Anterior chamber aspirate cultures in small incision cataract surgery.

Abstract

Background-Anterior chamber aspirates on completion of extracapsular cataract surgery contain significant numbers of organisms, particularly coagulase negative staphylococci, an important cause of endophthalmitis. Methods-Culture rates were compared in 50 patients after phacoemulsification surgery, which allows the possible benefits of a small, self sealing wound and maintenance of positive intraocular pressure, with a similar number of extracapsular cases.Results-A culture positive rate of 20% and 24% respectively was found, an insignificant difference. Conclusion-Small incision surgery has no proved advantage over extracapsular surgery in terms of reducing the intraoperative bacterial inoculum. The significance of this result in terms of causation of endophthalmitis is discussed. (Br_J Ophthalmol 1995; 79: 878-880) Recent studies by this and other groups have confirmed that the anterior chambers of eyes following extracapsular cataract surgery are frequently contaminated by small numbers of bacteria.1-3 Contamination rates of 29-43% have been reported. This group found a rate of 24% in two groups of 40 patients, and that preoperative topical antibiotics (norfloxacin, MSD) had no effect on culture rates. The organisms found are in small numbers (10-40 colony forming units/ml), and are most commonly skin commensals, especially coagulase negative staphylococci. These organisms are a leading cause of endophthalmitis. It has been assumed that one route of entry is from fluid circulating in the conjunctival sac at the time of surgery, but although both povidone-iodine4 5 and topical antibiotics6 are effective in reducing skin commensals (as shown by conjunctival swabs), efforts to sterilise the conjunctival sac preoperatively are only one approach to the problem, and according to our previous work may not be reducing intraocular contamination.Phacoemulsification allows a smaller wound, and is usually combined with a scleral tunnel which has a degree of self sealing properties. The eye is, therefore, less accessible to contamination from any external source, be it conjunctiva, lashes, or air. Studies of intraoperative pressure changes do suggest that positive intraocular pressure is easier to maintain with this type of wound,7 and this, together with the small wound, should minimise influx of conjunctival fluid from the wound margins.This study has been designed to examine the contamination of anterior chambers of eyes at the completion of phacoemulsification cataract surgery, and to compare this with previous observations from extracapsular surgery. Materials and methodsFifty patients undergoing routine phacoemulsification cataract surgery were recruited into this prospective study. Written consent for aqueous samples to be taken was obtained. Exclusion criteria included: (a) history or evidence of previous surgery or penetrating injury to the eye; (b) local or systemic infection at the time of surgery; (c) perioperative complications such as posterior capsule rupture or conversion to extracapsular surger...

Contribution of secreted proteases to the pathogenesis of postoperative Enterococcus faecalis endophthalmitis

“…Rupture of the posterior capsule during surgery is associated with a significantly higher incidence of postoperative endophthalmitis because aqueous humor contaminants can readily access the vitreous cavity. [10][11][12][13] However, the development of postoperative endophthalmitis in patients who have surgery without major intraoperative complications is a mystery. 15,16 Some investigators report that cataract surgery without posterior capsule rupture does not allow substances in the aqueous humor to move into the vitreous cavity because the posterior capsule 21,22 and anterior vitreous membrane 23 form a firm barrier.…”

“…It is unknown where they colonize and how they translocate through the posterior capsule to cause ocular tissue damage. Bacteria have a chance to enter the anterior chamber through the surgical wound, and many studies [10][11][12][13] report contamination of the anterior chamber at the end of surgery to be as high as 5.7% to 21.1%. Thus, intraoperative or postoperative contamination of the anterior chamber seems to be the initial step of endophthalmitis.…”

Sutureless Ophthalmic Surgery: A Scaffold-Enhanced Bioadhesive Technique

“…However, even "self-sealing" scleral and corneal incisions are not completely watertight and have been associated with endophthalmitis and traumatic rupture during the early postoperative period. 8,9 A wound-closure technique using a bioadhesive would eliminate the need for needles and sutures. At this time, the only bioadhesive in routine clinical ophthalmic use is cyanoacrylate for corneal perforations.…”

Presumed infectious endophthalmitis following cataract surgery in the UK: a case–control study of risk factors

“…Subconjunctival cefuroxime achieves therapeutic levels in the anterior chamber within 12-24 min of administration and maintains clinically significant levels for up to 12 h. 17,18 Postoperative therapeutic antibiotic levels within the anterior chamber will help to counteract the potential bacterial load in the eye as bacteria are present in the anterior chamber at the end of cataract surgery in 13-43% of patients. [19][20][21] There are some limitations to this study. Case ascertainment was questionnaire-based and dependent on voluntary reporting by ophthalmologists throughout the UK.…”