Disclosed are biodegradable microspheres between 40 µm and 200 µm in diameter that are effectively retained in the anterior chamber of the eye without producing hyperemia. The microspheres generally contain a drug effective for the treatment of an ocular condition and include a biodegradable polymer matrix that can provide for the sustained (>；7 day) release of the drug following administration to the anterior chamber of the eye. Methods for making and using the microspheres to treat an ocular condition are also disclosed.
