Intravitreal steroids for macular edema: the past, the present, and the future.

Macular edema, a condition usually associated with an underlying disease process, is a common cause of severe visual loss. There have been a variety of approaches to the treatment of macular edema; within the past few years, however, intravitreal corticosteroid treatments have emerged as an increasingly used treatment option for patients with macular edema. Intravitreal delivery allows the steroid to bypass the blood-retinal barrier, leading to a more concentrated dose of steroid for a prolonged period of time. Corticosteroids have likely been successful in the treatment of various forms of macular edema, due to their known anti-angiogenic, anti-edematous, anti-inflammatory, anti-apoptotic, and anti-proliferative effects. Intravitreal triamcinolone acetonide has been repeatedly successful in reducing macular edema and improving visual acuity, although the duration of action is typically short-term. Due to the recurrent and chronic nature of macular edema, biodegradable implants may be the future of intravitreal steroids. Intravitreal corticosteroids are not without risks. Steroid-related side effects include cataract formation and elevated intraocular pressure. Injection-related side effects include retinal detachment, vitreous hemorrhage, bacterial endophthalmitis, and sterile endophthalmitis. This article reviews the evolving role of intravitreal corticosteroids in the treatment of macular edema secondary to uveitis, diabetes, and retinal vascular disorders.