Eyeworld

JULY 2021 | EYEWORLD | 133 G Contact Okeke: cokeke@cvphealth.com Vinod: kvinod@nyee.edu References 1. Vaziri K, et al. Incidence of bleb-associated endophthal- mitis in the United States. Clin Ophthalmol. 2015;9:317–322. 2. Mitchell W, et al. The effective- ness of intracameral moxifloxa- cin endophthalmitis prophylaxis for trabeculectomy. Ophthalmol Glaucoma. 2021;4:11–19. 3. Islam YFK, et al. Management of endophthalmitis related to glaucoma drainage devices: review of the literature and our experience. Eye (Lond). 2021. Online ahead of print. Relevant disclosures Okeke: Allergan, Glaukos, Ivantis, MST, Nova Eye Medical, Santen, Sight Sciences Vinod: None "When intraocular infections do occur, they must be recognized and treated immediately and aggressively to optimize visual outcomes," Dr. Vinod said. In cases of blebitis, she advised taking a culture from the bleb when possible to better identify the causative organism and beginning treatment with topical broad spectrum (usually fortified) antibiotics right away. "Although consensus guidelines are lack- ing, we have a low threshold for performing early vitrectomy with intraoperative intravitreal injection of antibiotics in cases of bleb-related endophthalmitis since the causative organisms tend to be more virulent than those associat- ed with endophthalmitis following cataract surgery," Dr. Vinod said. "Similarly, no consen- sus exists regarding the management of tube shunt-related endophthalmitis, including the role of vitrectomy. Some surgeons prefer to remove the tube shunt in eyes with endoph- thalmitis due to concerns for the growth of a bacterial biofilm within the implant." A study based on a literature review pub- lished in the journal Eye compared outcomes of explantation of glaucoma drainage devices (GDD) with device retention and compared the outcomes of pars plana vitrectomy vs. antibiot- ics alone in patients who had endophthalmitis. Ultimately, the authors found that explantation of the devices and immediate vitrectomy were "both associated with better anatomical out- comes in GDD-related endophthalmitis." 3 Dr. Okeke said how blebs are created has also changed over the last 10 years and could be improving infection stats as well. "We tend to make them more diffuse, and as a result the blebs tend to be less elevated and less ischemic; this can help reduce the risk of bleb leaks in the future," she said. than infections post-cataract surgery. One study based on 5-year, retrospective data saw a 0.55% risk of blebitis and 0.45–1.3% risk of endoph- thalmitis after glaucoma filtering surgery. 1 The risk of infection in a bleb-forming procedure is lifelong and thus patients require extensive counseling preop for the symptoms to look out for, Dr. Vinod said. Dr. Vinod said most surgeons prescribe topical, broad spectrum antibiotics for 1 week postop, and there has been increased interest in intracameral antibiotics during glaucoma filtering procedures. Just this year, a study of cases from Aravind Eye Hospital showed a four- fold lower rate of endophthalmitis in patients who received intracameral moxifloxacin during trabeculectomy or trab combined with phaco. 2 With tube shunts, she said they are being positioned to maximize eyelid coverage (around the 12 o'clock position for superotemporal implants and 6 o'clock for inferonasal implants) and minimize macrotrauma from eyelid rubbing that could lead to conjunctival erosion. "Also, we have graft materials that are maybe better to cover the tube," Dr. Okeke said. "You can also sometimes have erosion of the conjunctiva, but if you have corneal graft mate- rial and you put the epithelium on the outside, that can sustain exposure to the atmosphere and not necessarily erode. … The epithelium can maintain stability." Dr. Vinod noted the importance of a water- tight conjunctival closure for these procedures to avoid early-onset wound leak that could serve as a conduit for pathogens. "In the same vein, I always suture my clear corneal main wound when performing cataract surgery in combination with incisional glauco- ma surgery, even if the wound already appears to be watertight, as lower postoperative IOPs can increase the risk of wound leak," she said. Both Drs. Vinod and Okeke emphasized the importance of inspecting the bleb or tube at each visit with the patient for leak or erosion, respectively. Both are opportunities for infection to occur and should be addressed promptly with surgical revision.

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