IOL Biofilms and Fluids After Uncomplicated Cataract Surgery
American Journal of Ophthalmology, September 2016
Mazoteras et al. performed a laboratory investigation to evaluate the intraocular environment, capsular tissue, and intraocular lens (IOL) surfaces in normal eyes after uncomplicated cataract surgery; the aim of the study was to better understand the mechanisms of endophthalmitis that may occur long after surgery. Although none of the eyes had a reported history of intraocular inflammation, the authors found pathogenic biofilms adhering to the IOLs in many cases.
The researchers studied 69 eyes that had been donated for transplantation (but were deemed unsuitable for keratoplasty), which had previously undergone cataract surgery with posterior chamber IOL implantation without a clinical history of postoperative inflammation. They performed microbiologic evaluation of fluid from the anterior and posterior chambers and scanning electron microscopy (SEM) to assess the IOL surfaces.
SEM revealed evidence of cellular epithelial aggregates and crystalline fiber remnants on most of the IOLs examined, and isolated or aggregated cocci were also observed on 18.8% of the IOLs. These findings suggest the presence of a microorganism biofilm colonizing the surface of the IOL, despite the absence of symptoms or reported episodes of intraocular inflammation. When analyzed by conventional microbiological techniques, intraocular fluid samples did not show evidence of microbial growth; when subjected to DNA amplification, 2 samples revealed bacterial DNA, although the authors noted that the microorganisms might have been introduced during processing.
The authors stated that in other studies, bacteria were present in 0%-46% of the aqueous humor aspirates taken perioperatively but that the reported incidence of endophthalmitis is very low, at 0.05%-0.34%. They posit that several mechanisms combine to prevent development of intraocular inflammation, even when bacteria are present, including low inoculum or low virulence of the microorganisms or poor adherence to polymer surfaces. Thus, in this setting, the patient’s immune response is usually adequate to overcome possible infections in the early phases, and an intact posterior capsule provides further protection. In addition, postoperative topical steroids and antibiotics reduce the likelihood of endophthalmitis. The authors concluded that more study of the postoperative intraocular environment is needed to determine the factors that suppress or promote the development of endophthalmitis.
The original article can be found here.