Persian post eye surgery issue

Hi,

I have a 4 year old Persian cat who was diagnosed with congenital abnormalities of the left eyeball. The vet recommended and performed eye surgery. 1.5 month after, the recovery is not going well and she started to have a black spot in the center of the eye. The vet doesn’t know what it is and requested the advice of an eye specialist. We are waiting for his / her opinion. Did anybody have that before (attached is a picture)? I am worried we might have to close permanently the eye.

Thanks.

Alex