Macular edema natural history

The natural history of macular edema due to CRVO was also delineated in the CVOS (2-4). One hundred and fifty-five group M eyes (77 treated eyes and 78 control eyes) were followed over a three-year period. All eyes had macular edema for a minimum of three months prior to enrollment (4). For untreated eyes with... 

The CYOS demonstrated that the natural history of untreated macular edema is poor in many patients. Additionally, the CYOS showed that grid laser photocoagulation for macular edema does not improve visual acuity compared with the natural history of this disease. Therefore, it is important to explore other avenues for managing this common cause of vision loss. 

Table 1 Natural History of Macular Edema Due to Retinal Vein Occlusion in Randomized Trials...

The BVOS also reported on the natural history of macular edema due to BRVO (1). After three years, of 35 untreated eyes available for follow-up, only 12 eyes (34%) with a presenting visual acuity of 20/40 or worse achieved a visual acuity of 20/40 or better. Furthermore, eight eyes (23%) had 20/200 or worse visual acuity at their final three-year follow-up visit. 

As in the management for CRVO, the purpose of such a procedure is to reestablish venous outflow by creating a chorioretinal anastomosis distal to the site of obstruction, to attempt to improve visual acuity by decreasing macular edema, and to decrease the conversion from nonischemic to ischemic vein occlusion. Fekrat and de Juan (77) reported on six eyes with branch vein occlusion of whom, three had successful anastomoses. Of the six eyes, the visual acuity improved one to three lines in two, remained unchanged in one, and decreased in three. This result does not appear to be significantly better than the natural history of visual acuity loss due to BRVO. 

---