Careful surgical technique and chemoprophylaxis are important for avoiding cystoid macular edema (CME) and endophthalmitis after lens-based surgery, said Bonnie An Henderson, MD.
“Meticulous surgery that minimizes the risk for intraoperative complications will help to prevent CME. Now there is also level 1 evidence showing the value of topical anti-inflammatory medications as a prophylactic strategy,” said Dr. Henderson, private practice, Ophthalmic Consultants of Boston, and clinical professor of ophthalmology, Tufts University School of Medicine, Boston.
Although for decades surgeons have been using topical nonsteroidal anti-inflammatory drugs (NSAIDs) peri- and postoperatively to prevent CME, strong data supporting this intervention continues to be reported with recent large studies.
Dr. Henderson noted that the American Academy of Ophthalmology Cataract in the Adult Eye Preferred Practice Pattern, which was released in 2016, stated that the available evidence suggests that NSAIDS only be used to prevent CME in patients with diabetic retinopathy or other high-risk ocular comorbidities. However, two recent meta-analyses, a report from the ASCRS Cataract Clinical Committee, and two recent prospective studies concluded that topical NSAIDs have value as a prophylactic strategy.
Particularly convincing is the ESCRS PREMED study that randomized 914 non-diabetic patients who underwent uneventful cataract surgery into one of three arms to receive topical bromfenac, topical dexamethasone, or bromfenac plus dexamethasone. The results showed the incidence of clinically significant macular edema was lowest in the group that received combination therapy and that postoperative macular thickness and total macular volume were lower in patients treated with the topical NSAID than in patients in the topical corticosteroid group.
A second arm of the ESCRS PREMED study focused on preventing CME in patients with diabetes. It included 213 patients. All participants were treated with topical bromfenac and topical dexamethasone, and they were randomized to receive no additional treatment, subconjunctival injection of triamcinolone, intravitreal bevacizumab 1.25 mg, or triamcinolone plus bevacizumab. Results of this study showed that macular thickness and macular volume were lowered by treatment with the subconjunctival corticosteroid, while the anti-VEGF injection had no significant benefit.
In 1991, a study by Speaker et al. demonstrated that microorganisms from the patient’s external tissues were the source of postoperative endophthalmitis, and preoperative preparation of the ocular surface with topical povidone-iodine is considered standard of care for reducing infection risk after surgery. Topical antibiotics pre- and postoperatively have also been used routinely despite absence of prospective studies demonstrating benefit for this approach.
“There are no studies that have shown superiority of topical antibiotic treatment versus povidone-iodine alone, and there is no consensus about what may be the best topical antibiotic for preventing endophthalmitis, although fluoroquinolones are used most often,” said Dr. Henderson.
There is very strong evidence supporting the efficacy of intracameral antibiotics for reducing the risk of postoperative endophthalmitis. Initial results from the landmark ESCRS study of prophylaxis of postoperative endophthalmitis were published in 2006 and showed that intracameral cefuroxime significantly reduced the risk for developing endophthalmitis after cataract surgery. Subsequently, findings of prospective studies conducted in Sweden and Kaiser Permanente in California among others support the use of intracameral antibiotics, Dr. Henderson said.
In addition, a recent meta-analysis by Bowen et al. found that both intracameral cefuroxime and intracameral moxifloxacin reduced the rates of endophthalmitis with minimal or no toxicity. The authors also concluded that intracameral antibiotic administration may be as effective used alone as when combined with a topical antibiotic. Authors of a Cochrane Database Systematic review concluded there is high-certainty evidence that intracameral cefuroxime with or without topical levofloxacin lowers the risk of endophthalmitis after surgery.
Dr. Henderson noted that antibiotics for endophthalmitis prophylaxis have also been given as a subconjunctival injection, but there is no evidence to show this method is superior to other techniques for antibiotic prophylaxis.
Studies have generated conflicting information on whether the risk of endophthalmitis after lens-based surgery is increased when the procedure is performed through a clear corneal incision versus a scleral tunnel incision. Careful construction of the incision, however, is important so that it remains watertight postoperatively and thereby prevents intraocular ingress of bacteria from the ocular surface.
Attention to intraoperative technique is also important for preventing endophthalmitis because prolonged surgery and certain intraoperative complications, including posterior capsule rupture and vitreous loss, are associated with an increased risk of postoperative infection.
Bonnie An Henderson, MD
This article was adapted from Dr. Henderson's presentation during Refractive Surgery Subspecialty Day at the 2018 meeting of the American Academy of Ophthalmology. Dr. Henderson is a consultant to Alcon Laboratories, Allergan, Sun Pharmaceuticals, and Kala Pharmaceuticals and receives lecture fees from Alcon.