To evaluate the natural course of eyes with decreased visual acuity associated with macular edema secondary to branch retinal vein occlusion (BRVO) and to compare the visual outcome and macular thickness with those of eyes treated with intravitreal triamcinolone acetonide injection (IVTA).

We reviewed the medical records of patients with macular edema secondary to BRVO who were followed-up for 12 months. We evaluated the best corrected visual acuity (BCVA) and macular thickness of the patients who had no treatment for macular edema (natural course group) and compared them with those of patients who had been treated with IVTA (treatment group).

A total of 29 eyes (29 patients) in the natural course group and 27 eyes (27 patients) in the treatment group were enrolled. The BCVA of the natural course group improved in a slow but steady manner and showed a statistically significant difference at 12 months. The treatment group did not show any improvement in BCVA throughout the follow-up period. Therefore, BCVA significantly improved in the natural course group after six months compared to that in the treatment group. Macular thickness showed a statistically significant reduction in three months in the natural course group and in one month in the treatment group.

Although IVTA was effective in reducing macular edema in branch retinal vein occlusion at one month after administration, the natural course group had a superior outcome and more improved macular thickness after six months.