Can endophthalmitis be prevented?

Abstract

In 2002, Per Montan and co-workers at St Erik Eye Hospital in Stockholm, Sweden, published two articles, a safety study and an efficacy study (Montan et al. 2002a; Montan et al. 2002b), on intracameral cefuroxime as prophylaxis against endophthalmitis in cataract surgery. In brief, they showed that 1 mg of cefuroxime injected in the anterior chamber was safe and reduced the number of endophthalmitis cases. The Montan group had 2 years previously reported these findings to Swedish cataract surgeons, who promptly adopted this procedure. The effect was soon seen in a reduced endophthalmitis rate in Sweden. The incidence of endophthalmitis in Sweden has been followed through the National Cataract Register, and several publications have resulted (Montan et al. 2002c; Lundström et al. 2007; Friling et al. 2013). The European Society for Cataract and Refractive Surgeons (ESCRS) adopted the Montan concept soon after and carried out the first and so far only prospective randomized trial, in which they demonstrated that intracameral antibiotic reduced the number of endophthalmitis cases (Barry et al. 2006). The procedure has since then received international recognition and is the standard technique in many countries although with varying utilization rates. Several national societies recommend their members to use intracameral antibiotic in every case, and there are even government departments that do the same (personal communication, Peter Barry). One question still under debate is which antibiotic to use. In the literature, cefuroxime and moxifloxacine are most commonly used. Both were for some years prepared for injection by a procedure sometimes referred to as ‘kitchen pharmacy’, that is no ready-made and ready-to-use solutions were available. Therefore, the possibilities of dilution errors have been pointed out as a possible complication risk. Recently, cefuroxime has been available in a commercial, single-use preparation, taking the risk of incorrect concentration out of the question. This debate is certain to go on. In this issue, Kessel, Flesner, Sandresen, Erngaard, Tendal and Hjortdal have undertaken the immense work of reviewing the world literature on the topic and produced a meta-analysis on prevention of endophthalmitis in cataract surgery. This deserves a careful read. Cataract surgery, the most frequent ophthalmic surgery, is not the only procedure that is troubled by endophthalmitis. Penetrating keratoplasty has the same problem, and the frequency here is more than ten times as high. In corneal surgery, no standardized prophylactic treatment has been adopted as in cataract surgery. One further difference is that corneal transplantation is sometimes carried out on sick and high-risk eyes. Endophthalmitis is also a feared complication in antivascular endothelial growth factor (VEGF) injections. This treatment modality was introduced in 2007, and the number of treatments has increased rapidly. In Sweden alone, more than 30 000 injections were performed in 2014 (personal communication, Inger Westborg). In the annual report from the Swedish Macular Register, it can be seen that the incidence of endophthalmitis in anti-VEGF injections is 0.026%, which is very close to the incidence in cataract surgery with intracameral antibiotic. Cataract surgery is performed once, but anti-VEGF injections are given repeatedly, which increases the incidence for each patient. Furthermore, in anti-VEGF injections, there is no standard of treatment or prophylactic strategies. A number of questions need to be addressed: What is the role for antibiotics? Is pre- and/or postoperative treatment to be recommended, or will antibiotics change the bacterial flora of the conjunctiva in favour of an infection? Should the procedure be performed in an operating suite or is a ‘clean room’ good enough? How should the eye to be injected be prepared and for how long should the eye be exposed to povidone-iodide or chlorhexidine before the injection is carried out? The Swedish Macular Register is collecting data on all these issues, which will most probably give an indication on how a prospective, randomized trial should be set-up. Additionally, the ESCRS recently started an international Endophthalmitis Register to study this complication both after cataract surgery and anti-VEGF injections. This register can be accessed at www.ESCRS.org. Ideally, each anti-VEGF-injected patient should be pretreated with a substance that would sterilize the conjunctival surface for the time of injection without causing changes in the resistant patterns of the bacterial flora. To date, such a substance is not known.