[Preconditioning of vascularized high-risk eyes using fine-needle diathermy and cross-linking]. / Präkonditionierung von vaskularisierten Hochrisikoaugen mittels Feinnadeldiathermie und Crosslinking.

BACKGROUND: The risk of allograft rejection following high-risk keratoplasty increases with the area of corneal neovascularization. Pharmaceutical and physical regression of corneal neovascularization before keratoplasty may offer the potential to reduce the risk of graft rejection after high-risk keratoplasty. OBJECTIVE: This article provides a review of the literature on the preconditioning of vascularized high-risk eyes using fine-needle diathermy and corneal cross-linking (preoperative preconditioning by lymphangioregression). METHODS: A literature search was carried out in PubMed and a summary of own data is presented. RESULTS: Animal experimental studies showed that both fine-needle diathermy and corneal cross-linking lead to a regression of corneal neovascularization and prolong graft survival after high-risk keratoplasty. Furthermore, studies from our institute provide first evidence that both procedures also lead to a reduction of corneal neovascularization in the clinical practice and thus potentially reduce the risk of allograft rejection after subsequent high-risk keratoplasty. DISCUSSION: Fine-needle diathermy and corneal cross-linking provide effective therapeutic approaches for angioregressive treatment and seem to prolong graft survival following high-risk keratoplasty. Larger prospective and controlled clinical trials are needed to further investigate these promising therapeutic approaches.

[Descemet membrane endothelial keratoplasty (DMEK) for graft failure after penetrating keratoplasty and in vascularized high-risk eyes]. / "Descemet membrane endothelial keratoplasty" (DMEK) bei Transplantatversagen nach perforierender Keratoplastik und in vaskularisierten Hochrisikoaugen.

BACKGROUND: Descemet membrane endothelial keratoplasty (DMEK) is considered the gold standard for the treatment of corneal endothelial dysfunction and generally leads to good postoperative results. Recently, studies have also analyzed the outcome of DMEK in so-called high-risk eyes. MATERIAL AND METHODS: The relevant literature and own data on DMEK for graft failure after penetrating keratoplasty and in vascularized high-risk eyes are presented and discussed. RESULTS: A DMEK for the treatment of transplant failure after penetrating keratoplasty can be considered for eyes without stromal scars and without high astigmatism. A retrospective analysis of 52 patients with failed penetrating grafts showed that DMEK leads to a significant increase in visual acuity, albeit to a lesser extent than after primary DMEK. Rejection and transplant failure rates seem to be similar those seen after penetrating re-keratoplasty and are thus higher than after primary DMEK. A DMEK might also be a feasible option for eyes with corneal neovascularization and stromal edema without stromal scars. A retrospective analysis of 24 eyes with at least 2 vascularized corneal quadrants demonstrated that DMEK leads to a significant improvement in visual acuity and regression of corneal neovascularization. The rejection rate in this cohort was 4.2% and is therefore slightly higher than after low-risk DMEK in eyes without corneal neovascularization but still much better compared to penetrating keratoplasty. CONCLUSION: Indications for DMEK are expanding and it can be a therapeutic option for transplant failure after penetrating keratoplasty with acceptable outcomes. Furthermore, DMEK seems to be a good option for the treatment of endothelial dysfunction in vascularized high-risk eyes without stromal scars.

[Treatment of vascularized high-risk eyes with a Boston keratoprosthesis]. / Versorgung von vaskularisierten Hochrisikoaugen mittels Boston-Keratoprothese.

BACKGROUND: In severely compromised and vascularized high-risk eyes, the Boston keratoprosthesis procedure is often the last treatment option. The transparency of the optics is not impaired by endothelial immune reactions. METHODS: This review article discusses relevant literature as well as our own data and experiences with the Boston keratoprosthesis in high-risk eyes. The relevant complications as well as the postoperative management are discussed. RESULTS: In more than 60% of the high-risk eyes a long-term increase in visual acuity can be achieved. Keratoprosthesis retention rates show a variable span with reported mean 5­year retention rates of 75%. The most common postoperative complications include the formation of a retroprosthetic membrane and keratolysis in up to 50% each. More than 70% of the eyes already suffer from (secondary) glaucoma preoperatively, so that glaucoma surgery is performed simultaneously in at least 20% of cases and in the postoperative course further antiglaucomatous surgery is necessary in up to 31%. Vitreoretinal complications include, in particular, sterile vitritis and infectious endophthalmitis but persistent hypotonia is also described in one third of patients. CONCLUSION: The Boston keratoprosthesis is an alternative to conventional corneal replacement if the prognosis for allogeneic transplants is poor. Postoperative complications are common; therefore, postoperative management plays an important role. For vascularized high-risk eyes, however, it is often the only remaining option for visual rehabilitation.

Phase-specific functions of macrophages determine injury-mediated corneal hem- and lymphangiogenesis.

Macrophages are critical mediators of injury-associated corneal hemangiogenesis (HA) and lymphangiogenesis (LA). Yet, molecular regulators of the hem- and lymphangiogenic potential of corneal wound macrophages are poorly understood. Using two different mouse models of acute (perforating corneal incision injury) and chronic (corneal suture placement model) corneal injury, here we identified distinct functions of early- versus late-phase corneal wound macrophages in corneal HA and LA. Whereas early-phase wound macrophages are essential for initiation and progression of injury-mediated corneal HA and LA, late-phase wound macrophages control maintenance of established corneal lymphatic vessels, but not blood vessels. Furthermore, our findings reveal that the hem- and lymphangiogenic potential of corneal wound macrophages is controlled by the type of the corneal damage. Whereas perforating corneal incision injury induced primarily wound macrophages with lymphangiogenic potential, corneal suture placement provoked wound macrophages with both hem- and lymphangiogenic potential. Our findings highlight a previously unrecognized injury-context dependent role of early- versus late-phase corneal wound macrophages with potential clinical impact on therapy development for sight-threatening corneal neovascular diseases.

[10 years of Descemet membrane endothelial keratoplasty in Fuchs endothelial corneal dystrophy : What have we learned?] / Zehn Jahre "Descemet membrane endothelial keratoplasty" bei Fuchs-Dystrophie : Was haben wir gelernt?

BACKGROUND AND OBJECTIVE: Descemet membrane endothelial keratoplasty (DMEK) has increased in popularity since its introduction over 10 years ago. This article presents a summary of the experiences of the past years collected at the Department of Ophthalmology at the University of Cologne. METHODS: A literature review of DMEK studies primarily from the Department of Ophthalmology at the University of Cologne, Germany was carried out. Own experiences in the fields of donor selection and graft preparation, DMEK surgery, complication management and postoperative treatment are summarized. RESULTS: Since the introduction of DMEK experience has been gained and ongoing improvements have occurred ranging from donor-recipient allocation to postoperative follow-up. These led to a better reproducibility of the intervention for the surgeon, to a better postoperative result and to a reduction of the complication rate. DISCUSSION: The DMEK represents a safe and individualized procedure for endothelial transplantation for corneal endothelial dysfunction. Continuing development of the method leads to optimization and safer results.

[Boston type I keratoprosthesis implantation technique : Video article]. / Technik der Boston-Typ-I-Keratoprothesen-Implantation : Videobeitrag.

BACKGROUND: Keratoprosthetics refer to the replacement of human corneal tissue with an artificially produced exchange product. The most widely implanted keratoprosthesis worldwide is the Boston Type I Keratoprosthesis (BI-KPro, Massachusetts Eye and Ear Infirmary, Boston, MA, USA). METHODS: This video article demonstrates the surgical technique of BI-KPro implantation as routinely performed at this institution. In addition, an overview of the surgical indications, patient consent, anesthesia and positioning, postoperative treatment and complications as well as the evidence of the technique is provided in the article based on experience with 31 BI-KPro implantations. RESULTS: The indications for BI-KPro primarily include patients in a high-risk keratoplasty setting particularly after repeatedly failed keratoplasty. A thorough patient examination and assessment of the indications as well as detailed disclosure of information to the patient about the individual prognosis, the risk profile, the postoperative therapy and follow-up enable a positive postoperative result. CONCLUSION: The BI-KPro provides an established and relatively standardized option for surgical treatment of eyes in a high-risk keratoplasty setting. Patients should be preoperatively informed with respect to the individual prognosis, complication profile and life-long follow-up.

[Research during residency]. / Forschung in der Weiterbildung.

Physicians in German university hospitals feel themselves confronted with a multiple workload due to patient care, teaching and research. Furthermore, this load is increased by administrative duties and conference trips; however, the framework conditions surrounding this multiple workload of patient care, research and teaching as well as administrative activities are becoming increasingly more difficult. In particular, there is very little free time for scientific activities. Research is therefore often carried out during leisure time. The path of the clinician scientist, a duo of scientiific and clinical activities, opens up many possibilities; however, the question arises whether the career path of a clinician scientist is even possible under the current conditions or whether this is an endangered "species". This article presents the problems but solutions and ideas are also developed for optimum organization of this multiple workload and to appreciate the additional value of clinician scientists.

[Boston-keratoprosthesis : Preliminary experiences in 13 high-risk eyes from the Department of Ophthalmology of the University of Cologne]. / Boston-Keratoprothese : Erste Erfahrungen bei 13 Hochrisikoaugen aus der Kölner Universitätsaugenklinik.

BACKGROUND: Corneal transplantation in high-risk eyes remains a challenge. The Boston keratoprosthesis (B-KPro) is a final option for patients with end-stage corneal disease and a poor prognosis with conventional penetrating keratoplasty. In this article the results of the first 13 eyes that received a B-KPro type I at the Department of Ophthalmology, University of Cologne, Germany are reported and the usefulness of postoperative slit-lamp optical coherence tomography (SL-OCT) for control purposes is evaluated. MATERIAL AND METHODS: All recipients of a B-KPro type I between September 2013 and May 2015 were included in the study. The feasibility of the operation, clinical outcomes, complications and revision surgery were investigated. The visualization of wound healing by SL-OCT was analyzed. RESULTS: The age of the patients ranged from 26 to 92 years (mean 57.3 ± 20.9 years). In all 13 eyes from 12 patients (6 males and 6 females) dense corneal opacification with vascularization and sometimes also conjunctivalization was present. Preoperative visual acuity was reduced and ranged from mere light perception up to a maximum of 1/35 eye chart. All 13 eyes could be supplied with a B-KPro type I without any intraoperative complications, in 6 eyes no significant postoperative complications occurred, whereas in 7 eyes various additional surgical interventions were required and 1 B-KPro could not be preserved. Postoperative visual acuity ranged from light perception to 20/32 and was significantly improved in 85 % of the treated eyes. The use of SL-OCT reproducibly allowed the postoperative assessment of stromal thinning. CONCLUSION: The B-KPro provides the possibility of visual rehabilitation in high-risk eyes that could never be achieved without artificial cornea replacement. Despite higher complication rates this technique represents a significant progress in the surgical treatment of complex corneal pathologies. Regular and intensive postoperative controls are necessary to achieve good long-term results.

Blockade of CCR7 leads to decreased dendritic cell migration to draining lymph nodes and promotes graft survival in low-risk corneal transplantation.

The chemokine receptor CCR7 is essential for migration of mature dendritic cells (DCs) to the regional lymph nodes, and it has been shown that blocking of CCR7 improves graft survival after high-risk corneal transplantation in vascularized recipient corneas. However, it is so far unknown whether blocking of CCR7 reduces migration of DCs from the avascular cornea to the draining lymph nodes and whether this leads to improved graft survival also in the low-risk setting of corneal transplantation, which accounts for the majority of perforating transplantations performed. Therefore, in this study, pellets containing Freund's adjuvant and bovine serum albumin (BSA) conjugated to Alexa488 fluorescent dye were implanted into the corneal stroma of BALB/c mice to analyze antigen uptake by corneal DCs and their migration to the regional lymph nodes. After pellet implantation, mice were either treated by local administration of a CCR7 blocking fusion protein that consisted of CCL19 fused to the Fc part of human IgG1 or a control-IgG. In vivo fluorescence microscopy showed uptake of Alexa488-conjugated BSA by corneal DCs within 8 h. Furthermore, analysis of single cell suspensions of draining lymph nodes prepared after 48 h revealed that 2.1 ± 0.3% of CD11c(+) cells were also Alexa488(+). Importantly, DC migration was significantly reduced after topical administration of CCL19-IgG (1.2 ± 0.2%; p < 0.05). To test the effect of CCR7 blockade on graft rejection after allogeneic low-risk keratoplasty, corneal transplantations were performed using C57BL/6-mice as donors and BALB/c-mice as recipients. Treatment mice received two intraperitoneal loading doses of CCL19-IgG prior to transplantation, followed by local treatment with CCL19-IgG containing eye drops for the first two weeks after transplantation. Control mice received same amounts of control-IgG. Kaplan-Meier survival analysis showed that in the CCL19-IgG treated group, 76% of the grafts survived through the end of the 8 week observation period, whereas 38% of the grafts survived in the control group (p < 0.05). Taken together, our study shows that blockade of CCR7 reduces the migration of mature corneal DCs to the draining lymph nodes and leads to improved graft survival in low-risk corneal transplantation.

[The situation of residents in ophthalmology in Germany: Results of an online survey]. / Situation der Assistenzärztinnen und -ärzte in der Ophthalmologie in Deutschland : Ergebnisse einer Online-Umfrage.

PURPOSE: The main purpose of the present survey was to describe the situation of residents in ophthalmology in Germany, including professional aims and plans for the future. By evaluating the current conditions, potential deficits should be identified which could lead to demand-oriented approaches for improvement. METHODS: The online questionnaire was sent out per e-mail to 1100 German residents. The rate of received answers was 30.1 % (334 completed questionnaires). RESULTS: Of the participants 68 % were female,32 % were male (mean age 31.8 years), one third of the participants had children, 44.6 % worked at university institutions, 54.4 % at non-university institutions and 45.5 % considered themselves as well-trained. Deficits during residency training were seen in the field of neuro-ophthalmology and ophthalmic surgery. The evaluation of the residency in total revealed an overall average grade of 2.9 ("satisfactory"). Of the physicians 35.5 % reported to be actively involved in research projects and 21.9 % reported pursuing an academic career. Almost 50 % of the participant residents aimed to work in a private practice after residency and 15 % aimed to work at an university hospital. CONCLUSION: The present survey revealed representative data because of the acceptable return rate and participating residents from all different educational levels (1st to 5th year). The survey can therefore help to characterize the current situation of residents in ophthalmology in Germany and to develop demand-oriented possibilities for improvement.

[Decellularized collagen matrix from tilapia fish scales for corneal reconstruction (BioCornea)]. / Dezellularisierte Kollagenmatrix aus der Schuppe des Tilapia-Fisches als Hornhautersatz ("BioCornea").

BACKGROUND: The worldwide need for donor corneal tissue clearly exceeds the availability of transplantable human tissue; therefore, recent efforts aim to identify and characterize alternative tissues, such as decellularized collagen scaffolds. OBJECTIVES: The transparent fish scales of tilapia (Oreochromis mossambicus) were analyzed as a potential alternative for corneal reconstruction ("BioCornea"). MATERIAL AND METHODS: The article gives a review of the literature and own preliminary results. After decellularization the tissue characteristics of the fish scales, the repopulation with corneal epithelium and stromal cells, immunogenicity, the feasibility of corneal transplantation and the angiogenic properties were analyzed in vitro and in various animal models. RESULTS: The fish scales mainly consist of collagen type I and show an architecture that is similar to the human cornea. Corneal epithelium and stromal cells are able to grow over and into the scaffold. It is possible to transplant fish scales in various animal models without severe inflammatory responses. Furthermore, in mice, less blood and lymphatic vessels grow into the xenograft when compared to conventional allogenic transplants. CONCLUSION: Preliminary results with decellularized tilapia fish scales as an alternative for corneal reconstruction ("BioCornea") are promising.

Regression of mature lymphatic vessels in the cornea by photodynamic therapy.

BACKGROUND: Corneal (lymph) angiogenesis is a predominant risk-factor for immune rejection after transplantation. Techniques to regress pre-existing pathological corneal lymphatic vessels prior to transplantation are missing so far. Therefore we analysed the possibility to regress corneal lymphatic vessels by photodynamic therapy (PDT), after intrastromal verteporfin injection. METHODS: Combined hemangiogenesis and lymphangiogenesis was induced in female BALB/c mice using the murine model of suture-induced inflammatory neovascularisation. Thereafter, the treatment group received an intrastromal injection of verteporfin (controls: phosphate buffered saline (PBS)) followed by PDT. Corneas were excised at different time points (1 day, 5 days and 10 days) after PDT and corneal whole mounts were stained with CD31 and LYVE-1 to quantify hemangiogenesis and lymphangiogenesis. RESULTS: Whereas blood vessels showed no significant reduction after PDT, lymphatic vessels could significantly be reduced with PDT after intrastromal verteporfin injection: 1 day after PDT, lymphatic vessels were reduced by 62% (p=0.20). After 5 days and 10 days, lymphatic vessels were reduced by 51% and 48% (p<0.001), respectively. CONCLUSIONS: This study for the first time shows that PDT after corneal intrastromal verteporfin injection can selectively regress lymphatic vessels. This may become a new 'preconditioning strategy' to reduce pre-existing corneal lymphatic vessels prior to transplantation and thereby reduce allograft rejection in high-risk patients.

"OSMO-UT-DSAEK" using THIN-C medium.

BACKGROUND: When performing ultra-thin Descemet's stripping automated endothelial keratoplasty (UT-DSAEK), the quality of the stromal interface and stromal thickness seem to be critical for visual outcome. The aim of this study was to investigate whether additional osmotic deswelling prior to UT-DSAEK improves the quality of the cut surface and leads to a more reliable and deeper cut in UT-DSAEK ("OSMO-UT-DSAEK"). METHODS: Seventeen human donor corneas not usable for transplantation were used in this experiment. After standard deswelling with culture Medium II, ten corneas were randomly assigned to be additionally deswollen within THIN-C medium. The other remaining seven corneas were put back into culture Medium II. All corneas were placed in an artificial anterior chamber system (Moria); a double path cutting procedure using a microkeratome (Moria) was then performed. Corneal thickness was measured by ultrasound biomicroscopy and in paraffin-embedded slides, followed by histological grading of the cut surface. RESULTS: Stromal interface smoothness significantly improved after preconditioning in THIN-C medium (Pearson P = 0.019). The correlation of the corneal thickness obtained by UBM (mean 706 ± SD 208 µm) and histology (mean 530 ± SD 159 µm) was not significant (Pearson r = 0.11, P > 0.05, mean difference 247, 95 % CI [+50;+304]). We found no significant correlation between the microkeratome setting and the actual thickness of the lenticule measured in histological analysis in both media as well as for the first and second cut (first cut: Pearson r = 0.9, P = 0.1, 95 % CI [-10;+96], second cut: Pearson r = 0.9, P = 0.4, 95 % CI [-10;+22]). CONCLUSION: Preconditioning of corneas with THIN-C medium significantly improved the quality of the graft interface in UT-DSAEK, but did not significantly improve the cut precision of the microkeratome.

[Anti(lymph)angiogenic preconditioning prior to keratoplasty]. / Antiangiogene Präkonditionierung vor Keratoplastik.

PURPOSE: The aim of this study is to describe novel therapeutic concepts to promote graft survival in high-risk keratoplasty by targeting (lymph)angiogenesis in the transplant context. METHODS: A PubMed literature search and our own clinical and experimental data are evaluated. RESULTS: There are three options for anti(lymph)angiogenic preconditioning: a) primary prevention of neovascularisation during the disease process, b) secondary prevention by regressing established blood vessels prior to transplantation and (c) tertiary prevention through inhibition of post-keratoplasty neovascularisation. CONCLUSION: Modern topical anti(lymph)angiogenic therapies seem to be able to reduce the risk of graft rejection especially in high-risk keratoplasty.

[Immune reactions after DMEK, DSAEK and DALK]. / Immunreaktionen nach DMEK, DSAEK und DALK.

PURPOSE: The aim of this study is to describe incidence, diagnosis and therapy for endothelial immune reactions after modern lamellar corneal transplantat surgery (DMEK, DSAEK, DALK). METHODS: A PubMed-based literature review and our own clinical and experimental data are evaluated. RESULTS: There is no longer an endothelial immune reaction after DALK for keratoconus. DMEK significantly reduces the risk for endothelial immune reactions after surgery for Fuchs dystrophy. CONCLUSIONS: Modern lamellar corneal transplant techniques such as DALK and DMEK have nearly abolished the risk for endothelial immune reactions in the avascular recipient bed.

[Topical inhibition of angiogenesis at the cornea. Safety and efficacy]. / Topische antiangiogene Therapie an der Hornhaut. Sicherheit und Effektivität.

BACKGROUND: The efficacy and safety of novel topical inhibitors of corneal neovascularisation will be discussed. METHODS: A literature review after a PUBMED search and own clinical and experimental results are presented. RESULTS: The off-label use of Avastin eye drops and GS101 eye drops against insulin receptor substrate (IRS)-1, which have been tested in phase II trial, both seem to be relatively efficient and safe ways to inhibit progressive corneal neovascularisation. Other VEGF antagonists, such as ranibizumab and pegaptanib eye drops also inhibit corneal neovascularisation. CONCLUSIONS: Avastin and GS101 eye drops are the first specific angiogenesis inhibitors for topical inhibition of corneal angiogenesis available for clinical use.

Transient postoperative vascular endothelial growth factor (VEGF)-neutralisation improves graft survival in corneas with partly regressed inflammatory neovascularisation.

BACKGROUND: High-risk keratoplasties are usually performed after an uninflamed and quiescent interval in corneas with partly regressed blood and lymphatic vessels. We analysed whether the inhibition of post-keratoplasty revascularisation in mice with partly regressed corneal vessels ("intermediate-risk") improves graft survival. METHODS: Three interrupted stromal sutures (11-0) in corneas of Balb/c mice (6-8 weeks old) were placed for 6 weeks. Six months after suture removal, penetrating keratoplasty was performed with C57BL/6 donors. The treatment group received a vascular endothelial growth factor-A specific cytokine trap (VEGF Trap) intraperitoneally at days 0, 4, 7 and 14 after keratoplasty (25 mg/kg per mouse; controls received equal amounts of Fc protein). Pathological haemangiogenesis and lymphangiogenesis prior to as well as 3 days or 8 weeks after keratoplasty and graft survival were analysed. RESULTS: Three days after keratoplasty corneal revascularisation was sufficiently reduced by VEGF Trap (haem-vascularised areas 42.7% reduction; lymph-vascularised areas 54.7% reduction). Survival proportions 8 weeks after keratoplasty were 36% in the treatment group compared with 9% in the control group (n = 11; p<0.05). At that time no differences in haemangiogenesis or lymphangiogenesis were observed between the two groups. CONCLUSION: Early transient postoperative induction of haemangiogenesis and lymphangiogenesis and reformation of regressed corneal blood and lymphatic vessels are important for transplant rejections after "intermediate-risk" corneal transplantation.

Improved semiautomatic method for morphometry of angiogenesis and lymphangiogenesis in corneal flatmounts.

Purpose of the study was to describe a novel semiautomatic, quantitative image analysis method based on threshold analysis for morphometry of corneal (lymph)angiogenesis and to test its validity, reliability and objectivity. Murine corneas were vascularized by using a suture-induced neovascularization assay. For immunohistochemistry, flatmounts of the vascularized corneas were stained with LYVE-1 as a specific lymphatic vascular endothelial marker and with CD31 as panendothelial marker. Morphometry of corneal hem and lymphangiogenesis was performed semi-automatically on digital images using image analysis software. Data were analyzed by a paired t-test, intraclass-correlation and systemic difference analysis compared to a manual method. The semiautomatic method based on threshold analysis was more valid in measuring the area covered by blood or lymphatic vessels. Both methods had a good reproducibility with respect to both vessel types (blood vessels: manual: 0.969, semiautomatic: 0.982; lymphatic vessels: manual: 0.951, semiautomatic: 0.966), whereas the systemic difference was significant for both groups measuring lymphatic vessels (manual: p<0.003; semiautomatic: p<0.035) and for the manual method measuring blood vessels (manual: p<0.0001; semiautomatic: p<0.419). The new semiautomatic morphometry method based on threshold analysis provides higher accuracy, is more valid than and at least as reproducible and objective as the manual outlining method. Therefore the semiautomatic method can be used to detect even small effects on hem and lymphangiogenesis in murine corneal flatmounts with greater precision.

Age-related changes in murine limbal lymphatic vessels and corneal lymphangiogenesis.

Important risk factors for graft rejection after corneal transplantation are pathologic corneal lymphangiogenesis and young recipient age. Purpose of this study was to investigate whether there are age-related differences in normal murine limbal and pathologic corneal lymphatic vessels, which could partly explain the unequal outcome of corneal transplantation in young versus old recipients. Furthermore, we investigated whether these observed differences correlate with changes in allograft survival in the murine model of corneal transplantation. Corneal whole mounts from untreated young (aged 6-8 weeks), untreated old (aged 9-15 months) and young and old mice after suture-induced, inflammatory corneal neovascularization were prepared and stained with LYVE-1 as a lymphendothelial marker. Angles of corneal parts with and without a main circumferential limbal lymphatic vessel were measured and then related to the total 360 degrees of corneal circumference. Centrally directed vascular extensions from the main limbal lymphatic vessel ("sprouts") of previously untreated old mice were counted. Concerning the outgrowth of pathologic lymphatic vessels after inflammatory corneal neovascularization, the area covered with pathologic lymphatic vessels was detected by an algorithm on digitized whole mounts using cell--F software. Low-risk allogeneic (C57Bl/6 to BALB/c) corneal transplantations were performed with one recipient group being young, the other group being old mice. In young, untreated mice, 70.5% of the total corneal circumference was covered by a main circumferential limbal lymphatic vessel versus 60.8% in old, untreated mice. Comparing the number of centripedal vascular extensions from the main limbal lymphatic vessel ("sprouts"), untreated old mice had significantly less extensions than young, untreated mice (p<0.001). After an inflammatory stimulus, old mice had significantly less pathologic corneal lymphatic vessels than young mice (42% less, p<0.001). Comparing the survival proportions after corneal transplantation, old recipient mice showed a significantly better graft survival 6 weeks after transplantation (65% versus 33%, p<0.05). Thus, limbal lymphatic vascular sprouts and inflammation-induced pathologic corneal lymphangiogenesis decrease with age. The lower lymphangiogenic potency of older mice may explain the better outcome of corneal transplantations in old recipients, supporting the concept that lymphangiogenesis is an important risk-factor for corneal transplant rejection.