There are a lot of risks with retroviral genetic therapy. However, there are a lot of upsides. I think what we need most, is to gain as much knowledge as possible, to ensure we can treat anything untoward as a result.

In terms of 'leaving the local area', there was a recent treatment intended to be done on one eye first, just in case it did not go as planned. It spread to the other eye:

https://www.cam.ac.uk/research/news/gene-therapy-injection-i...

Viral vector DNA was detected in the anterior segment, retina and optic nerve of the untreated eye. The unexpected visual improvement observed in the untreated eyes could therefore reflect the interocular diffusion of rAAV2/2-ND4. Further investigations are needed to confirm these findings and whether other mechanisms are contributing to this bilateral improvement.

Seeing as the eye was directly injected, it's unclear how it spread. Blood, likely.

Yes, some of the vector was likely cleared from the AH and exposed the contra lateral eye