Background/aims To determine the incidence and causative pathogens of endophthalmitis after vitrectomy during strict face mask wearing in the COVID-19 period. Methods This was a retrospective multicentre study including 31 ophthalmological institutions of the Japanese Retina and Vitreous Society or Japan-Clinical Retina Study group. Patients who had undergone vitrectomy during 2019, the pre-COVID-19 period, and from July 2020 to June 2021, the COVID-mask period, were studied. The results of cataract surgery were used as a control. The total number of vitrectomies and the total number of postoperative endophthalmitis were determined. Then, the differences in the incidence of postoperative endophthalmitis between the pre-COVID-19 period and the COVID-mask period, and the type of pathogens causing the endophthalmitis were studied. Results The incidence of postvitrectomy endophthalmitis was significantly lower in the pre-COVID-19 period with 16 568 surgeries and 18 endophthalmitis cases (0.11%) than in the COVID-mask period of 14 929 surgeries and 31 endophthalmitis cases (0.21%; p=0.031, OR=1.913, 95% CI 1.078 to 3.394). In the pre-COVID-19 period, 4 of the 18 eyes were culture positive, and all were of the Staphylococcus family. In the COVID-mask period, 9 of the 31 eyes were culture positive, and 4 cases were related to oral commensals including Streptococcus spp, which are reportedly very rare in endophthalmitis after vitrectomy. Conclusions It is necessary for physicians to be aware of the higher incidence of postvitrectomy endophthalmitis during the COVID-mask period, and to treat their patients appropriately. Data are available upon reasonable request.

中文翻译：

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相对于 COVID-19 大流行期间佩戴口罩，玻璃体切除术后眼内炎的发生率增加

背景/目的 确定在 COVID-19 期间严格佩戴口罩期间玻璃体切除术后眼内炎的发病率和致病病原体。方法这是一项回顾性多中心研究，包括日本视网膜和玻璃体学会或日本临床视网膜研究组的 31 家眼科机构。研究对象是在 2019 年（COVID-19 之前）以及 2020 年 7 月至 2021 年 6 月（COVID-mask 期间）接受过玻璃体切除术的患者。白内障手术的结果用作对照。确定玻璃体切除术总数和术后眼内炎总数。然后，研究了COVID-19之前时期和COVID-mask时期术后眼内炎发生率的差异，以及引起眼内炎的病原体类型。结果 在 COVID-19 之前的时期，玻璃体切除术后眼内炎的发生率显着降低，其中有 16 568 例手术和 18 例眼内炎病例（0.11%），而在 COVID-19 期间的 14 929 例手术和 31 例眼内炎病例（0.21%；p= 0.031，OR=1.913，95% CI 1.078 至 3.394）。在 COVID-19 之前的时期，18 只眼睛中有 4 只眼睛培养呈阳性，并且全部属于葡萄球菌家族。在戴口罩期间，31只眼睛中有9只眼睛培养呈阳性，其中4例与包括链球菌在内的口腔共生菌有关，据报道，这种细菌在玻璃体切除术后的眼内炎中非常罕见。结论 医生有必要认识到新冠肺炎期间玻璃体切除术后眼内炎的发生率较高，并适当治疗患者。数据可根据合理要求提供。