The basic parameter are: 1. How much does it bother you. If you are 20/25 and an airline pilot and are going to lose your job that might justify proceeding, if you are 20/50 functioning well and it doesn't bother you not much case to proceed. 2. If there is high grade traction on the macula and the risk of a full thickness hole is significant then surgery is usually recommended. Most ERMs are mild and do not need surgery.