Year : 2018 | Volume
: 56 | Issue : 3 | Page : 194--196
Postoperative endophthalmitis: Preventive measures
R. K. Eye Care Centre, Namakkal, Tamil Nadu, India
R. K. Eye Care Centre, 18/A, GVR Mill Street, Rasipuram, Namakkal, Tamil Nadu
Although rare, postoperative endophthalmitis is one of the most feared complications of cataract surgery. It may significantly compromise visual function and even the anatomical integrity of the eye. Despite the significant reduction in recent years, considering the millions of people who undergo cataract surgery each year, postoperative endophthalmitis still poses a significant public health issue, and every step should be taken to reduce its occurrence. In addition to the use of Povidone iodine 5% solution in the conjunctival sac few minutes prior to surgery, proper construction of wound and use of prophylactic intracameral antibiotics play a mojor role in reducing the incidence of postoperative endophthalmitis.
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Vasumathi R. Postoperative endophthalmitis: Preventive measures.TNOA J Ophthalmic Sci Res 2018;56:194-196
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Vasumathi R. Postoperative endophthalmitis: Preventive measures. TNOA J Ophthalmic Sci Res [serial online] 2018 [cited 2020 Aug 15 ];56:194-196
Available from: http://www.tnoajosr.com/text.asp?2018/56/3/194/243770
Endophthalmitis following cataract surgery is rare but continues to be a serious complication which every ophthalmic surgeon and patient strives to avoid. The visual loss and debilitation that occur in a large proportion of postoperative endophthalmitis cases can be severe and irreversible. Morbidity associated with postoperative endophthalmitis is related not only to acute process but also to late sequelae. Those most in need of the operation are often those at greatest risk, such as the elderly. Prevention and elimination of postoperative endophthalmitis, however, is a constant goal of every ophthalmic surgeon. Preoperative identification of risk factors and effective prophylaxis could help in reducing its incidence.
Postoperative endophthalmitis is an inflammatory condition of the eye due to an infectious process from bacteria, fungi, or, on rare occasions, parasites. Typically, postoperative endophthalmitis is caused by the perioperative introduction of microbial organisms into the eye either from the patient's normal conjunctival and skin flora or from contaminated instruments. Once organisms gain access to the vitreous cavity, overwhelming inflammation is likely to occur, making rapid recognition, diagnosis, and treatment critical in optimizing final outcomes. Although most cases of postoperative endophthalmitis occur within 6 weeks of surgery, infections seen in high-risk patients or infections caused by slow-growing organisms may occur months or years after the procedure.
It has been demonstrated that most isolates causing clinical endophthalmitis are introduced into the eye from the patient's conjunctival flora. However, contamination of sterilized instruments, disposable supplies, prepared solutions, surgical field, or the intraocular lens, all have also been reported. Clusters of endophthalmitis have resulted from these types of external contaminations.
Once bacteria are introduced into the eye, risk factors that may increase the risk of endophthalmitis include rupture of the posterior capsule, retained lens material, and prolonged surgical time. Published studies have demonstrated an increased risk of endophthalmitis after the placement of a secondary intraocular lens, possibly due to increased surgical time or ocular manipulation.
Once clinical infection occurs, damage to ocular tissues is believed to occur due to direct effects of bacterial replication as well as the initiation of a fulminant cascade of inflammatory mediators. Endotoxins and other bacterial products appear to cause direct cellular injury while eliciting cytokines that attract neutrophils, which enhance the inflammatory effect.
In general, the risk of severe visual loss in patients with acute endophthalmitis is higher in patients who develop infections from more virulent organisms and do not seek treatment promptly. Fortunately, 70%–80% of patients with postoperative endophthalmitis have infections caused by coagulase-negative staphylococci, and the visual prognosis in these cases is usually good with rapid treatment.
In the Endophthalmitis Vitrectomy Study (EVS), a prospective randomized clinical trial that evaluated the management of acute postoperative endophthalmitis, the most common organisms isolated were coagulase-negative staphylococci (70%), Staphylococcus aureus (9.9%), and streptococci species (9.0%). Infections caused by Gram-negative organisms were seen in 6% of cases.
Endophthalmitis following other types of intraocular surgery has a similar microbiological profile with the following exceptions:
In filtering bleb-associated cases, the most common offending species is Streptococcus, followed by Haemophilus influenzae and coagulase-negative staphylococci In chronic postoperative endophthalmitis, an important causative organism is Propionibacterium acnes, a slow-growing, Gram-positive bacillus that is associated with a characteristic white, intracapsular plaque that develops weeks to months and years after cataract surgery Coagulase-negative staphylococci, fungal species, and unusual Gram-negative organisms have also been reported to cause chronic postoperative endophthalmitis.
Given the poor visual outcome of many cases of postoperative endophthalmitis, an important focus should be on the prevention of this dreaded surgical complication.
Operation theater environment
There is a general relationship between aerobic bacterial count and risk of infection. The risk of infection is significant with counts in the range of 700–1800 bacteria-carrying particles (BCPs) per cubic meter, but the risk becomes insignificant when the BCP load is <180 per cubic meter. Unattended air-conditioning filter systems are often the culprits, and regular maintenance of the filters is of paramount importance. Unwanted instruments and old unused machines should not be kept in the operation room. Surgical procedure rooms and scrub/utility areas should be terminally cleaned daily. This is done to reduce the number of microorganisms, dust, and organic debris present in the environment.
Health of patients
Patients with local-risk factors such as those with chronic blepharitis, conjunctivitis, discharge or dacryocystitis and those with systemic risk factors such as diabetes or immunodeficiency disorders and those taking immunosuppressant medications are more likely to harbor methicillin-resistant organisms. It is, therefore, prudent to ensure that patients undergoing an ocular surgery are free from local or systemic infections.
Povidone–iodine is an antiseptic used for skin disinfection of patients and hands of the healthcare providers. It has minimal toxicity but produces powerful antimicrobial effect after 1 min of skin contact. This effect is attributed to the release of free iodine and persists for at least 1 h. It is believed that iodine penetrates the cell wall and reacts with amino acids and nucleotides, which ultimately disrupts the cell's protein synthesis. Povidoneiodine is recommended for both skin (10% solution) and conjunctival (5% solution) application. Ideally, it should dry after skin preparation and conjunctival cul-de-sac should not be irrigated before 1 min contact time.
Care of eyelashes and lacrimal system
Preparation of the eye at the time of surgery is critical. Adherence to strict aseptic protocol with use of an eyelid speculum and isolation of the eyelid margin and eyelashes from the surgical field with adhesive draping is a proven method of minimizing contamination of the surgical field and reducing the risk of infection.
Postcataract surgery endophthalmitis is more likely with corneal incisions. Incision design and construction play pivotal roles in increased rates of infection with corneal tunnels. Poorly constructed and distorted wounds could contribute to a greater chance of postoperative anterior chamber contamination. Hypotony in the setting of a sutureless wound may potentially lead to a poorly sealing wound with higher risk of ocular surface bacteria gaining access into the eye. If, at the completion of any ophthalmic procedure, there appears to be incompetence of the wound or the eye fails to hold a normal pressure, the incision should be sutured to achieve a water-tight seal.
Moxifloxacin is a fourth-generation fluoroquinolone with a broad spectrum of coverage that includes both Gram-positive and Gram-negative bacteria and many anaerobes. The high aqueous concentration achieved by an intracameral injection should be highly effective against sensitive organisms because moxifloxacin's bactericidal efficacy is concentration dependent. Studies conducted in high-volume centers have shown that routine use of intracameral moxifloxacin achieved a highly significant, 4-fold reduction in postoperative endophthalmitis in patients undergoing cataract surgery. Moxifloxacin is an effective intracameral prophylactic antibiotic and should be considered for cataract surgery.
Postoperative endophthalmitis is a devastating complication following cataract surgery, and every step should be taken to reduce its occurrence.
Since most isolates causing clinical endophthalmitis are introduced into the eye from the patient's conjunctival flora, measures should be taken to reduce the microbial load of the conjunctival sac using instillation of povidone–iodine into the conjunctival sac before surgeryWound construction should be done meticulously and suturing is to be done at the end of the surgery if wound leak and hypotony are anticipatedPooling of irrigating fluid in the conjunctival sac and contact of intraocular lens to conjunctival surface need to be avoidedIntracameral moxifloxacin is an effective prophylactic measure and should be considered for cataract surgeryApart from strict aseptic protocol, periodic maintenance of sterilizers and checking the integrity of packing of disposable supplies are to be followed. Irrigating fluids should be inspected for any suspended particlesRegular maintenance of the air-conditioner filters is of paramount importance. Unwanted instruments and old unused machines should not be kept in the operation room. Surgical procedure rooms and scrub/utility areas should be terminally cleaned dailyA thorough preoperative clinical assessment of the patient should be done, and the clinical illnesses should be well controlled or treated before proceeding with surgery.
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Conflicts of interest
There are no conflicts of interest.
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