Electroretinographic evaluations of bleb-related endophthalmitis after vitrectomy with 0.025% povidone iodine irrigation

Electroretinographic evaluations of bleb-related endophthalmitis after vitrectomy with 0.025% povidone iodine irrigation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Electroretinographic evaluations of bleb-related endophthalmitis after vitrectomy with 0.025% povidone iodine irrigation Koki Sakata, Takeshi Katsumoto, Tomoyuki Kumagai, Kei Shinoda This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3932930/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Vitrectomy with 0.025% povidone-iodine (0.025% PI) in the irrigation solution was recently reported to be used to treat filtering bleb-associated endophthalmitis. However, iodine is known to be retinotoxic but it depends on its concentration. Electroretinography (ERGs) can be used to evaluate the retinal function, but the contact lens electrodes used to pick up the ERGs can affect the filtering bleb adversely. We performed ERGs with skin electrodes on eyes with bleb-associated endophthalmitis that had undergone vitrectomy with 0.025% PI irrigation. Case presentation: Case 1 was a 46-year-old man who underwent trabeculectomy for steroid induced glaucoma. One month postoperatively, a filtering bleb-associated endophthalmitis was suspected, and vitreal and subconjunctival injections of vancomycin (VCM) and ceftazidime (CAZ), and frequent antibiotic eye drops were started. After three days, an exacerbation of the endophthalmitis was observed and vitrectomy with 0.025% PI irrigation was performed. One month after the surgery, the visual acuity improved from hand movements to counting fingers. Pre- and postoperative ERGs recorded using skin electrodes showed an improvement in the a- and b-wave amplitudes and the b/a ratio was stable at approximately 2.0. Case 2 was a 63-year-old man who had undergone phacovitrectomy for proliferative diabetic retinopathy eleven years earlier and trabeculectomy for glaucoma five years earlier in the left eye. Five years after the surgery, the eye developed blebitis, and frequent antibiotic eye drops and subconjunctival injections of VCM and CAZ were performed. Three days later, vitreous opacities appeared and a high brightness area was observed in the B-mode echo images. A diagnosis of bleb-associated endophthalmitis was made, and vitrectomy with 0.025% PI irrigation was performed. The preoperative visual acuity was hand movements, and it improved to 0.01 one month after the surgery. Comparisons of the postoperative to the preoperative ERGs found that the a- and b- wave amplitudes increased and the b/a ratio was stable at approximately 1.5 postoperatively. Conclusions ERG recordings with skin electrodes are helpful for evaluating postoperative retinal function in cases of bleb-associated endophthalmitis. Vitrectomy with 0.025% PI irrigation is effective and most likely safe for the treatment of bleb-associated endophthalmitis. blebitis electroretinography bleb-related endophthalmitis povidone iodine irrigation vitrectomy Figures Figure 1 Figure 2 Background Bleb-related infections are a severe complication that can develop after mitomycin C-augmented trabeculectomy or trabeculectomy alone. 1 , 2 They develop at a mean frequency of 6.9 ± 5.8 years after the surgery, and the 5-year cumulative incidence is 2.2 ± 0.5%. This incidence is higher than that of infections after cataract surgery. 1 The infections are classified into three stages. 3 – 5 Stage I or blebitis is an infection confined to the bleb site with a mild cellular reaction in the anterior chamber. A Stage II infection affects mainly the anterior chamber and the vitreous is not involved. A Stage III infection involves the posterior part of the eye, and it is subdivided into Stage IIIa with mild involvement of the vitreous and Stage IIIb with more advanced involvement of the vitreous. The inflammation of the bleb (Stage III) can spread to the vitreous in 31.5% (46/146) of the eyes which causes a significant reduction of vision and an ekevatuib of the intraocular pressure (IOP) within 12 months. 6 Repeated intravitreal injections of antibiotics for Stage IIIa, and immediate vitreous surgery for Stage IIIb are recommended. In addition to the surgical removal of the infected vitreous, topical and intravitreal vancomycin (VCM) and ceftazidime (CAZ) are used as first-line treatments that have broad-spectrum antibacterial activity with a low potential for developing resistance. 7 Recently, Nakashizuka and his colleagues reported that vitrectomy using an irrigation solution containing 0.025% povidone-iodine (PI) followed by postoperative antibiotics was safe and effective for the treatment of endogenous endophthalmitis and postoperative endophthalmitis including blebitis-related endophthalmitis. 8 – 10 However, there are several reports on the toxicity of PI on the retina, 11 – 14 and only limited information is available on its safety in human eyes with severe endophthalmitis. 9 , 10 Electroretinography (ERG) can be used to evaluate the physiology of the retina of the eye objectively 9 , however the contact lens electrodes used to pick-up the ERGs can affect the filtering bleb. To overcome this problem, skin electrodes can be used to record the ERGs without affecting the filtering bleb and avoid the risk of infection. 15 We present the results of pars plana vitrectomy (PPV) with irrigation of 0.025% PI in balanced salt solution (BSS) PLUS (Alcon Laboratories, Fort Worth, TX) in two cases of bleb-related endophthalmitis. The retinal function was evaluated by full-field ERGs recorded before and after the vitrectomy with irrigation containing PI. The procedures used on these patients were approved by the Ethics Committee of Saitama Medical University (No.2021-073), and the study was conducted in accordance with the tenets of the Declaration of Helsinki. A signed written informed consent was obtained from the two patients who participated in this study. Case Presentation Case 1 was a 46-year-old man who complained of ocular pain in his left eye in July of 202X. His best-corrected visual acuity (BCVA) in the left eye was 0.2 and the intraocular pressure (IOP) was 23.9 mmHg. He had been diagnosed with atopic keratoconjunctivitis which was treated with antibiotic and steroid eye drops, and steroid-induced glaucoma developed in his left eye. Trabeculectomy had been performed one month before our examination. Our slit-lamp examination showed conjunctival hyperemia, mild opacity of the superior cornea, and cells and mild flare in the anterior chamber ( Fig. 1 ) . The anterior vitreous opacification was mild, but the visibility of the fundus was poor. Clear optical coherence tomographic (OCT) images were not available. A mild, filter bleb-associated endophthalmitis was suspected which was treated by intravitreal and subconjunctival injections of VCM, ceftazidime (CAZ), and frequent antibiotic eye drops. Examinations of the cultures of the secretions around the bleb were negative. Three days later, his BCVA decreased to hand movements at 0.5 meters, the fundus was not visible, and B-mode echography showed a high brightness area. He was diagnosed with an exacerbation of the endophthalmitis (Stage IIIb), He was treated with vitrectomy with VCM, CAZ, and 0.025% PI irrigation. One month after the surgery, the visual acuity improved to counting fingers at 0.5 meters. Full-field ERGs were recorded pre- and postoperatively with the RETeval system (LKC Technologies, Gaithersburg, MD; Welch Allyn, Skaneateles Falls, New York, USA), a portable ERG device that uses skin electrodes and whose recording conditions conformed to the standards of the International Society for Clinical Electrophysiology of Vision (ISCEV). 16 Comparisons of the pre- and postoperative ERGs showed an improvement of the a- and b-wave amplitudes and a stable b/a ratio of approximately 2.0 ( Fig. 1 ) . The implicit times of both waves did not change significantly. Case 2 was a 63-year-old man who complained of ocular pain in his left eye on March, 202X. His BCVA in the left eye was hand movements at 0.5 meters, and the IOP was 15.0 mmHg. He had undergone phacovitrectomy for proliferative diabetic retinopathy (PDR) 11 years earlier and had undergone trabeculectomy for glaucoma of the left eye 5 years earlier. Slit-lamp examination showed conjunctival hyperemia, and cells and moderate flare in the anterior chamber ( Fig. 2 ) . Ophthalmoscopy showed mild vitreous opacity, and the OCT image was not clear but the retina could be seen to be atrophic probably due to the PDR. A bleb-associated endophthalmitis (Stage IIIa) was suspected. Intravitreal injections of VCM and CAZ, frequent antibiotic eye drops, and subconjunctival injections of VCM and CAZ were performed. Klebsiella pneumoniae was detected in the cultures of the secretions around the bleb. Three days later, the vitreous opacity worsened, and a high brightness area was observed in the B-mode echography images. A diagnosis of bleb-associated endophthalmitis (Stage IIIb) was made, and PPV with VCM, CAZ, and 0.025% PI irrigation was performed. The visual acuity recovered to 0.01 one month after the beginning of the treatments. Full-field ERGs were recorded pre- and postoperatively with the RETeval system with the skin electrode. A comparison of the pre- and postoperative ERGs showed that the a- and b- wave amplitudes increased but the b/a ratio was not significantly changed at approximately 1.5 months postoperatively. The implicit times of both waves was also not significantly changed ( Fig. 2 ) . Discussion and Conclusions The microorganisms responsible for bleb-associated endophthalmitis can be identified in cultures but about 50% of cases are culture-negative. The most frequently detected organisms are members of the Staphylococcus and Streptococcus genus. 2 , 6 PI acts directly on the membrane proteins of bacteria and viruses to inactivate them, and thus acts with or without drug resistance. The time for antimicrobial action is as short as 15 seconds at a 0.025% concentration. 8 K. influenzae and enterococci have also been detected in grade IIIb filtering bleb-related infections. 6 There is also a report that VCM-resistant enterococci were detected as the causative pathogen of filtering bleb-related endophthalmitis. 17 Our results showed that 0.025% PI irrigation in combination with antimicrobial perfusion can be effective in treating cases where the causative organism is not known or in cases where the organisms are drug-resistant. Because PI acts directly on the membrane proteins of bacteria and viruses to inactivate them, there is a low probability for microorganisms to become resistant to it. Another advantage of PI is the rapidity of its action. Iodine is known to be retinotoxic depending on its concentration which raises the possibility of retinal toxicity with its use. 11 – 14 In experiments on rabbits, PI at concentrations of 0.027% or lower showed no histological abnormalities to the intraocular tissues. 12 Intravitreal administration of 0.1 mL of 1.25% PI and irrigation of the vitreous cavity with 0.025% PI for 15 minutes for endophthalmitis showed no decrease of retinal function on postoperative ERGs. 9 In addition, there is only one report of two cases that used 0.025% PI combined with antibiotics in the irrigation solution during vitrectomy for filtering bleb-associated endophthalmitis. 10 Unfortunately, the authors did not perform ERG recordings. In our two cases, there was no postoperative reduction of retinal function as shown by the ERGs as reported earlier. The presence of endophthalmitis has been determined by the visual acuity in most previous studies. 2 , 7 , 9 , 10 , 18 – 20 Although perimetry and ERGs are helpful in assessing the function of the entire retina, there are only a small number of studies using these methods probably because of their inconvenience for the patients. 9 , 21 The RETeval system is a relatively new ERG recording system that uses skin electrodes and is less invasive. 22 We showed that the ERGs recorded with a skin electrode can be used to evaluate the retinal function in the early postoperative period even in eyes after filtration surgery in which contact lenses and DTL electrodes cannot be used. 15 , 23 , 24 These were only two cases, and the safety and effectiveness of this treatment cannot be applied to all cases because there are many factors that influence the presence of endophthalmitis. It is necessary to investigate a larger number of cases to determine whether a recurrence of endophthalmitis can be resolved and prevented by this method. Nevertheless, we believe that these findings will contribute to the establishment of a treatment protocol for bleb-associated endophthalmitis. In conclusion, vitrectomy with 0.025% PI irrigation is an effective and probably safe method to treat bleb-associated endophthalmitis. ERG recordings with skin electrodes can be used to evaluate the perioperative retinal function of bleb-associated endophthalmitis. Declarations Ethical Approval and Consent to participate The study was conducted according to the guidelines of the Declaration of Helsinki. The study protocol was approved by the Ethical Committee of Saitama Medical University (2021-073). Written informed consent was obtained from participants after full explanation of the diagnosis and treatment. Consent for publication Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Copies of the written consent are available for review by the Editor-in-Chief of this journal. Availability of supporting data All data generated or analyzed during the current study are included in this published article. Competing interests The authors have no conflicts of interest to declare. Funding Sources This study was supported in part by a grant to KS from the Japan Society for the Promotion of Science (JSPS; KAKENHI grant number: 22K09838). Authors’ Contributions KoS, TaK, and KeS contributed to the study Concepts and Study Design; KoS, ToK, and TaK cared and examined patients; KoS and TaK were responsible for data acquisition; KoS, TaK, and KeS were responsible for data analysis; KoS and KeS were responsible for manuscript preparation and editing; KoS and TaK critically reviewed the manuscript. All authors agree to be accountable for all aspects of work. Patient anonymity is preserved. All authors attest that they meet the current ICMJE criteria for authorship. Acknowledgements The authors thank Professor Emeritus Duco Hamasaki of the Bascom Palmer Eye Institute for discussions and editing this manuscript. References Yamamoto T, Sawada A, Mayama C, Araie M, Ohkubo S, Sugiyama K, et al. The 5-year incidence of bleb-related infection and its risk factors after filtering surgeries with adjunctive mitomycin C: collaborative bleb-related infection incidence and treatment study 2. Ophthalmology. 2014;121:1001–6. Song A, Scott IU, Flynn HW, Flynn HW Jr, Budenz DL. Delayed-onset bleb-associated endophthalmitis: clinical features and visual acuity outcomes. Ophthalmology. 2002;109:985–91. Azuara-Blanco A, Katz LJ. Dysfunctional filtering blebs. Surv Ophthalmol. 1998;43:93–126. Greenfield DS. Bleb-related ocular infection. J Glaucoma. 1998;7:132–6. Yamamoto T, Kuwayama Y. Collaborative Bleb-related Infection Incidence and Treatment Study Group. Interim clinical outcomes in the collaborative bleb-related infection incidence and treatment study. 2011;118:453–8. Yamamoto T, Kuwayama Y, Kano K, Sawada A, Shoji N. Study Group for the Japan Glaucoma Society Survey of Bleb-related Infection. Clinical features of bleb-related infection: a 5-year survey in Japan. Acta Ophthalmol. 2013;91:619–24. Pijl BJ, Theelen T, Tilanus MA, Rentenaar R, Crama N. Acute endophthalmitis after cataract surgery: 250 consecutive cases treated at a tertiary referral center in the Netherlands. Am J Ophthalmol. 2010;149:482-7.e1-2. Nakashizuka H, Shimada H, Hattori T, Noguchi T, Kokubo N, Yuzawa M. Vitrectomy using 0.025% povidone-iodine in balanced salt solution plus for the treatment of postoperative endophthalmitis. Retina. 2015;35:1087–94. Nakashizuka H, Shimada H, Hattori T, Tanaka K, Kitagawa Y, Shinoda K. Intravitreal injection of 1.25% povidone iodine followed by vitrectomy using 0.025% povidone iodine irrigation for treating endophthalmitis. Transl Vis Sci Technol. 2019;8:21. 10.1167/tvst.8.1.21 . Kitagawa Y, Shimada H, Nakashizuka H, Hattori T, Yamazaki Y. Intraocular lens implantation and vitrectomy using 0.025% povidone-iodine in irrigation solution for bleb-related endophthalmitis. Int J Ophthalmol. 2020;13:1499–502. Whitacre MM, Crockett RS. Tolerance of intravitreal povidone-iodine in rabbit eyes. Curr Eye Res. 1990;9:725–32. Trost LW, Kivilcim M, Peyman GA, Aydin E, Kazi AA. The effect of intravitreally injected povidone-iodine on Staphylococcus epidermidis in rabbit eyes. J Ocul Pharmacol Ther. 2007;23:70–7. Kim KH, Cao J, Yoo JW, Yoon IS, Jung JW, Lee JE, et al. Intraocular pharmacokinetics of povidone-iodine and its effects on experimental Staphylococcus epidermidis endophthalmitis. Invest Ophthalmol Vis Sci. 2015;56:6694–700. Shimada H, Kato K, Ishida K, Yamaguchi T, Shinoda K. Evaluation of Retinal Function and Pathology After Intravitreal Injection of Povidone-Iodine and Polyvinyl Alcohol-Iodine in Rabbits. Transl Vis Sci Technol. 2020;9:5. 10.1167/tvst.9.5.5 . Igawa Y, Shoji T, Weinreb R, Miyake Y, Yoshikawa Y, Takano S, et al. Br J Ophthalmol. 2022;107:1295–302. Robson AG, Frishman LJ, Grigg J, Hamilton R, Jeffrey BG, Kondo M, et al. ISCEV Standard for full-field clinical electroretinography (2022 update). Doc Ophthalmol. 2022;144:165–77. Tang CW, Cheng CK, Lee TS. Community-acquired bleb-related endophthalmitis caused by vancomycin-resistant enterococci. Can J Ophthalmol. 2007;42:477–8. Islam YFK, Blake CR, Gibran SK. Management of endophthalmitis related to glaucoma drainage devices: review of the literature and our experience. Eye (Lond). 2021;35:1850–8. Choi JA, Chung SK. Postoperative Endophthalmitis following Cataract Surgery in Asia. ISRN Ophthalmol. 2011;917265. 10.5402/2011/917265 . Joseph J, Nirmalkar K, Mathai A, Sharma S. Clinical features, microbiological profile and treatment outcome of patients with Corynebacterium endophthalmitis: review of a decade from a tertiary eye care centre in southern India. Br J Ophthalmol. 2016;100:189–94. Hu J, Ma H, Li T, Zhu X, Tang S. Retina translocation for a patient with endogenous fungal endophthalmitis: long-term follow-up. Graefes Arch Clin Exp Ophthalmol. 2012;250:1237–40. Yasuda S, Kachi S, Ueno S, Piao CH, Terasaki H. Flicker electroretinograms before and after intravitreal ranibizumab injection in eyes with central retinal vein occlusion. Acta Ophthalmol. 2015;93:e465–8. Shibuya M, Yoshikawa Y, Katsumoto T, Shoji T, Kondo H, Miyakoshi H et al. Electroretinographic recordings with skin electrodes to assess effects of vitrectomy with gas tamponade on eyes with rhegmatogenous retinal detachment. Sci Rep 2019;9:19948. 10.1038/s41598-019-56307-z . Terauchi G, Shinoda K, Sakai H, Kawashima M, Matsumoto CS, Mizota A, et al. Retinal function determined by flicker ERGs before and soon after intravitreal injection of anti-VEGF agents. BMC Ophthalmol. 2019;19:129. 10.1186/s12886-019-1129-7 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3932930","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":272026068,"identity":"1ff6bbe5-b6c9-47b8-8155-6842b07f9c41","order_by":0,"name":"Koki Sakata","email":"","orcid":"","institution":"Saitama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Koki","middleName":"","lastName":"Sakata","suffix":""},{"id":272026069,"identity":"95aa09ab-ba5a-419a-a7d0-7dfb6e8ca0e8","order_by":1,"name":"Takeshi Katsumoto","email":"","orcid":"","institution":"Saitama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Takeshi","middleName":"","lastName":"Katsumoto","suffix":""},{"id":272026070,"identity":"3df60bc7-8399-4a19-be84-5b8fcf2c9c1d","order_by":2,"name":"Tomoyuki Kumagai","email":"","orcid":"","institution":"Saitama Medical University","correspondingAuthor":false,"prefix":"","firstName":"Tomoyuki","middleName":"","lastName":"Kumagai","suffix":""},{"id":272026071,"identity":"236c5d41-4623-4db5-90c4-41d3515c8d9d","order_by":3,"name":"Kei Shinoda","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABC0lEQVRIiWNgGAWjYDACCcYGBoYDNgwMzHChBBDBRkhLGlALXA9BLSDiwGEGJGsS8LtLfnZz24MPZ87b87fzH/x0o4Yhmp89gfHDDwa+PFxaDO4cbDecceN24ozDzMzSOccYcmf2PGCW7GFgK8apRSKxTZrnw+0EhsPMDNI5bP9zN9xIYJAG+iWxAZfDZoC1nLOXB9ryO+cfQ+7+GwnMv/FpYbgB0nLjAOOGw8xs0rltDLkbJBLY8NpiANQiOeNMcuLGw8xm1rl9DLkzzjxss+wxwO0X+RnpzyQ+HLOzlzt/8PHtnG8Muf3tyYdv/Kg4hjPEsAFQ5BocSyBFCxjUkK5lFIyCUTAKhisAADmzWL/LfkXFAAAAAElFTkSuQmCC","orcid":"","institution":"Saitama Medical University","correspondingAuthor":true,"prefix":"","firstName":"Kei","middleName":"","lastName":"Shinoda","suffix":""}],"badges":[],"createdAt":"2024-02-06 05:48:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3932930/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3932930/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":51077748,"identity":"b16ad20b-fce2-43cf-a733-b84dee74fc16","added_by":"auto","created_at":"2024-02-13 18:51:14","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1187687,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSlit-lamp images, fundus photographs, optical coherence tomographic (OCT) images, and electroretinograms (ERGs) before and during the course of the bleb-associated endophthalmitis in Case 1.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUpper left.\u003cstrong\u003e \u003c/strong\u003eSlit-lamp image on the initial visit showing an avascular bleb, conjunctival hyperemia, and mild upper corneal opacity.\u003c/p\u003e\n\u003cp\u003eUpper right.\u003cstrong\u003e \u003c/strong\u003eFundus photograph 4 days after surgery showing an intact retinal circulation and pale optic disc.\u003c/p\u003e\n\u003cp\u003eMiddle.\u003cstrong\u003e \u003c/strong\u003eOptical coherence tomographic (OCT) image 3 days after the surgery showing a thinning of the inner retinal layer.\u003c/p\u003e\n\u003cp\u003eLower left.\u003cstrong\u003e \u003c/strong\u003eMixed rod-cone electroretinogram (ERG) on the initial visit. The a- and b- wave amplitudes are moderately attenuated.\u003c/p\u003e\n\u003cp\u003eLower right.\u003cstrong\u003e \u003c/strong\u003eMixed rod-cone ERG 3 days after the surgery. The a- and b-wave amplitudes are larger than the preoperative values, and the b/a ratio is not changed at approximately 2.0 postoperatively. The implicit time of both waves is not altered. Note that the vertical axis representing the amplitude has a different scale.\u003c/p\u003e","description":"","filename":"case120230921300dpi.png","url":"https://assets-eu.researchsquare.com/files/rs-3932930/v1/56c921860f1138cb7488c39b.png"},{"id":51077747,"identity":"e5ba25e7-11a8-49cd-9cfa-4e957d645371","added_by":"auto","created_at":"2024-02-13 18:51:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1041118,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSlit-lamp images, fundus photographs, optical coherence tomographic (OCT) images, and electroretinograms (ERGs) before and during the course of the bleb-associated endophthalmitis in Case 2.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUpper left.\u003cstrong\u003e \u003c/strong\u003eSlit-lamp image on the initial visit showing an avascular bleb, conjunctival hyperemia, and mild upper corneal opacity.\u003c/p\u003e\n\u003cp\u003eUpper right.\u003cstrong\u003e \u003c/strong\u003eFundus photograph 6 days after surgery showing intact retinal circulation and pale optic disc.\u003c/p\u003e\n\u003cp\u003eMiddle.\u003cstrong\u003e \u003c/strong\u003eOptical coherence tomographic (OCT) image 6 days after surgery showing a thinning of the inner retinal layer.\u003c/p\u003e\n\u003cp\u003eLower left.\u003cstrong\u003e \u003c/strong\u003eMixed rod-cone ERG on the initial visit. The a- and b- wave amplitudes are markedly reduced.\u003c/p\u003e\n\u003cp\u003eLower right.\u003cstrong\u003e \u003c/strong\u003eMixed rod-cone ERG 6 days after surgery. Compared to the pre-operative response, the a- and b-wave amplitudes are larger, and the b/a ratio has not changed at approximately 1.5. The implicit time of both waves is almost unchanged.\u003c/p\u003e","description":"","filename":"case220230921300dpi.png","url":"https://assets-eu.researchsquare.com/files/rs-3932930/v1/c7de29819dc82a754cb54d58.png"},{"id":51080058,"identity":"6ba3e4ea-f07d-451c-9c69-32018501968e","added_by":"auto","created_at":"2024-02-13 19:07:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3272985,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3932930/v1/b2f49830-f921-4bb3-a286-a57ba9bfecdc.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Electroretinographic evaluations of bleb-related endophthalmitis after vitrectomy with 0.025% povidone iodine irrigation","fulltext":[{"header":"Background","content":"\u003cp\u003eBleb-related infections are a severe complication that can develop after mitomycin C-augmented trabeculectomy or trabeculectomy alone.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e They develop at a mean frequency of 6.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8 years after the surgery, and the 5-year cumulative incidence is 2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5%. This incidence is higher than that of infections after cataract surgery.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e The infections are classified into three stages.\u003csup\u003e\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e Stage I or blebitis is an infection confined to the bleb site with a mild cellular reaction in the anterior chamber. A Stage II infection affects mainly the anterior chamber and the vitreous is not involved. A Stage III infection involves the posterior part of the eye, and it is subdivided into Stage IIIa with mild involvement of the vitreous and Stage IIIb with more advanced involvement of the vitreous.\u003c/p\u003e \u003cp\u003eThe inflammation of the bleb (Stage III) can spread to the vitreous in 31.5% (46/146) of the eyes which causes a significant reduction of vision and an ekevatuib of the intraocular pressure (IOP) within 12 months.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Repeated intravitreal injections of antibiotics for Stage IIIa, and immediate vitreous surgery for Stage IIIb are recommended. In addition to the surgical removal of the infected vitreous, topical and intravitreal vancomycin (VCM) and ceftazidime (CAZ) are used as first-line treatments that have broad-spectrum antibacterial activity with a low potential for developing resistance.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eRecently, Nakashizuka and his colleagues reported that vitrectomy using an irrigation solution containing 0.025% povidone-iodine (PI) followed by postoperative antibiotics was safe and effective for the treatment of endogenous endophthalmitis and postoperative endophthalmitis including blebitis-related endophthalmitis.\u003csup\u003e\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e However, there are several reports on the toxicity of PI on the retina,\u003csup\u003e\u003cspan additionalcitationids=\"CR12 CR13\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e and only limited information is available on its safety in human eyes with severe endophthalmitis.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eElectroretinography (ERG) can be used to evaluate the physiology of the retina of the eye objectively\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, however the contact lens electrodes used to pick-up the ERGs can affect the filtering bleb. To overcome this problem, skin electrodes can be used to record the ERGs without affecting the filtering bleb and avoid the risk of infection.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWe present the results of pars plana vitrectomy (PPV) with irrigation of 0.025% PI in balanced salt solution (BSS) PLUS (Alcon Laboratories, Fort Worth, TX) in two cases of bleb-related endophthalmitis. The retinal function was evaluated by full-field ERGs recorded before and after the vitrectomy with irrigation containing PI.\u003c/p\u003e \u003cp\u003eThe procedures used on these patients were approved by the Ethics Committee of Saitama Medical University (No.2021-073), and the study was conducted in accordance with the tenets of the Declaration of Helsinki. A signed written informed consent was obtained from the two patients who participated in this study.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003e \u003cstrong\u003eCase 1\u003c/strong\u003e \u003cp\u003ewas a 46-year-old man who complained of ocular pain in his left eye in July of 202X. His best-corrected visual acuity (BCVA) in the left eye was 0.2 and the intraocular pressure (IOP) was 23.9 mmHg. He had been diagnosed with atopic keratoconjunctivitis which was treated with antibiotic and steroid eye drops, and steroid-induced glaucoma developed in his left eye. Trabeculectomy had been performed one month before our examination.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eOur slit-lamp examination showed conjunctival hyperemia, mild opacity of the superior cornea, and cells and mild flare in the anterior chamber \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The anterior vitreous opacification was mild, but the visibility of the fundus was poor. Clear optical coherence tomographic (OCT) images were not available.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA mild, filter bleb-associated endophthalmitis was suspected which was treated by intravitreal and subconjunctival injections of VCM, ceftazidime (CAZ), and frequent antibiotic eye drops. Examinations of the cultures of the secretions around the bleb were negative. Three days later, his BCVA decreased to hand movements at 0.5 meters, the fundus was not visible, and B-mode echography showed a high brightness area. He was diagnosed with an exacerbation of the endophthalmitis (Stage IIIb), He was treated with vitrectomy with VCM, CAZ, and 0.025% PI irrigation. One month after the surgery, the visual acuity improved to counting fingers at 0.5 meters.\u003c/p\u003e \u003cp\u003eFull-field ERGs were recorded pre- and postoperatively with the RETeval system (LKC Technologies, Gaithersburg, MD; Welch Allyn, Skaneateles Falls, New York, USA), a portable ERG device that uses skin electrodes and whose recording conditions conformed to the standards of the International Society for Clinical Electrophysiology of Vision (ISCEV).\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Comparisons of the pre- and postoperative ERGs showed an improvement of the a- and b-wave amplitudes and a stable b/a ratio of approximately 2.0 \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The implicit times of both waves did not change significantly.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCase 2\u003c/strong\u003e \u003cp\u003ewas a 63-year-old man who complained of ocular pain in his left eye on March, 202X. His BCVA in the left eye was hand movements at 0.5 meters, and the IOP was 15.0 mmHg. He had undergone phacovitrectomy for proliferative diabetic retinopathy (PDR) 11 years earlier and had undergone trabeculectomy for glaucoma of the left eye 5 years earlier.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eSlit-lamp examination showed conjunctival hyperemia, and cells and moderate flare in the anterior chamber \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Ophthalmoscopy showed mild vitreous opacity, and the OCT image was not clear but the retina could be seen to be atrophic probably due to the PDR. A bleb-associated endophthalmitis (Stage IIIa) was suspected.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIntravitreal injections of VCM and CAZ, frequent antibiotic eye drops, and subconjunctival injections of VCM and CAZ were performed. \u003cem\u003eKlebsiella pneumoniae\u003c/em\u003e was detected in the cultures of the secretions around the bleb. Three days later, the vitreous opacity worsened, and a high brightness area was observed in the B-mode echography images. A diagnosis of bleb-associated endophthalmitis (Stage IIIb) was made, and PPV with VCM, CAZ, and 0.025% PI irrigation was performed. The visual acuity recovered to 0.01 one month after the beginning of the treatments.\u003c/p\u003e \u003cp\u003eFull-field ERGs were recorded pre- and postoperatively with the RETeval system with the skin electrode. A comparison of the pre- and postoperative ERGs showed that the a- and b- wave amplitudes increased but the b/a ratio was not significantly changed at approximately 1.5 months postoperatively. The implicit times of both waves was also not significantly changed \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e"},{"header":"Discussion and Conclusions","content":"\u003cp\u003eThe microorganisms responsible for bleb-associated endophthalmitis can be identified in cultures but about 50% of cases are culture-negative. The most frequently detected organisms are members of the \u003cem\u003eStaphylococcus\u003c/em\u003e and \u003cem\u003eStreptococcus\u003c/em\u003e genus.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e PI acts directly on the membrane proteins of bacteria and viruses to inactivate them, and thus acts with or without drug resistance. The time for antimicrobial action is as short as 15 seconds at a 0.025% concentration.\u003csup\u003e8\u003c/sup\u003e \u003cem\u003eK. influenzae\u003c/em\u003e and \u003cem\u003eenterococci\u003c/em\u003e have also been detected in grade IIIb filtering bleb-related infections.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e There is also a report that VCM-resistant enterococci were detected as the causative pathogen of filtering bleb-related endophthalmitis.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eOur results showed that 0.025% PI irrigation in combination with antimicrobial perfusion can be effective in treating cases where the causative organism is not known or in cases where the organisms are drug-resistant. Because PI acts directly on the membrane proteins of bacteria and viruses to inactivate them, there is a low probability for microorganisms to become resistant to it. Another advantage of PI is the rapidity of its action.\u003c/p\u003e \u003cp\u003eIodine is known to be retinotoxic depending on its concentration which raises the possibility of retinal toxicity with its use.\u003csup\u003e\u003cspan additionalcitationids=\"CR12 CR13\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e In experiments on rabbits, PI at concentrations of 0.027% or lower showed no histological abnormalities to the intraocular tissues.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e Intravitreal administration of 0.1 mL of 1.25% PI and irrigation of the vitreous cavity with 0.025% PI for 15 minutes for endophthalmitis showed no decrease of retinal function on postoperative ERGs.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e In addition, there is only one report of two cases that used 0.025% PI combined with antibiotics in the irrigation solution during vitrectomy for filtering bleb-associated endophthalmitis.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e Unfortunately, the authors did not perform ERG recordings. In our two cases, there was no postoperative reduction of retinal function as shown by the ERGs as reported earlier.\u003c/p\u003e \u003cp\u003eThe presence of endophthalmitis has been determined by the visual acuity in most previous studies.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e Although perimetry and ERGs are helpful in assessing the function of the entire retina, there are only a small number of studies using these methods probably because of their inconvenience for the patients.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe RETeval system is a relatively new ERG recording system that uses skin electrodes and is less invasive.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e We showed that the ERGs recorded with a skin electrode can be used to evaluate the retinal function in the early postoperative period even in eyes after filtration surgery in which contact lenses and DTL electrodes cannot be used.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThese were only two cases, and the safety and effectiveness of this treatment cannot be applied to all cases because there are many factors that influence the presence of endophthalmitis. It is necessary to investigate a larger number of cases to determine whether a recurrence of endophthalmitis can be resolved and prevented by this method. Nevertheless, we believe that these findings will contribute to the establishment of a treatment protocol for bleb-associated endophthalmitis.\u003c/p\u003e \u003cp\u003eIn conclusion, vitrectomy with 0.025% PI irrigation is an effective and probably safe method to treat bleb-associated endophthalmitis. ERG recordings with skin electrodes can be used to evaluate the perioperative retinal function of bleb-associated endophthalmitis.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval and Consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was conducted according to the guidelines of the Declaration of Helsinki. The study protocol was approved by the Ethical Committee of Saitama Medical University (2021-073).\u0026nbsp;Written informed consent was obtained from participants after full explanation of the diagnosis and treatment.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Copies of the written consent are available for review by the Editor-in-Chief of this journal.\u003cbr\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of supporting data\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during the current study are included in this published article.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no conflicts of interest to declare.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Sources\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported in part by a grant to KS from the Japan Society for the Promotion of Science (JSPS; KAKENHI grant number: 22K09838).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions \u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eKoS, TaK, and KeS contributed to the study Concepts and Study Design; KoS, ToK, and TaK cared and examined patients; KoS and TaK were responsible for data acquisition; KoS, TaK, and KeS were responsible for data analysis; KoS and KeS were responsible for manuscript preparation and editing; KoS and TaK critically reviewed the manuscript. All authors agree to be accountable for all aspects of work. Patient anonymity is preserved. All authors attest that they meet the current ICMJE criteria for authorship.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank Professor Emeritus Duco Hamasaki of the Bascom Palmer Eye Institute for discussions and editing this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eYamamoto T, Sawada A, Mayama C, Araie M, Ohkubo S, Sugiyama K, et al. The 5-year incidence of bleb-related infection and its risk factors after filtering surgeries with adjunctive mitomycin C: collaborative bleb-related infection incidence and treatment study 2. Ophthalmology. 2014;121:1001\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSong A, Scott IU, Flynn HW, Flynn HW Jr, Budenz DL. 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Flicker electroretinograms before and after intravitreal ranibizumab injection in eyes with central retinal vein occlusion. Acta Ophthalmol. 2015;93:e465\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShibuya M, Yoshikawa Y, Katsumoto T, Shoji T, Kondo H, Miyakoshi H et al. Electroretinographic recordings with skin electrodes to assess effects of vitrectomy with gas tamponade on eyes with rhegmatogenous retinal detachment. Sci Rep 2019;9:19948. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1038/s41598-019-56307-z\u003c/span\u003e\u003cspan address=\"10.1038/s41598-019-56307-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTerauchi G, Shinoda K, Sakai H, Kawashima M, Matsumoto CS, Mizota A, et al. Retinal function determined by flicker ERGs before and soon after intravitreal injection of anti-VEGF agents. BMC Ophthalmol. 2019;19:129. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12886-019-1129-7\u003c/span\u003e\u003cspan address=\"10.1186/s12886-019-1129-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"blebitis, electroretinography, bleb-related endophthalmitis, povidone iodine irrigation, vitrectomy","lastPublishedDoi":"10.21203/rs.3.rs-3932930/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3932930/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eVitrectomy with 0.025% povidone-iodine (0.025% PI) in the irrigation solution was recently reported to be used to treat filtering bleb-associated endophthalmitis. However, iodine is known to be retinotoxic but it depends on its concentration. Electroretinography (ERGs) can be used to evaluate the retinal function, but the contact lens electrodes used to pick up the ERGs can affect the filtering bleb adversely. We performed ERGs with skin electrodes on eyes with bleb-associated endophthalmitis that had undergone vitrectomy with 0.025% PI irrigation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase presentation:\u003c/b\u003e\u003c/p\u003e \u003cp\u003eCase 1 was a 46-year-old man who underwent trabeculectomy for steroid induced glaucoma. One month postoperatively, a filtering bleb-associated endophthalmitis was suspected, and vitreal and subconjunctival injections of vancomycin (VCM) and ceftazidime (CAZ), and frequent antibiotic eye drops were started. After three days, an exacerbation of the endophthalmitis was observed and vitrectomy with 0.025% PI irrigation was performed. One month after the surgery, the visual acuity improved from hand movements to counting fingers. Pre- and postoperative ERGs recorded using skin electrodes showed an improvement in the a- and b-wave amplitudes and the b/a ratio was stable at approximately 2.0. Case 2 was a 63-year-old man who had undergone phacovitrectomy for proliferative diabetic retinopathy eleven years earlier and trabeculectomy for glaucoma five years earlier in the left eye. Five years after the surgery, the eye developed blebitis, and frequent antibiotic eye drops and subconjunctival injections of VCM and CAZ were performed. Three days later, vitreous opacities appeared and a high brightness area was observed in the B-mode echo images. A diagnosis of bleb-associated endophthalmitis was made, and vitrectomy with 0.025% PI irrigation was performed. The preoperative visual acuity was hand movements, and it improved to 0.01 one month after the surgery. Comparisons of the postoperative to the preoperative ERGs found that the a- and b- wave amplitudes increased and the b/a ratio was stable at approximately 1.5 postoperatively.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions\u003c/b\u003e\u003c/p\u003e \u003cp\u003eERG recordings with skin electrodes are helpful for evaluating postoperative retinal function in cases of bleb-associated endophthalmitis. Vitrectomy with 0.025% PI irrigation is effective and most likely safe for the treatment of bleb-associated endophthalmitis.\u003c/p\u003e","manuscriptTitle":"Electroretinographic evaluations of bleb-related endophthalmitis after vitrectomy with 0.025% povidone iodine irrigation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-13 18:51:05","doi":"10.21203/rs.3.rs-3932930/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5a01ba7a-53bc-46b8-beb0-111023629f3f","owner":[],"postedDate":"February 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-02-13T18:51:09+00:00","versionOfRecord":[],"versionCreatedAt":"2024-02-13 18:51:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3932930","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3932930","identity":"rs-3932930","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}