Retisert (Bausch & Lomb, Rochester, NY) is a tablet containing mg of fluocinolone acetonide that is coated with nonbiodegradable PVA and silicon laminate (Figure 1(b) ). It is 5 mm long, 2 mm wide and mm thick with a release rate of – mcg/d over a period of 30 months. It is inserted into the vitreous cavity and sutured to the sclera through a pars plana surgical technique similar to Vitrasert. In April 2005 it became the first FDA-approved device for use in the treatment of chronic noninfectious posterior uveitis [ 29 ].
Several processes have been implicated in the breakdown of the blood-retinal barrier that leads to ME, including the production of inflammatory mediators (., prostaglandins and interleukin-6), increased amounts of vascular permeability factors (., vascular endothelial growth factor) and the loss of endothelial tight junction proteins. Corticosteroids are thought to have beneficial effects on these processes, but delivering therapeutic concentrations of any medication to the retina while limiting systemic exposure presents a challenge. Intra-vitreal injections of the corticosteroid triamcinolone have shown promise in the treatment of ME. Dexamethasone, a more potent corticosteroid than triamcinolone, has been shown to produce high intra-vitreal levels of the drug, however, a short intra-ocular half-life after intra-vitreal injection (approximately 3 hours) has led to the investigation of other delivery methods.
The following reactions have been identified during post-marketing use of OZURDEX® in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. The reactions, which have been chosen for inclusion due to either their seriousness, frequency of reporting, possible causal connection to OZURDEX® , or a combination of these factors, include: complication of device insertion ( implant misplacement), device dislocation with or without corneal edema, endophthalmitis, hypotony of the eye (associated with vitreous leakage due to injection), and retinal detachment .