Mechanical Retinal Vascular Obstruction (from Injections)
Mechanical retinal vascular obstruction may occur in the course of ocular surgery from an injection into the optic nerve sheath during anesthesia. Complications range from a retrobulbar hemorrhage with elevation of the intraocular pressure and/or a sudden rise in the intraocular pressure during the course of a closed vitrectomy operation, with resultant central artery occlusion.
Optic Nerve Sheath Injection
Retrobulbar Hemorrhage
Antibiotic Toxicity During Intraocular Surgery
Aminoglycoside toxicity is an uncommon though well-known clinical entity in intraocular surgery. When administered intravitreally, the toxic effect will depend up on the concentration and dose of the drug. Injection into the anterior chamber may also cause prominent uveitis with associated iris complications. Intraocular usage of gentamicin has become quite limited over the past 15 to 20 years. More recently, intracameral vancomycin has been shown to produce an apparent immune-mediated retinal vasculitis, with profound visual impairment. While this has only occurred in a very small number of patients, the precise etiology of this reaction is not entirely clear.
Intraocular Aminoglycosides
When the vitreous is intact, the effect is generally concentrated in a localized area of the posterior pole. The drug can diffusely spread throughout the posterior segment after a vitrectomy procedure. Following resolution of the acute toxic effect of the retina and the associated obliteration of the circulation, there is seldom any reperfusion.
Intracameral Vancomycin
Decompression Retinopathy
Decompression retinopathy results from a sudden drop in intraocular pressure. It is usually a complication of glaucoma surgery such as trabeculectomy, which is performed under either local or general anesthesia. Hemorrhages, both deep and superficial, may be seen in the posterior segment or diffusely throughout the fundus. There is no venous tortuosity or increased transit time, distinguishing this hemorrhagic event from venous occlusive disease.