This chapter addresses infections associated with artificial devices of a specialized nature. The rate of infection is generally low, but collectively, there are millions of these devices implanted yearly, so the infections are not rare. Optimal treatment requires participation of surgical specialists experienced in the management of these difficult infections, especially for pseudophakic endophthalmitis, in which therapy includes intraocular injections.

Intraocular lens-associated infections (pseudophakic endophthalmitis)

Pseudophakic endophthalmitis is thought to occur as a consequence of contamination with flora of conjunctival sac or lid margin at the time of surgery. There also have been reports of infections arising from contamination of lenses and neutralizing and storage solutions.

The differential diagnosis of endophthalmitis following cataract extraction includes sterile inflammation as well as bacterial and fungal infection. The most common presenting signs and symptoms include pain in the involved eye, decreased visual acuity, red eye, lid edema, hypopyon, and absent or poor red reflex. A single bacterial strain is usually isolated; the most common pathogen is a coagulase-negative staphylococcus (approximately 50% in one large series) followed by Staphylococcus aureus. Virtually any microorganism can be implicated. Delayed onset pseudophakic endophthalmitis has been reported after uncomplicated initial cataract surgery. This entity presents one or more months after surgery and is manifest by waxing and waning ocular inflammation. The leading cause of delayed-onset pseudophakic endophthalmitis is Propionibacterium acnes. Diagnostic evaluation requires aqueous and vitreous samples for Gram stain and culture. Vitrectomy may have therapeutic as well as diagnostic value.