Biocompatible intraocular microspheres and implants include an alpha-2 adrenergic receptor agonist and a polymer associated with the alpha-2 adrenergic receptor agonist to facilitate release of the alpha-2 adrenergic receptor agonist into an eye for an extended period of time. The alpha-2 adrenergic receptor agonist may be associated with a biodegradable polymer matrix, such as a matrix of a two biodegradable polymers. The implants may be placed in an eye to treat or to prevent the occurrence of one or more ocular conditions, to reduce one or more symptoms of an ocular condition, such as an ocular neurosensory disorder and the like, to enhance normal retinal function and/or to lower intraocular pressure.