My father was a long-time diabetic and suffered from retinopathy. What we know now about diabetes management and valid forms of treatment for retinopathy is far greater now than back in my father's day (20-30 years ago). He underwent a series of vitrectomies, which worked to combat the damaged vision for a while. But, eventually, it was not possible to compensate for the continuing damage with those treatments.
I don't say that to be a "downer". As mbuster stated, it may not be possible to reverse the damage but it may be possible to prevent more damage from occurring, by getting your blood glucose under tighter control.
Please check out the Bloodsugar101 Web site and consider how a vegetarian diet could fit into that approach to managing blood glucose. And feel free to ask questions here. There are members of this forum who limit their meat or dairy or egg consumption and might be able to provide some support for your goals.