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Electrical stimulation of the retina with extraocular electrodes is a new approach to developing a retinal prosthesis for blind patients. We have evaluated stimulus and electrode configurations for an extraocular retinal prosthesis (ERP). In anesthetized cats, ERP disc electrodes of 1 mm, 2 mm and 3 mm diameter were sutured to the sclera over the lateral(More)
PURPOSE Ocular surface squamous neoplasia (OSSN) is an uncommon tumor of the corneal and conjunctival epithelium associated with risk of permanent visual impairment. The purposes of this study were to (1) identify and localize potential mediators in tissue from patients with OSSN and (2) culture human dysplastic conjunctival epithelial cells (DCECs) to(More)
PURPOSE Pterygia are a common, benign, fibrovascular, and infiltrative process of the corneal-conjunctival junction of unknown pathogenesis. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes active against all components of the extracellular matrix, whose activity is specifically neutralized by tissue inhibitors of MMPs (TIMPs). In the(More)
Cellular responses to changes in pressure are implicated in numerous disease processes. In glaucoma apoptosis of retinal ganglion cells (RGCs) is associated with elevated intra-ocular pressure, however, the exact cellular mechanisms remain unclear. We have previously shown that pressure can induce apoptosis in B35 and PC12 neuronal cell lines, using an in(More)
Pterygium is a common ocular surface disease apparently only observed in humans. Chronic UV exposure is a widely accepted aetiological factor in the pathogenesis of this disease and this concept is supported by epidemiological data, ray tracing models and histopathological changes that share common features with UV damaged skin. The mechanism(s) of(More)
Pressure is a crucial component of the cellular environment, and can lead to pathology if it varies beyond its normal range. The increased intra-ocular pressures in acute glaucoma are associated with the loss of neurons by apoptosis. Little is known regarding the interaction between pressure and apoptosis at the level of the cell. The model developed in(More)
PURPOSE Pterygia are invasive, proliferative fibrovascular growths, with the matrix metalloproteinase (MMP) family of enzymes strongly implicated in the pathogenesis of these lesions. The purpose of this study was to determine the cellular distribution and activation status of matrilysin (MMP-7) in pterygia. METHODS Resected pterygia (n = 8) and normal(More)
BACKGROUND We present a new approach to developing a retinal prosthesis for blind patients based on extraocular stimulation of the eye with disc electrodes. METHODS Experiments to assess the feasibility of using extraocular stimulation in a retinal prosthesis were carried out in anaesthetised adult cats (n=6). A craniotomy and lateral orbital dissection(More)
PURPOSE Light incident at the temporal cornea is focused by the peripheral anterior eye to the nasal limbus, the usual site of pterygium formation. Parameters that may contribute to observed individual variations in the degree of limbal light focusing were assessed. METHODS Computer-assisted optical ray tracing techniques were applied to a human anterior(More)
PURPOSE Pterygia are common ocular surface lesions that are thought to be induced by exposure to ultraviolet (UV) radiation. The hypothesis tested in the current study is that UV radiation modulates the expression of interleukin (IL)-6 and -8, which could promote the neovascularization and chronic inflammation regularly observed in pterygia. METHODS(More)