Influence of drug solubility and lipophilicity on transscleral retinal delivery of six corticosteroids.
To determine whether a posterior sub-Tenon injection of triamcinolone acetonide (TA) before focal photocoagulation is safe and effective in patients with diabetic macular edema. Sixteen eyes of 11 diabetic patients with unresolved diffuse macular edema were treated with a 20-mg sub-Tenon injection of TA 1 to 2 months before focal photocoagulation. Focal photocoagulation was applied only to microaneurysms, and grid laser photocoagulation was not performed. The main outcome measures used were visual acuity (VA), central macular thickness (CMT) determined by optical coherence tomography (OCT), and the fluorescein angiographic appearance of the retina. Patients were followed for at least 6 months. One month after the sub-Tenon injection of TA, the macular edema was resolved with a significant reduction of the CMT on OCT. VA improved slightly. Subsequent focal photocoagulation of the microaneurysms maintained the significant reduction of CMT for up to 6 months. A significant improvement of VA was observed in 37.5% patients at 6 months, and there was no decrease in VA in any of the patients. A 20-mg sub-Tenon TA injection prior to focal laser photocoagulation is a safe and beneficial treatment in patients with diabetic macular edema.