This study will consist of 2 parts: Part 1 is an open-label, sequential dose escalation part to determine the Dose Limiting Toxicities (DLTs) and Maximum Tolerated Dose (MTD) of TLC399 (ProDex) in patients with macular edema due to central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO). Part 2 is a randomized, single-masked part of the study designed to investigate the use of TLC399 (ProDex) in patients with macular edema due to central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO). Each of the 3 groups will have a maximum of 10 subjects, adding Part 1 and Part 2.