Central corneal thickness considered an index of corneal hydration of the UVB irradiated rabbit cornea as influenced by UVB absorber.
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UVB radiation from sunlight induces an acute corneal inflammation, photokeratitis, accompanied by changes in corneal hydration. We employed a method of ultrasonic pachymetry for daily examination of central corneal thickness as an index of corneal hydration of the rabbit cornea repeatedly irradiated by UVB radiation (312 nm, daily dose of 0.25 J/cm(2) during three or four days) as influenced by UVB absorber (actinoquinol combined with hyaluronic acid) dropped on the ocular surface during irradiation. One day after the third irradiation procedure the animals were sacrificed and corneas examined immuno-histochemically for peroxynitrite formation, a marker of oxidative damage, the antioxidant aldehyde dehydrogenase 3A1 and endothelial nitric oxide synthase, an enzyme generated nitric oxide. Results show that UV absorber combined with hyaluronic acid protected the cornea against UVB-induced changes in corneal thickness and microscopical disturbances to the cornea (both seen after buffered saline application) until the fourth experimental day. These UVB doses are equivalent to a daily exposure of 2.5 hrs of the human cornea to solar UVB radiation for three consecutive days. It is suggested that actinoquinol/ hyaluronic acid drops might be helpful for the human eye in the defence against photooxidative and other oxidative processes. (+info)
Combining corneal hysteresis with central corneal thickness and intraocular pressure for glaucoma risk assessment.
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A short-term in vivo experimental model for Fuchs endothelial corneal dystrophy.
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PURPOSE: We evaluated the in vivo functionality of a corneal endothelium tissue-engineered using corneal endothelial cells from human patients with Fuchs endothelial corneal dystrophy (FECD). METHODS: A total of 15 healthy cats underwent full-thickness corneal transplantation. All transplants were of xenogeneic human origin and all grafts but two were tissue-engineered. In seven animals the graft corneal endothelium was tissue-engineered using cultured corneal endothelial cells from humans with FECD (TE-FECD). Two control animals were grafted with an endothelium engineered using cultured endothelial cells from normal eye bank corneas (TE-normal). Two controls received a native full-thickness corneal transplant, and four other controls were grafted with the stromal carrier only (without endothelial cells). Outcome parameters included graft transparency (0, opaque to 4, clear), pachymetry, optical coherence tomography, endothelial cell morphometry, transmission electron microscopy (TEM), and immunostaining of function-related proteins. RESULTS: Seven days after transplantation, 6 of 7 TE-FECD grafts, all TE-normal grafts, and all normal native grafts were clear (transparency score >3), while all carriers-only grafts were opaque (score <1). The mean pachymetry was 772 +/- 102 mum for TE-FECD, 524 +/- 11 mum for TE-normal, 555 +/- 48 for normal native, and 1188 +/- 223 mum for carriers only. TEM showed subendothelial loose fibrillar material deposition in all TE-FECD grafts. The TE endothelium expressed Na(+)-K(+)/ATPase and Na(+)/HCO3(-). CONCLUSIONS: Restoration of transparency and corneal thickness demonstrated that the TE-FECD grafts were functional in vivo. This novel FECD seven-day living model suggests a potential role for tissue engineering leading to FECD cell rehabilitation. (+info)
Corneal epithelial thickness mapping by Fourier-domain optical coherence tomography in normal and keratoconic eyes.
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