Epidemiology of dry eye disease in Africa: The sparse information, gaps and opportunities.

Dry eye disease (DED) is an increasingly significant clinical problem in developing countries and/or emerging economies. Existing studies on DED conducted in these areas have largely reported on associations between DED and infectious disease (trachoma) and malnutrition (hypovitaminosis A), but current trends of industrialization, urbanization, and modernization in these areas could result in a shift to other forms of DED. Herein, we review the epidemiology of DED in these geographic areas, highlighting potential causes and risk factors of DED while presenting information on diagnostic tools and algorithms and insight into some treatment modalities of DED that could prove useful to clinicians and investigators in these regions.

[Therapy for Ocular Graft-vs-Host Disease]. / Therapie der okulären Graft-versus-Host-Erkrankung.

Therapy for ocular graft-vs-host disease (ocular GvHD) is challenging for ophthalmologists as progress of the disease often occurs rapidly and is unforeseeable. Primary goal is the preservation or restoration of visual acuity, however, studies on ocular GvHD that have investigated therapeutic concepts are limited. In contrast, most therapeutic recommendations from consensus conferences derive from studies on dry eye diseases other than ocular GvHD. This review demonstrates the available therapies in the following categories: local, systemic, surgical and prophylactic. Primary targets are anti-inflammation, anti-fibrosis and lubrification of the ocular surface. In conclusion, studies strictly on ocular GvHD are needed to enable better evidence-based therapeutic decision-making in the future.

[Basic immunology and current therapeutic concepts in ocular allergy]. / Grundlagen allergischer Erkrankungen der Augenoberfläche und aktuelle medikamentöse Therapiekonzepte.

BACKGROUND: Ocular allergy belongs to the most common ocular diseases globally. Following clinical phenotype and immunopathogenesis different forms of allergy are distinguished, which require different forms of therapeutic approach. This manuscript reviews the basic immunological processes involved in the development of ocular allergies and current and future therapeutic approaches. METHODS: Results of a literature search in PubMed and our own clinical and experimental experience are presented. RESULTS: In the immunopathogenesis of ocular allergy different immune cells such as dendritic cells, B-cells, T-cells, mast cells, eosinophils and regulatory T-cells are involved. Therapeutic approaches focus on either relief of symptoms using antihistamins or mast cell stabilisers or combinations of both. In severe cases steroids or calcineurin inhibitors are used. DISCUSSION: Despite great progress in the investigation of ocular allergy in the past decade several open questions remain, such as the relation of ocular allergy with dry eye disease. Future therapeutic approaches will likely be based on recently identified new aspects such as lymphangiogenesis and will allow better and potentially causal treatment of ocular allergy.

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.

Intravital multidimensional real-time imaging of the conjunctival immune system.

The conjunctiva, as a peripheral mucosal surface, is dependent on the migration of immune cells to facilitate an orchestrated immune response. So far, only limited data to visualize these dynamics directly have been obtained, mainly due to technical and experimental restrictions. To investigate migration on a cellular level, the following conditions need to be met: (1) intravital investigations need to be facilitated by suitable microscopic techniques; (2) tissues need to be investigated in three spatial dimensions and over time; (3) data need to contain detailed information about the tissue character. Whereas the use of confocal laser scanning microscopy allows high-resolution imaging of the superficial conjunctival immune system and enables the recording of rapid cellular migration, intravital two-photon microscopy further enables tracking of individual cells and characterization of cells and structures with unique optical features using autofluorescence detection, fluorescence lifetime measurements and second harmonic generation in deep tissue. Based on current results and experimental studies, two-photon microscopy has the potential for general use in basic research and clinical practice, and would greatly enhance possibilities for diagnosing and analyzing inflammatory processes of the ocular surface. In particular, inflammation in common diseases, such as allergy and dry eye, and its progress under treatment could be investigated in detail.