Intravitreal triamcinolone acetonide for diabetic retinopathy

Abstract

Intravitreal triamcinolone acetonide (IVTA) has been applied in exponentially increasing frequency for various intraocular neovascular and edematous diseases, including diabetic macular edema, proliferating diabetic retinopathy, neovascular glaucoma due to proliferative diabetic retinopathy, and chronic prephthisical ocular hypotony as complication of the surgical treatment of diabetic retinopathy. In diabetic macular edema, the edema may almost completely resolve, and visual acuity may increase as much as macular ischemia and the tissue destruction by the diabetic process may allow. For proliferative diabetic retinopathy and neovascular glaucoma, investigations have suggested an antiangiogenic effect of IVTA. Using a side effect of IVTA, i.e. steroid-induced elevation of intraocular pressure, IVTA may be applied for the therapy of chronic prephthisical ocular hypotony due to an insufficiency of the ciliary body as consequence of a surgical treatment of proliferative diabetic retinopathy. The complications of IVTA include secondary ocular hypertension in about 40% of the eyes, medically uncontrollable high intraocular pressure leading to antiglaucomatous surgery in about 1-2%, posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20%, especially in elderly patients within 1 year after injection, postoperative infectious endophthalmitis with a rate of about 1:500 or 1:1,000, noninfectious endophthalmitis, and pseudo-endophthalmitis. IVTA can be combined with other intraocular surgeries including cataract surgery, particularly in eyes with iris neovascularization due to diabetic retinopathy. Cataract surgery performed some months after the injection does not show a markedly elevated rate of complications. If vision increases and eventually decreases after an IVTA injection, the injection can be repeated. The duration of the effect of a single IVTA is dosage dependent (about 6-9 months with 20 mg, and about 2-4 months with 4 mg).