Prevention of postcataract endophthalmitis: evidence-based medicine

Inflammatory Complications of Intravitreal Anti-VEGF Injections

Intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents is a commonly used therapy for numerous retinal diseases. The most commonly used of these medications are bevacizumab, ranibizumab, aflibercept, and brolucizumab. However, intravitreal administration of these agents is also associated with several inflammatory and non-inflammatory adverse events. The three inflammatory adverse events are sterile intraocular inflammation, brolucizumab-associated retinal vasculitis, and post-injection endophthalmitis. This narrative review summarizes the current literature regarding these conditions, including their epidemiology, presentation, management, outcomes, and pathogenesis. The inflammatory adverse events also share a number of overlapping features, which can make them difficult to discern from one another in a clinical context. This review discusses certain distinguishing features of these conditions that may aid providers in discerning between them and establishing the correct diagnosis.

Drug Delivery Polymer Systems for Ophthalmic Administration of Anti- Viral Agents

BACKGROUND

Ophthalmology applies many different ways of delivering effective drugs to eye tissue for the prevention and treatment of diseases of various etiologies. The vast majority of ophthalmologists use traditional instillation of drugs in an eye disease. However, this method has a number of drawbacks, in particular, during instillation of drip forms of drugs, up to 80% of the drug is lost due to withdrawal of its tear fluid and rapid absorption by the mucous membrane of the eyes, which necessitates their frequent instillation to maintain the therapeutic concentration in the eyeball.

OBJECTIVE

The use of polymeric forms of bio soluble antiviral eye medicinal films of prolonged form in ophthalmic practice would allow introducing the active substance less often while maintaining its therapeutic concentration, reducing the dosage of the drug and the negative effect of frequent instillation.

METHODS

A method of obtaining polymeric forms of bio soluble nanostructured ophthalmic medicinal films is based on a composition of water-soluble Na-carboxymethylcellulose (Na-CMC) with a degree of substitution of 0.85 ± 2 and a polymerization degree of 630 ± 20 and a derivative of Nacarboxymethylcellulose containing a chemically bound natural polyphenol-gossypol in an amount of polymerization-630 ± 20 and a derivative of Na-carboxymethylcellulose containing chemically bound natural polyphenol-gossypol in an amount of 0 mole% (sodium salt of 2,3-diethoxy - 6 - O - carboxymethyl- (1 → 4) -β - D - ox glucose - oxy-hydroxyl - 2 - ethyl- (1 → 4) -β - D - ox glucose - diethyl hydroxyl-poly -2 - O - carboxymethyl- (1 → 4) - β - D glucose -2.6 - O -dicarboxymethyl- (1 → 4) -β - D glucose); this is the substance of the antiviral drug "CelAgrip".

RESULT

In this work the possibility of regulating the bio scission time and physicochemical parameters of ocular medicinal films has been shown, by varying the degree of substitution and degree of polymerization of sodium carboxymethylcellulose and the pH of their aqueous solutions.

CONCLUSION

The most promising in terms of the prolongation effect and the absence of an irritating effect and transparency are films, obtained from solutions of the polymer-polymer composition of Na- CMC - a "CelAgrip" substance of a spherical shape with embedded nanoparticles of size 14-52 nm and a pH value of 7.6.

Role of topical antibiotics in prophylaxis against endophthalmitis following intravitreal antibiotics

Objective:

To compare the prophylactic use of antibiotic with placebo to prevent post intra-vitreal endophthalmitis and other complications.

Methods:

A prospective, cohort study was conducted at Ophthalmology Department, Fauji Foundation Hospital (FFH), from June 2016 to July 2017. A total of 1082 eyes of 673 patients were enrolled in this study. Patients were selected at non-random and divided into two groups. In Group-I, non – exposed, placebo eye drops were given after intravitreal bevacizumab injections and in Group-II, exposed, ofloxacin eye drops were given after intravitreal bevacizumab injections.

Results:

Total 1082 eyes were given intravitreal bevacizumab injection in 673 patients. No patients in Group-I, non – exposed, receiving placebo eye drops developed post intra vitreal endophthalmitis, whereas only 01 (0.1%) patient developed post intravitreal endophthalmitis in Group-II, exposed, receiving ofloxacin eye drops. In inferential statistics the P- value was also statistically insignificant [x² (1, N=1082) =0.95, P>0.05]

Conclusion:

This study showed that topical antibiotic, as a prophylaxis after intravitreal injections has no role in the prevention of post intravitreal endophthalmitis and other complications.

Endophthalmitis Prophylaxis for Cataract Surgery

Endophthalmitis after cataract surgery is a rare but potentially devastating complication. There is great variability in endophthalmitis prophylaxis practice patterns worldwide. Treatment varies globally and is based on the microbiological profile and availability of formulations. Periocular povidone-iodine antisepsis is universally adopted and considered the standard of care in most practices. Perioperative topical antibiotics are also very popular despite the lack of level 1 evidence confirming efficacy. Based on growing observational evidence, routine intracameral antibiotic prophylaxis is increasing, especially where approved commercial intraocular preparations are available. This review updates recent trends and evidence regarding endophthalmitis prophylaxis and the preferred choice of intracameral antibiotics.

Analysis of Intraocular Lens Biofilms and Fluids After Long-Term Uncomplicated Cataract Surgery

PURPOSE

Postoperative endophthalmitis is a potentially sight-threatening complication of cataract surgery. However, the pathophysiological mechanisms are not completely understood. We sought to study and evaluate the intraocular environment (aqueous and vitreous humors), the capsular tissue, and the intraocular lens (IOL) surfaces of normal eyes after long-term uncomplicated cataract surgery.

DESIGN

Experimental laboratory investigation.

METHODS

We studied 69 eyes donated for transplantation that had previously undergone cataract surgery with posterior chamber IOL implantation and that had no recorded clinical history of postoperative inflammation. We assessed the intraocular environment (DNA traces and biofilm formation) by microbiological evaluation of intraocular fluids using conventional microbiology and molecular techniques, including assessment for the presence of microbes (biofilm formation) on the IOL surface by scanning electron microscopy and ultrastructural capsular remnants by transmission electron microscopy.

RESULTS

Isolated or aggregated cocci were probable in 18.8% of IOL optic surfaces (n = 13) studied by scanning electron microscopy, suggesting the presence of bacterial biofilm. In 3 intraocular fluid samples for IOLs with biofilm, we identified 16S rDNA by polymerase chain reaction and sequencing. No microbial contamination was found in intraocular fluids by conventional microbiological methods.

CONCLUSIONS

Our data suggest the possibility of bacterial biofilm formation on the optic surface of IOLs in normal eyes after long-term uncomplicated cataract surgery even in the absence of clinical or subclinical symptoms.

Current Perspectives of Prophylaxis and Management of Acute Infective Endophthalmitis

Endophthalmitis is an intraocular inflammatory condition which may or may not be caused by infective agents. Noninfectious (sterile) endophthalmitis may be attributable to various causes including postoperative retained soft lens matter or toxicity following introduction of other agents into the eye. Infectious endophthalmitis is further subdivided into endogenous and exogenous. In endogenous endophthalmitis there is hematogenous spread of organisms from a distant source of infection whereas in exogenous endophthalmitis direct microbial inoculation may occur usually following ocular surgery or penetrating eye injury with or without intraocular foreign bodies. Acute infective endophthalmitis is usually exogenous induced by inoculation of pathogens following ocular surgery, open-globe injury and intravitreal injections. More infrequently the infective source is internal and septicemia spreads to the eye resulting in endogenous endophthalmitis. Several risk factors have been implicated including immunosuppression, ocular surface abnormalities, poor surgical wound construction, complicated cataract surgery with vitreous loss and certain types of intraocular lens. Comprehensive guidelines and recommendations on prophylaxis and monitoring of surgical cases have been proposed to minimize the risk of acute endophthalmitis. Early diagnosis and prompt management of infective endophthalmitis employing appropriately selected intravitreal antibiotics are essential to optimize visual outcome.

The Incidence of Postoperative Endophthalmitis Before and After a Revised Preoperative Surgical Site Preparation Protocol

PURPOSE

To compare the incidence of postoperative endophthalmitis before and after the implementation of a preoperative surgical site preparation protocol for cataract surgery.

DESIGN

Retrospective cohort study.

METHODS

Records of patients with postoperative endophthalmitis between January 2006 and August 2013 were reviewed. A revised protocol implemented after January 2009 included the addition of preoperative 0.3% topical tobramycin, 10% povidone-iodine for cleansing, and using a disposable sterile drape. The incidence, microbiological profile, and outcomes of these cases were analyzed.

RESULTS

The incidence of preprotocol endophthalmitis was significantly higher than in the postprotocol period (P = 0.018). More patients in the preprotocol group grew Pseudomonas aeruginosa and Streptococcus pneumoniae as compared with those in the postprotocol group (P = 0.014). A smaller number of patients attained a poor visual outcome after the implementation of the revised protocol (P = 0.035).

CONCLUSIONS

In our study, the addition of antibiotic eye drops before cataract surgery and perioperative cleansing with 10% povidone-iodine were effective means to reduce the incidence of postoperative endophthalmitis.

In vitro biofilm distribution on the intraocular lens surface of different biomaterials

PURPOSE

To study the disposition of bacterial adhesion to intraocular lens (IOL) biomaterials depending on the material and region of the optic IOL surface: center or peripheral edge.

SETTING

School of Medicine, University of Barcelona, Barcelona, Spain.

DESIGN

Experimental study.

METHODS

For the in vivo study, IOLs were explanted from donor ocular globes without clinical symptoms of endophthalmitis. Biofilm formation was qualitatively studied by scanning electron microscopy (SEM). For the in vitro study, 5 IOL biomaterials (hydrophilic acrylic, hydrophobic acrylic, poly[methyl methacrylate] [PMMA], heparinized PMMA, and silicone) were contaminated with a biofilm-producing strain of Staphylococcus epidermidis. Bacterial densities were quantitatively (colony-forming units per area) compared by SEM and direct counting of viable adherent bacteria, according to the biomaterial, region of the IOL optic surface, and time of incubation. For SEM, bacterial adhesion was also qualitatively classified according to the characteristics of biofilm observed: structure, cocci per cluster, homogeneity of cluster distribution, and extracellular matrix production.

RESULTS

At 3 hours of incubation, bacterial counts for hydrophilic acrylic and PMMA IOLs were significantly lower, but at 72 hours there were no statistically significant differences among biomaterials. A higher density of bacteria was observed at the periphery of the IOL's optic of assayed biomaterials for in vitro and in vivo studies. Biofilm formation and the presence of extracellular matrix were predominantly restricted to the edges of IOL optic surface.

CONCLUSION

Bacterial adhesion and biofilm development on the IOL optic surface depended on the region and biomaterial of the IOL.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Cohort study of intracameral moxifloxacin in postoperative endophthalmitis prophylaxis

We conducted a cohort study to evaluate post-cataract surgery endophthalmitis rates in relation to prophylactic intracameral moxifloxacin administration. A total of 2332 patients (2674 eyes) who underwent phacoemulsification by a single surgeon from January 2007 through December 2012 were included in the study. A total of 1056 eyes did not receive intracameral prophylactic moxifloxacin and the antibiotic was injected in 1618 eyes. The incidence of presumed postoperative endophthalmitis in the 2 groups was calculated. The rate of presumed infectious endophthalmitis after cataract surgery between January 2007 and June 2009 (without intracameral moxifloxacin) was 0.094%. The rate in the second period, from July 2009 to December 2012 (with prophylactic intracameral moxifloxacin), was 0%. In our patients, a decline in the incidence of presumed infectious postoperative endophthalmitis appeared to be associated with the application of intracameral moxifloxacin.

Ocular penetration and efficacy of levofloxacin using different drug-delivery techniques for the prevention of endophthalmitis in rabbit eyes with posterior capsule rupture

PURPOSE

To evaluate the effects of different drug-delivery techniques for levofloxacin (LVFX) in ocular penetration and the prevention of endophthalmitis using an aphakic rabbit model with posterior capsule rupture (PCR).

METHODS

LVFX was administered to aphakic rabbit eyes with or without PCR using eye drops (EDs), subconjunctival injection (SCI), or intracameral (IC) injection. The concentration of the drug in the vitreous and aqueous humors was estimated at 2 h after injection. In another study, aphakic rabbit eyes with PCR were inoculated with Enterococcus faecalis, immediately followed by 0.5% LVFX ED, 0.5% moxifloxacin (MFLX) ED, LVFX IC (500 μg/0.1 mL), or IC saline. EDs were administered 0, 3, and 6 h after surgery. Changes on electroretinography (ERG) and intraocular bacterial growth were determined sequentially until 48 h after inoculation.

RESULTS

The concentrations of LVFX at 2 h after IC were higher in the aqueous humor and the vitreous cavity of eyes with or without PCR, compared with EDs or SCI. Eyes treated with LVFX ED, MFLX ED, or IC saline showed a significantly greater reduction in b-wave amplitude on ERG at 48 h compared with eyes treated with LVFX IC. The number of bacteria recovered from the vitreous humor in eyes treated with IC LVFX at 48 h was significantly less than from eyes that received other treatments.

CONCLUSION

The LVFX IC was effective at suppressing endophthalmitis caused by E. faecalis in eyes with a PCR.

Risk factors for acute endophthalmitis following cataract surgery: a systematic review and meta-analysis

Background

Acute endophthalmitis is one of the most serious complications of cataract surgery and often results in severe visual impairment. Several risk factors for acute postoperative endophthalmitis (POE) following cataract surgery have been reported but the level of evidence and strength of association is varied. The purpose of this study was to critically appraise published reports on and to summarize clinical risk factors associated with acute POE which could be easily assessed by ophthalmologists for the introduction and implementation of preventive measure.

Methods

A systematic review and meta-analysis of observational studies was performed. Six databases were searched with no limits on the year or language of publication. Study-specific odds ratios (Ors) or relative risk (RR) of each risk factor were pooled using a random effect model.

Results

A total of 6 686 169 participants with 8 963 endophthalmitis in 42 studies were analyzed. Of the nine risk factors identified in our systematic review and meta-analysis, extra- or intracapsular cataract extraction, a clear corneal incision, without intracameral cefazolin (1 mg in 0.1 ml solution), without intracameral cefuroxime (1 mg in 0.1 ml solution), post capsular rupture, silicone intraocular lenses and intraoperative complications were found strongly associated with acute endophthalmitis. Other significant factors with a lower strength of association (risk estimates generally 1.5 or less) were male gender and old age (85 years and older).

Conclusions

Our study provides summary data on the risk factors for acute POE. Identifying patients at high risk of this sight-threatening eye disease is important from both the public health and clinical perspectives as this would facilitate detection of disease before the onset of irreversible visual loss enabling earlier intervention.

Adverse events and complications associated with intravitreal injection of anti-VEGF agents: a review of literature

Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is increasingly used for the treatment of a wide variety of retinal diseases, including age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions, and retinopathy of prematurity. Despite encouraging results in halting the disease and improving the vision, intravitreal injection of anti-VEGF agents may be associated with systemic adverse events and devastating ocular complications. In this review, we provide an overview of safety data for intravitreal injection of common anti-VEGF agents.

Role of topical, subconjunctival, intracameral, and irrigative antibiotics in cataract surgery

PURPOSE OF REVIEW

To summarize current understanding of antibiotic prophylaxis in cataract surgery, with particular emphasis on available evidence and change in practice patterns over the past decade.

RECENT FINDINGS

Povidone-iodine application prior to cataract surgery remains a universal practice, and is backed by good quality evidence. Subsequent to the results of the European multicenter trial documenting decreased risk of endophthalmitis with intracameral cefuroxime injection at the end of surgery, similar benefit with intracameral antibiotic use has been reported in studies with large sample sizes from multiple centers around the world. There has been a distinct change in practice patterns in many countries, with intracameral antibiotic use becoming part of routine protocol. In the USA, topical fluoroquinolone application remains the most popular mode of antibiotic prophylaxis. A promising approach is the development of novel drug delivery methods like polymeric devices designed for sustained antibiotic release.

SUMMARY

Based on current evidence, the recommended measures for endophthalmitis prophylaxis are preoperative topical instillation of povidone-iodine and intracameral antibiotic injection at the end of cataract surgery.

Moxifloxacin as postoperative prophylaxis for Enterococcus faecalis-induced endophthalmitis after cataract surgery in aphakic rabbits

PURPOSE

The development of endophthalmitis after cataract surgery often results in significant vision loss. Inhibition of bacterial proliferation in the anterior chamber using antibiotic eye drops is important to prevent endophthalmitis after cataract surgery. We aimed to determine the sensitivity of fluoroquinolones against Enterococcus faecalis ocular isolates and the efficacy of fluoroquinolones to prevent E. faecalis-induced endophthalmitis in aphakic rabbits.

METHODS

The minimum inhibitory concentrations (MICs) of moxifloxacin (MFLX) and levofloxacin (LVFX) used in ophthalmic solutions for 13 E. faecalis isolates obtained from the conjunctival sac or endophthalmitis cases were determined. Eye drops containing MFLX (0.5%), LVFX (0.5%), or saline were administered to aphakic rabbits with endophthalmitis induced by E. faecalis. The eye drops were administered immediately after lensectomy and at 3 and 6 h after cataract surgery (early instillation group) or immediately after lensectomy and at 12 and 15 h after cataract surgery (delayed instillation group). Bacterial growth, electroretinography (ERG), and slit-lamp examination (SLE) were determined throughout the course of infection.

RESULTS

In vitro susceptibility testing revealed that the MICs of MFLX for E. faecalis isolates were lower than those of LVFX. In the early ocular instillation groups, MFLX significantly improved SLE scores, ERG, and viable bacterial counts compared with LVFX and saline (all, P<0.05). There were no significant differences in any parameter between MFLX and saline in the delayed ocular instillation groups.

CONCLUSIONS

Early ocular instillation of MFLX delays retinal damage compared with LVFX when used to treat E. faecalis-induced endophthalmitis after cataract surgery.

Residual lens cortex material: potential risk factor for endophthalmitis after phacoemulsification cataract surgery

PURPOSE

To evaluate the bacterial growth potential of residual lens cortex after phacoemulsification with the development of endophthalmitis.

SETTING

University medical center.

DESIGN

Experimental study.

METHOD

Staphylococcus aureus and Staphylococcus epidermidis were dispensed into aqueous humor or serial dilutions of lens cortex that were obtained from cataract patients during phacoemulsification. After a 24-hour incubation, the colony-forming unit (CFU) was quantified. Eighty rabbits had phacoemulsification. Complete lens cortex removal was performed in 40 rabbits, while a quarter of lens cortex was retained in 40 rabbits. Staphylococcus aureus, with an inoculum size of 32 CFU, 56.3 CFU, and 108.6 CFU, was injected intracamerally at the conclusion of surgery and the production of endophthalmitis was measured 72 h later. The aqueous and vitreous humor samples were collected for microbiological diagnosis.

RESULTS

The increase in bacterial growth of S aureus and S epidermidis was statistically significantly greater in each dilution of lens cortex than in aqueous humor (P < .001, Student t test). With inoculum of 32.0 CFU or 56.3 CFU of S aureus, there was a statistically higher incidence of bacterial culture-proven endophthalmitis in the residual lens cortex eye group than in the normal aphakic eye group (P < .05, Fisher exact test).

CONCLUSIONS

Lens cortex was associated with a significant increase in bacterial growth compared with aqueous humor. Therefore, eyes with residual lens cortex seem more prone to develop endophthalmitis if anterior chamber bacterial contamination occurs during phacoemulsification.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.