Immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin. A rabbit experimental model

PURPOSE Acute retinal toxicity secondary to inadvertent intracameral injection of massive doses of gentamicin is a devastating complication of cataract surgery, for which no treatment, to date, either surgical or medical, has been shown to be effective. A rabbit experimental model was used to examine the effect of immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin. METHODS Twenty-seven rabbit eyes were subjected to lensectomy with or without preservation of the lens capsule. Aphakic rabbit eyes and rabbit eyes with an intact lens capsule were then subjected to injections of massive doses (4 mg and 20 mg) of gentamicin into the anterior chamber. Experimental eyes underwent an immediate pars plana vitrectomy and posterior segment lavage. The rabbits were killed after 7 days. Light microscopic examination was then performed to ascertain the degree of retinal damage caused by the injection. RESULTS Rabbit eyes receiving immediate pars plana vitrectomy exhibited far less structural damage to the retina, as seen by light microscopy, than did corresponding control eyes. Furthermore, there appeared to be a protective effect of an intact lens capsule with regard to retinal damage. CONCLUSIONS Immediate pars plana vitrectomy and posterior segment lavage may alleviate the effects of intracameral injection of gentamicin. This preliminary study demonstrates the need to perform further studies with a vascularized primate retina to evaluate immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin.