May be normal. Retinal surgery can leave some vision loss while it repairs a larger problem. Often, the remaining damage to the vision is much smaller than had no treatment been instituted. If the shadow area has become larger or your vision has decreased since the surgery, see your retina specialist immediately.
Not uncommon. Major causes of "shadow area after retinal surgery": 1. Area where the retina was detached and irreparably damaged. 2. Area where the eye needed to be treated by laser or cryo to enable the retina to adhere. 3. Residual fluid after surgery. 4. Residual gas bubble after surgery. 5. Scar tissue. 6. Inflammation or edema. Examination needed to determine which.