corneal edema. Pharmacological blockade of lymphangiogenesis via VEGFR-3 inhibition results in increased corneal thickness due to delayed drainage of corneal edema and a trend towards prolonged corneal opacification. Notably, lymphatics are also detectable in the cornea of a patient with acute edema due to spontaneous Descemet´s (basement) membrane rupture in keratoconus, mimicking this animal model and highlighting the clinical relevance of lymphangiogenesis in corneal fluid homeostasis. Together, our findings provide evidence that lymphangiogenesis plays an unexpectedly beneficial role in the regulation of corneal edema and transparency. This might open new treatment options in blinding diseases associated with corneal edema and transparency loss. Furthermore, we demonstrate for the first time that physiological lymphangiogenesis also occurs in primarily avascular sites.

Ophthalmological manifestations of Parry-Romberg syndrome.

Parry-Romberg syndrome is a rare disease characterized by slowly progressive atrophy affecting facial subcutaneous tissues, including the underlying muscles and osteocartilaginous structures. Various periocular, ocular, and neuro-ophthalmological manifestations have been described in Parry-Romberg syndrome. The most common periocular disorders include enophthalmos, eyelid, and orbit alterations. The most frequent ocular disorders include corneal and retinal changes, and the most common neuro-ophthalmological disorders involve optic nerve, ocular motor and pupillary dysfunction. Besides the characteristic facial abnormalities, systemic manifestations may occur, including neurologic, dermatologic, cardiac, endocrine, infectious, orthodontic, and maxillofacial disorders. So far, mainly brief case reports describe these ophthalmological findings. Therefore, we summarize the ocular, periocular, and neuro-ophthalmological findings in detail, describe diagnostic modalities, and outline therapeutic options.

In Situ Corneal Cross-Linking for Recurrent Corneal Melting After Boston Type 1 Keratoprosthesis.

PURPOSE: To present a new treatment modality for recurrent corneal melting in a patient with a Boston type I keratoprosthesis (B-KPro) including in situ corneal cross-linking (CXL) and lamellar keratoplasty (LKP) as combined treatment. METHODS: Case report. RESULTS: Our report concerns a 27-year-old man whose case history involved a severe chemical burn of his left eye. After failed penetrating keratoplasty and limbal stem cell transplantation, the patient underwent B-KPro implantation. Starting 1 month after surgery, recurrent corneal melting around the B-KPro developed, which was eventually treated by combining LKP, amniotic membrane transplantation, and in situ CXL. Optical coherence tomography imaging and follow-up for 12 months showed stable corneal healing without new melting or erosion. The ultraviolet A treatment did not seem to damage the material of the B-KPro. CONCLUSIONS: In situ CXL using riboflavin and ultraviolet A light combined with LKP and amniotic membrane transplantation can be an effective management option to treat recurrent corneal melting after B-KPro implantation.

Novel lamellar, flap-based tattooing techniques for corneal opacities in scarred and vascularized blind eyes.

PURPOSE: The aim of this study was to describe novel, flap-based tattooing techniques for the treatment of disfiguring corneal scars in blind eyes. METHODS: Several new modifications of intrastromal corneal tattooing techniques were performed in 6 patients. In corneas with a low risk of perforation, a large limbus-to-limbus lamellar flap was prepared, and the tattooing dyes were spread over the entire stromal bed. After additional puncturing of the dyes into the stroma, the flap was closed and sutured ("large flap technique"). In fragile corneas where convenient preparation of a large flap was not possible, a central small flap was prepared, and the "pupil" was tattooed in analogy ("small flap technique"). Afterward, the corneal periphery corresponding to the "iris" was tattooed, either by puncturing or injecting the dye into peripheral intrastromal tunnels ("tunnel technique"). RESULTS: Two eyes were tattooed using a large flap, and 4 eyes were tattooed using a small flap. Here, the corneal periphery of 3 eyes was tattooed by puncturing, whereas 1 eye was tattooed using the tunnel technique. All tattooing procedures were performed without complications and with good cosmetic results. CONCLUSIONS: These novel, flap-based tattooing techniques are alternatives to previously reported procedures and can be adapted to the individual corneal constitution. Further, the tunnel technique is an easy-to-perform method that provides good tattooing results.

Spontaneous long-term course of persistent peripheral graft detachments after Descemet's membrane endothelial keratoplasty.

BACKGROUND: Peripheral corneal graft detachment after Descemet's membrane endothelial keratoplasty (DMEK) is a frequently occurring postoperative complication. The natural course of these persistent peripheral detachments over time is not known. METHODS: 166 patients were surveyed by slit-lamp-adapted optical coherence tomography (SL-OCT) directly after surgery, during first postoperative week, 4 weeks, 3, 6 and 12 months, postoperatively. Patients with a persistent peripheral graft detachment 4 weeks after DMEK (n=16) were observed for their spontaneous course up to 1 year postoperatively. RESULTS: Persistent graft detachments could be characterised into two phenotypes: peripheral roll (n=11; 69%) and laminar detachment (n=5; 31%). Maximal length of the detachment did not change in peripheral rolls during observation period (12 months vs 4 weeks, 578±122 µm vs 593±106 µm, p=0.74), whereas laminar detachments spontaneously attached to the host's stroma (12 months vs 4 weeks, 0 µm vs 1088±295 µm, p≤0.001). Central corneal thickness and (peripheral) corneal thickness above the detached area did not significantly change in either group. CONCLUSIONS: Persistent peripheral graft detachments after DMEK occurred in 10% of patients and had two distinct OCT-phenotypes. Peripheral rolls did not change during the first 12 months, postoperatively. By contrast, peripheral laminar detachments attached spontaneously even months after surgery. Corneal thickness reduction was only observed above peripheral laminar detachment, but not above peripheral rolls.

Small-Fiber Neuropathy Is Associated With Corneal Nerve and Dendritic Cell Alterations: An In Vivo Confocal Microscopy Study.

PURPOSE: In patients with small-fiber neuropathy (SFN), noninvasive diagnostic tests that allow accurate monitoring of disease progression are urgently needed. The aim of this study was to assess corneal trigeminal small sensory nerves and immune cells by in vivo corneal confocal microscopy (CCM) in SFN. METHODS: In this prospective single-center study, 14 patients with histologically confirmed SFN were analyzed. CCM parameters [corneal nerve fiber density (NFD); the total number of nerves, main trunks, and branches; nerve tortuosity; and dendritic cell density] were compared with 14 age-matched healthy controls and correlated with clinical symptoms, disease course, and histopathological findings. RESULTS: Corneal NFD (15,489.3 ± 5927.6 µm/mm² vs. 22,687.1 ± 4328.7 µm/mm²; P = 0.001) and the total number of nerves (10.4 ± 4.6/frame vs. 18.5 ± 4.8/frame; P < 0.0001) were significantly reduced in patients with SFN. In contrast, nerve tortuosity was significantly increased (2.2 ± 0.3 vs. 1.7 ± 0.5; P = 0.02). Corneal NFD did not correlate with intraepidermal NFD (ρ = -0.158; P = 0.5) or clinical symptoms (cold P = 0.1; prickling P = 0.2; burning P = 0.8; formication P = 0.7; stabbing P = 0.4; rubbing 0.1; pressure P = 0.1). The average dendritic cell density was increased in SFN (33.5 ± 57.5 cells/mm² vs. 16.1 ± 13.7 cells/mm²) but did not reach significance (P = 0.7). CONCLUSIONS: CCM provides parameters that reliably indicate injury to sensory afferents of the trigeminal nerve in patients with SFN. Our data suggest that CCM may serve both as a noninvasive diagnostic test and as a surrogate marker in SFN.