Retinal vein occlusions are common retinal vascular disorders, often complicated by cystoid macular oedema ( CMO). The present report describes morphological and functional changes associated with an intravitreal injection of triamcinolone acetonide (TA). Patient 1 was a 75-year-old woman with CMO due to a macular branch vein occlusion 2 years previously. Visual acuity (VA) was reduced to 0.25. Preoperative optical coherence tomography (OCT) and fluorescein angiography ( FA) showed a CMO with macular thickening to about 400 mm ( Figs 1 and 2). Having given informed consent, the patient was treated with an intravitreal injection of 25 mg TA. Five weeks after the injection, the oedema had almost completely resolved and the retina had flattened to 210 mm with the foveal depression visible again ( Fig. 3). Fluorescein angiography showed a pronounced reduction in fluorescein leakage ( Fig. 4) and VA had increased to 0.5. Patient 2 was a 71-year-old man who had experienced a central retinal vein occlusion 8 months previously. Optical coherence tomography and FA showed an extensive CMO ( Figs 5 and 6). Visual acuity was reduced to 0.4. Five weeks after an injection of 25 mg TA, foveal thickness had decreased from more than 600 mm preoperatively to 200 mm, and the fovea showed an almost normal central depression ( Fig. 7). Fluorescein leakage was also markedly reduced ( Fig. 8). Visual acuity increased to 0.5. For many patients who suffer cystoid macular oedema after central or branch retinal vein occlusion, and who are either not eligible for or are resistant to laser coagulation, no satisfactory treatment options are yet available. During the last 2 years the intravitreal use of triamcinolone acetonide for various forms of macular oedema has been reported increasingly ( Antcliff et al. 2001; Jonas Sofker 2001; Jonas et al. 2001; Greenberg et al. 2002). The present report shows that intravitreal TA, without additional laser coagulation of the retina, can be associated with a decrease in or resolution of CMO, a reduction of foveal thickening by more than 50%, and a corresponding increase in central visual acuity.