8. Treatment
The damage caused by these infections can be severe and irreversible. White blood cells have no direct access to the vitreous cavity as it is an avascular space, and thus injury most often leads to scar rather than repair. Furthermore, functional loss occurs as a result of not only the damage caused by the infection, but also the associated inflammation. If this damage involves the retina, permanent visual loss may occur and thus treatment of postoperative endophthalmitis should be initiated as soon as possible. The EVS was conducted because there was no standardized evidence as to the optimal treatment of eyes with postoperative endophthalmitis. Some thought that early surgery would be beneficial in eliminating organisms as well as inflammation from the eye. Others thought that surgery would cause more damage in an inflamed eye. In addition, the role of intravenous antibacterials in the treatment of postoperative endophthalmitis was unclear. The EVS randomized patients to one of two standard treatment strategies for the management of bacterial endophthalmitis. Eyes received either initial pars plana vitrectomy (PPV) with intravitreal antibacterials or initial injection of intravitreal antibacterials. The study showed that in patients who presented with the most severe visual loss, light perception vision, an emergent vitrectomy is the treatment of choice, leading to superior final visual outcomes. In patients with light perception vision, vitrectomy produced a 3-fold increase in the frequency of achieving 20/40 or better acuity (33% vs 11%). In patients with vision of hand motions or better, there was no difference in outcome whether or not they received an immediate vitrectomy. The most effective treatment seemed to stem from the direct injection of antibacterials into the vitreous cavity. The antibacterials used for intravitreal injection were amikacin (0.4mg in 0.1mL) and vancomycin