Because the macula—the part of the retina responsible for central vision—is affected by blocked veins, some central vision is lost.
The most common symptom of BRVO is vision loss or blurring in part or all of one eye. The vision loss or blurring is painless and may happen suddenly or become worse over several hours or days. Sometimes there is a sudden and complete loss of vision. BRVO almost always happens only in one eye.