Bacterial Scleral Abscesses after Retinal Buckling Operations: Pathogenesis, Management, and Laboratory Investigations

Abstract

Between 1971 and 1985, 28 patients were treated for a scleral abscess after a scleral buckle procedure. Twenty-six of the patients had the original surgery performed between those years during which a total of 4480 buckling procedures were performed. Therefore, the incidence of scleral abscess after buckling procedures was 0.58% (26/4480). All 28 patients had excessive pain, conjunctival chemosis and proptosis, a creamy white area of retina on the buckle, and a variable amount of vitreous inflammation. Seventeen of these patients had an especially severe scleral abscess with inflammatory vitreous opacification, which precluded visualization of the retinal vessels or allowed at most a hazy view of the optic nervehead or the scleral buckle. A review of these 17 severely involved patients showed that, in most cases (13 of 17), the vitreous inflammation was sterile. Therefore, most patients can be managed simply with immediate removal of the buckle along with topical and systemic antibiotics. A laboratory investigation showed that a cell-free millipore filtrate of Staphylococcus aureus culture in trypticase soy broth caused prominent but self-limited inflammation when injected intravitreally. Therefore, bacterial toxins or secretions could be the cause of the prominent vitreous inflammation in most patients with scleral abscesses. In another experiment, sponge exoplants, which had been soaked in a highly concentrated culture of S. aureus, were sutured episclerally in rabbits. A scleral abscess developed in 19 of 23 rabbit eyes with these infective sponges. Progressive scleral abscesses, which closely resembled those seen in humans, developed in 14 of the 23 eyes. Cultures of the vitreous were performed after opening the eyes so that contamination would not occur as the needle passed through the infected ocular coats. Nine of the 14 eyes had positive vitreous cultures relatively early on even when the vitreous cavity was only moderately inflamed. Therefore, the S. aureus in this in vivo model of an infective sponge exoplant penetrated the thin rabbit sclera readily.