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• Response to Dr Velez-Montoya and colleagues' comment
  Taiji Sakamoto
  Published on: 21 September 2023
• Increased incidence of endophthalmitis after vitrectomy relative to face mask wearing during COVID-19 pandemic
  Raul Velez-Montoya, Jorge I. Soberanes-Perez, Kingston Ureña-Wong, Manuela Franco-Sanchez and Jans Fromow-Guerra
  Published on: 21 September 2023

• Published on: 21 September 2023

  Response to Dr Velez-Montoya and colleagues' comment

  • Taiji Sakamoto, Professor Kagoshima University, Kagoshima, Japan

  To the Editor:

  We thank Dr Velez-Montoya and colleagues for their interest in our study.1 We reported that there was an increase in the prevalence of endophthalmitis after vitrectomy in Japan and found that it was probably related to the face masks during the COVID period.2 Although the cause for the increase definitively determined, we need to report these findings to the ophthalmologic community to alert them of this possibility.

  First, we address the indicated point, “the definition of postoperative endophthalmitis was not rigorous”. We used the definition of the Endophthalmitis Vitrectomy Study group.3 Although this definition is relatively old, many subsequent studies have used it, and it has the advantage that our findings could be compared to these other studies with the same definition.

  They also stated that the latest studies have shown that the sclerotomies after a pars plana vitrectomy seal within 15 days after the surgery even after a suture-less closure. Thus, the site of the incision was unlikely the entry port for the infectious micro-organisms after that time. This is generally true but the cause of infectious endophthalmitis after vitrectomy is complex. Because the cause of infectious endophthalmitis is varied, it is not surprising that anything can happen with postoperative endophthalmitis. For example, it is possible for a patient to inadvertently touch the eye in the early postoperative period and cause the incision to open. Once...

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  To the Editor:

  We thank Dr Velez-Montoya and colleagues for their interest in our study.1 We reported that there was an increase in the prevalence of endophthalmitis after vitrectomy in Japan and found that it was probably related to the face masks during the COVID period.2 Although the cause for the increase definitively determined, we need to report these findings to the ophthalmologic community to alert them of this possibility.

  First, we address the indicated point, “the definition of postoperative endophthalmitis was not rigorous”. We used the definition of the Endophthalmitis Vitrectomy Study group.3 Although this definition is relatively old, many subsequent studies have used it, and it has the advantage that our findings could be compared to these other studies with the same definition.

  They also stated that the latest studies have shown that the sclerotomies after a pars plana vitrectomy seal within 15 days after the surgery even after a suture-less closure. Thus, the site of the incision was unlikely the entry port for the infectious micro-organisms after that time. This is generally true but the cause of infectious endophthalmitis after vitrectomy is complex. Because the cause of infectious endophthalmitis is varied, it is not surprising that anything can happen with postoperative endophthalmitis. For example, it is possible for a patient to inadvertently touch the eye in the early postoperative period and cause the incision to open. Once opened, the scleral wound becomes a point of entry for infectious organisms. Additionally, the vitreous wick syndrome has been reported to occur especially after sutureless vitrectomy.4 Exposure to oral bacteria through masks can also result in infections. Considering the fatigue of the surgical team (human error) at the peak of the COVID epidemic, it is understandable that the source of infection most likely was during the vitrectomy. Nevertheless, other possibilities must be considered. Thus, the present definition of endophthalmitis, even in cases of infection after 42 days, is meaningful

  Second, it is fair to point out that bacteria such as Streptococcus mitis are usually low pathogenic or opportunistic pathogens. However, S. mitis was the second most common organism found in cultures in post vitrectomy endophthalmitis.5 Exposure to exhaled air containing endemic oral bacteria for more than a certain amount of time can cause this.

  Third, regarding Velez-Montoya and colleagues’ statement, “the results observed for the prevalence of postoperative endophthalmitis in the phacoemulsification-only group is not consistent with the main hypothesis”. We explained these findings as follows in the original paper. There was no difference in the frequency of endophthalmitis after cataract surgery before and after the masking period. Cataract surgery and vitreous surgery are different procedures. The incidence of endophthalmitis was significantly higher after vitrectomy, even when exposed to the same species and dosages.2 It is because the defense system against pathogenic microorganisms is weaker in the vitreous than in the anterior chamber.6 This is possibly the reason why an increase was detected only in the post-vitrectomy cases. This may also be related to the fact that the concentration of bacteria around the eye was somewhat increased by the strict mask wearing. This explains our finding that the incidence of endophthalmitis is the same in cataract surgery before and during COVID19-mask period, but is higher in vitrectomy during the COVID19-mask period. This is consistent with our assumption that the masked period is associated with a higher incidence of infective endophthalmitis after vitrectomy.

  We again thank Dr Velez-Montoya and colleagues for their advice and the British Journal of Ophthalmology for providing us with a space to share our comments with the medical community.

  References

  1. Velez-Montoya, Raul, et al. Letter to the editor on "Increased incidence of endophthalmitis after vitrectomy relative to face mask wearing during COVID-19 pandemic.". Brit J Ophthalmol 2023
  2. Sakamoto T, Terasaki H, Yamashita T, Shiihara H, Funatsu R, Uemura A; Japanese Retina and Vitreous Society. Increased incidence of endophthalmitis after vitrectomy relative to face mask wearing during COVID-19 pandemic. Br J Ophthalmol. 2022 Jun 21:bjophthalmol-2022-321357. doi: 10.1136/bjophthalmol-2022-321357. Epub ahead of print. PMID: 35728937.
  3. Results of the Endophthalmitis Vitrectomy Study. A randomized trial of immediate vitrectomy and of intravenous antibiotics for the treatment of postoperative bacterial endophthalmitis. Endophthalmitis Vitrectomy Study Group. Arch Ophthalmol. 1995;113:1479-1496.
  4. Venkatesh P, Verma L, Tewari H. Posterior vitreous wick syndrome: a potential cause of endophthalmitis following vitreo-retinal surgery. Med Hypotheses. 2002 Jun;58(6):513-5. doi: 10.1054/mehy.2001.1490. PMID: 12323120.
  5. Li AL, Wykoff CC, Wang R, Chen E, Benz MS, Fish RH, Wong TP, Major JC Jr, Brown DM, Schefler AC, Kim RY, OʼMalley RE. Endophthalmitis after intravitreal injection: Role of Prophylactic Topical Ophthalmic Antibiotics. Retina. 2016 Jul;36(7):1349-56. doi: 10.1097/IAE.0000000000000901. PMID: 26655622.
  6. Shockley RK, Jay WM, Fishman PH, Aziz MZ, Rissing JP. Effect of inoculum size on the induction of endophthalmitis in aphakic rabbit eyes. Acta Ophthalmol (Copenh). 1985;63:35-38.

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  Conflict of Interest:
  None declared.

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• Published on: 21 September 2023

  Increased incidence of endophthalmitis after vitrectomy relative to face mask wearing during COVID-19 pandemic

  • Raul Velez-Montoya, Retina Surgeon Retina Division. Asociación para Evitar le Ceguera en México IAP. México City. 04030 México
  • Other Contributors:
    • Jorge I. Soberanes-Perez, Retina Fellow
    • Kingston Ureña-Wong, Retina Fellow
    • Manuela Franco-Sanchez, Retina Fellow
    • Jans Fromow-Guerra, Retina Surgeon

  Dear Editor.

  We read with interest the manuscript published by Sakamoto et al, on behalf of the Japanese Retina and Vitreous Society, titled: Increased incidence of endophthalmitis after vitrectomy relative to face mask-wearing during COVID-19 pandemic”.[1] In this manuscript, the authors discuss their results after comparing the total prevalence of infectious endophthalmitis among patients that underwent ocular surgery, before and after the peak of the SARS-CoV-2 pandemic in Japan.[1] The authors should be commended due to the level of complexity and significant effort needed to coordinate several centers simultaneously, as well as the detailed description provided in the manuscript regarding the clinical presentation, microbiological results, and outcomes of all cases. Interestingly and despite the low rate of positive vitreous cultures, the authors were able to isolate oral bacteria among several of the cases that developed endophthalmitis during the pandemic, including one caused by Staphylococcus lugdunensis; a pathogen typically hard to eliminate with mechanical washing bacteria, because it accumulates behind the auricle.[1] With all this evidence, the authors provided a compelling argument regarding the inappropriate wearing of face masks could increase the risk of postoperative endophthalmitis. Nevertheless, we believe that there are a few important considerations that the authors may need to address before making such an assumption.
  As a start, we ca...

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  Dear Editor.

  We read with interest the manuscript published by Sakamoto et al, on behalf of the Japanese Retina and Vitreous Society, titled: Increased incidence of endophthalmitis after vitrectomy relative to face mask-wearing during COVID-19 pandemic”.[1] In this manuscript, the authors discuss their results after comparing the total prevalence of infectious endophthalmitis among patients that underwent ocular surgery, before and after the peak of the SARS-CoV-2 pandemic in Japan.[1] The authors should be commended due to the level of complexity and significant effort needed to coordinate several centers simultaneously, as well as the detailed description provided in the manuscript regarding the clinical presentation, microbiological results, and outcomes of all cases. Interestingly and despite the low rate of positive vitreous cultures, the authors were able to isolate oral bacteria among several of the cases that developed endophthalmitis during the pandemic, including one caused by Staphylococcus lugdunensis; a pathogen typically hard to eliminate with mechanical washing bacteria, because it accumulates behind the auricle.[1] With all this evidence, the authors provided a compelling argument regarding the inappropriate wearing of face masks could increase the risk of postoperative endophthalmitis. Nevertheless, we believe that there are a few important considerations that the authors may need to address before making such an assumption.
  As a start, we can mention a few methodological irregularities that are hallmarks of any retrospective study and thus unavoidable. However, some may carry a significant relevance to the outcome such as the lack of rigor in the definition of postoperative endophthalmitis in the inclusion/exclusion criteria. In their manuscript, Sakamoto et al considered postoperative endophthalmitis, any intraocular infection that developed within 42 days after surgery. Although we agree with this definition, we must clarify that this definition refers to the maximum time elapsed between the invasion of the intraocular space by the offending bacteria, which is during surgery, and the development of the first clinical symptoms. Which, depending on the bacteria's virulence, could be up to 6 weeks. The latest optical coherence tomography and ultrasound biomicroscopy evidence have shown that sclerotomies after a pars plana vitrectomy seal between 8 and 15 days after surgery, even after a sutureless approach.[2 3] Therefore, it is highly unlikely that the source of infection originated after this time, as the authors seem to imply. Moreover, although the authors’ argument that face masking may increase the contamination of the periocular area makes sense, laboratory evidence has shown that there is no difference between bacterial dispersion toward the ocular surface when comparing different types of masks and masking techniques (tape in the superior border of the mask and no tape).[4] Nevertheless, we do agree that wearing a face mask before or during surgery may induce ocular surface changes such as dry eye disease and subclinical infectious keratitis, which might hypothetically increase the risk of endophthalmitis. If we consider the possible exhaustion of the surgical team (human error), scarcity of surgical disinfectants, and other factors that occurred during the peak of the SARS-CoV-2 pandemic, this should place the source of the infection during surgery and not after it. The high prevalence of Streptococcal endophthalmitis in the SARS-CoV-2 mask period (as defined by the authors), supports indeed the notion that contamination may come from the oral flora, very similar to the reports of post intravitreal injection endophthalmitis. However, bacteria such as Streptococcus mitis and Streptococcus salivarius are usually described as low-virulence or opportunistic pathogens. Therefore, the onset time of the clinical symptoms of endophthalmitis, information not described in the manuscript, could have helped the reader to infer if the contamination occurred during surgery or during the postoperative time.
  Finally, the result observed regarding the prevalence of postoperative endophthalmitis in the only-phacoemulsification group, is not consistent with the main hypothesis suggested by the authors, and points in the opposite direction. If how the patient uses the mask during the postoperative period is indeed a determinant factor in endophthalmitis development and, considering that the prevalence of endophthalmitis after vitrectomy is usually lower in comparison to other surgical procedures [5]; we should have expected a proportional increase in the prevalence in all three groups. The latter might be the result of a lack of a sample calculation and therefore an error type 1, which should have been mentioned in the limitation section. A throughout analysis of the surgical circumstance per group is also lacking. Consequently, it is not clear at this time if other significant risk factors (trauma, intraocular foreign body, posterior capsule rupture) for endophthalmitis were present or not during surgery. A multivariate analysis, controlling for several other risk factors should be enough to shed light on this matter.
  We congratulate Sakamoto et al for this outstanding contribution. We will look forward to their reply.

  References:
  1. Sakamoto T, Terasaki H, Yamashita T, et al. Increased incidence of endophthalmitis after vitrectomy relative to face mask wearing during COVID-19 pandemic. Br J Ophthalmol 2022 doi: 10.1136/bjophthalmol-2022-321357[published Online First: Epub Date]|.
  2. Keshavamurthy R, Venkatesh P, Garg S. Ultrasound biomicroscopy findings of 25 G Transconjuctival Sutureless (TSV) and conventional (20G) pars plana sclerotomy in the same patient. BMC Ophthalmol 2006;6:7 doi: 10.1186/1471-2415-6-7[published Online First: Epub Date]|.
  3. Sawada T, Kakinoki M, Sawada O, Kawamura H, Ohji M. Closure of sclerotomies after 25- and 23-gauge transconjunctival sutureless pars plana vitrectomy evaluated by optical coherence tomography. Ophthalmic Res 2011;45(3):122-8 doi: 10.1159/000318875[published Online First: Epub Date]|.
  4. Angaramo S, Law JC, Maris AS, et al. Potential impact of oral flora dispersal on patients wearing face masks when undergoing ophthalmologic procedures. BMJ Open Ophthalmol 2021;6(1):e000804 doi: 10.1136/bmjophth-2021-000804[published Online First: Epub Date]|.
  5. AlBloushi B, Mura M, Khandekar R, et al. Endophthalmitis Post Pars Plana Vitrectomy Surgery: Incidence, Organisms' Profile, and Management Outcome in a Tertiary Eye Hospital in Saudi Arabia. Middle East Afr J Ophthalmol 2021;28(1):1-5 doi: 10.4103/meajo.MEAJO_424_20[published Online First: Epub Date]|.

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  Conflict of Interest:
  None declared.

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