Blood clot in posterior to the retina due to blunt injury to the eye with loss of vission. Pls tell me if the vision comes back or not?

Depends. Depends on the severity of the hemorrhage. As an oculoplastc specialist i deal with blunt trauma all the time but i leave the retina issues to a retinal specialist and concern myself with the bones. Hopefully one of the excellent retinal specialists on this forum will answer. As a general rule, the longer the vision remains poor and is not improving, the poorer the prognosis.
Depends. Post traumatic hemorrhage of the retina can be catastrophic when the bleeding occurs underneath the retina. Bleeding in the vitreous cavity is least dangerous and can also arise from trauma. So, the most important factor is where the blood clot is. Under the retina is least likely to come back. Exam and oct can often sort this out.