In which cases of post-injection endophthalmitis should early vitrectomy be considered if there is little to no improvement 48 hours after a tap and inject and there is no organism isolated?  

Prompt vitrectomy should be considered in all patients with post-injection endophthalmitis (PIE) if there is no improvement 48 hrs after a tap and inject. The initial tap did not identify the organism. Non-infectious endophthalmitis can be included in the differential diagnosis of persistent inflamm...

While I agree with my colleagues above, I feel compelled to point out several observations I have made over the years. There really isn't any great data along the lines of the EVS for post-injection endophthalmitis. Post-injection endophthalmitis is by far more common as a percentage than post-sur...

Yes. Sometimes a vitrectomy is helpful to debulk the infection and allow the antibiotics to spread through the vitreous cavity. I only do a core vitrectomy in these cases, as the retina can be quite friable, and attempting to lift the hyaloid can cause a detachment or tear.

Yes. Sometimes a vitrectomy is needed to clear the toxins and just the vitreous opacities. Debulking the vitreous allows better penetration of the antibiotics and will often help get rid of plaques of bacteria stuck to the lens (natural or IOL).