| Popis: |
The cornea is the clear window of the eye and its main refractive media. Corneal avascularity is essential to maintain this function, and this is evolutionarily highly conserved. Corneal vascularisation can result from different types of insults, causing reduced vision and posing a threat to the survival of corneal grafts. We prospectively reviewed 165 patients with corneal vascularisation establishing a reproducible classification of corneal vessels. We classified corneal vessels in to young active, old active, mature, partially regressed and regressed vessels. Patterns of vascularisations differed with aetiology as viral keratitis inducing more severe vascularisation most association with lipid deposition in the cornea. Acanthamoeba keratitis however induced less vascularisation despite severe corneal inflammation. Fine needle diathermy was found to be safe and effective method of treating corneal vascularisation and its effectiveness could be improved further by appropriate selection. Subconjunctival injection of Ranibizumab, which is a fragment of a monoclonal antibody (Fab) created form the same mouse antibody as bevacizumab, was effective in regressing corneal vascularisation initially; this was not maintained with a single dose in the presence of active inciting inflammatory process in the cornea. This reinforces the dictum that as long as the stimulus for vascularisation is not addressed measures to reduce vascularisation have only a temporary effect. Fine needle diathermy and anti angiogenic treatments can form components of an overall strategy to mitigate risk of rejection or in dealing with refractory episodes of rejection in the cornea. Isolation of conjunctival vascular endothelial cells proved very challenging. The widely used human umbilical cord endothelial cells also proved great variation in their cell surface marker expression and phenotypic characteristics across different passages. This highlighted the wide variation to be expected and the need for specificity in the targeted population of cells used in designing angiogenesis experiments. With the use of human umbilical cord endothelial cells we demonstrated the in-vitro anti angiogenic effect of the amniotic membrane. The amniotic membrane significantly reduced endothelial cell proliferation, migration and tube formation. |
