LAUSR

Dear Editor, Multiple evanescent white dot syndrome (MEWDS) is a unilateral inf lammatory chorioretinopathy characterized by multiple small white dots scattered at the posterior pole. It is a benign and self-limiting condition that usually occurs in healthy young women [1]. There is an ongoing global pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2. Herein we report a case of MEWDS as an ocular adverse effect after BNT162b2 messenger RNA (mRNA) COVID-19 vaccination (Pfizer Inc., Philadelphia, PA, USA). The patient provided written informed consent for the publication of the research details and clinical images. A 33-year-old healthy female patient visited a local clinic with a 1-day history of a steadily enlarging dark spot over her right central vision and metamorphopsia in the right eye. Notably, she had received her second dose of the BNT162b2 vaccine 6 days before symptom onset. In the right eye, fundus examination revealed multiple gray-white lesions at the posterior pole and nasal and temporal periphery, and optical coherence tomography (OCT) revealed a dome-shaped macula (DSM) with subretinal fluid and interruption of the ellipsoid zone (Fig. 1A, 1B). Two weeks later, the patient was referred to Severance Hospital. She revealed that the dark spot become slightly lighter 4 to 5 days after onset, but the metamorphopsia remained. The best-corrected visual acuity was 20 / 40 with spherical equivalents -10.12 diopter in the right eye. Fundus examination revealed regression of the small gray-white hyperautofluorescent lesions at the posterior pole and nasal and temporal periphery (Fig. 1C, 1D). OCT revealed a few vitreous cells, hyperreflective subfoveal material without fluid, and ellipsoid zone disruption (Fig. 1E). Early-phase f luorescein angiography revealed multiple hyperf luorescent dots in a wreath-like pattern, while late-phase indocyanine green angiography revealed hypofluorescent dots in areas corresponding to the autofluorescent fundus lesions (Fig. 1F, 1G). The 30-2 Humphrey visual field test (Humphrey, San Leandro, CA, USA) showed enlargement of the blind spot (Fig. 1H). Choroidal neovascularization was not evident on OCT angiography (Fig. 1I). With the diagnosis of MEWDS, she was prescribed 15 mg of oral prednisone per day, which was tapered over 2 weeks. Additionally, she was administered intravitreal bevacizumab (Avastin, 1.25 mg/0.05 mL; Genentech, South San Francisco, CA, USA) in hopes of hastening her recovery. Ten weeks later, her symptoms improved with increased visual acuity to 20 / 50. The fundus lesions resolved further, but subfoveal hyperreflective material was still observed on OCT (Fig. 1J, 1K). Recent case studies have shown that MEWDS can occur or recur within a month of COVID-19 vaccination [1,2]. The cause of MEWDS is unknown; both infectious and immune-mediated origins have been proposed. The presence of antecedent f lu-like symptoms in approximately half of all affected patients supports an infectious origin [3]. However, the presence of increased levels of circulating immunoglobulins in the acute phase [4] and the occurrence of MEWDS af ter vaccination support an immune-mediated origin. Vaccine-associated inf lammation has been thought to occur via molecular mimicry, direct antigen-mediated cellular and/or humoral immune response, adjuvant-mediated immune response, or activation of common and/or specific loci in genetically predisposed individuals [1]. The COVID-19 vaccine generates the viral spike protein. Therefore, the spike proteins themselves or immune reactions elicited by their presence could trigger inflammatory reactions that could lead to MEWDS. Administration of mRNA vaccines such as the BNT162b2 vaccine can lead to upregulation of type 1 interferon secretion, resulting in an autoimmune response in susceptible Korean J Ophthalmol 2022;36(5):471-473 https://doi.org/10.3341/kjo.2022.0077