To compare the effect of single intravitreal injection of triamcinolone acetonide and bevacizumab for the treatment of diabetic macular edema by optical coherence tomography (OCT) patterns.

We classified diabetic macular edema by three OCT patterns: Type 1, diffuse retinal thickening; Type 2, increased retinal thickness associated with the presence of intraretinal cystoid spaces (cystoid spaces with horizontal diameter >300 µm); and Type 3, serous macular detachment. According to this classification, 84 eyes of 42 patients with bilateral diabetic macular edema by the same OCT pattern participated in this study.In each patient,one eye was treated with a single intravitreal injection of bevacizumab 1.25 mg/0.05 ml (IVBI group) and the other eye with a single intravitreal injection of 4 mg/0.1 ml triamcinolone (IVTI group). A comprehensive ophthalmic examination was performed at baseline and at one, three and six months after treatment. Main outcome measures included best corrected visual acuity (logMAR) and central macular thickness measured with OCT.

In Type 1, central macular thickness (CMT) reduced significantly in the IVBI group at one month.In Type 2, mean BCVA and CMT improved significantly in the IVTA group at one and three months and in the IVBI group at one month following treatment. In Type 3, CMT reduced significantly in both groups at one, three and six months.However, BCVA did not significantly increase in either group at one, three or six months after treatment.

The effects of one single intravitreal injection of triamcinolone and bevacizumab differ by OCT patterns in bilateral diabetic macular edema patients.The correct therapeutic method, depending on OCT patterns of macular edema, should result in better improvement of visual acuity.