Primary multiple evanescent white dot syndrome and multiple evanescent white dot syndrome secondary to multifocal choroiditis/punctate inner choroidopathy

To present and compare the clinical features and multimodal imaging (MMI) findings of the primary form of multiple evanescent white dot syndrome (MEWDS) and MEWDS secondary to multifocal choroiditis/punctate inner choroidopathy (MFC/PIC).A prospective case series. Thirty eyes of 30 MEWDS patients were included and divided into the primary MEWDS group and MEWDS secondary to MFC/PIC group. Demographic, epidemiologic, and clinical characteristics and MEWDS-related MMI findings of the two groups were compared.Seventeen eyes from 17 patients with primary MEWDS and 13 eyes from 13 patients with MEWDS secondary to MFC/PIC were evaluated. Patients with MEWDS secondary to MFC/PIC tended to have a higher degree of myopia than those with primary MEWDS. No other significant differences in demographic, epidemiologic, and clinical characteristics and MMI findings were found between the two groups."MEWDS-like reaction" hypothesis seems to be correct for MEWDS secondary to MFC/PIC, and the authors highlight the importance of MMI examinations in MEWDS. Further research is needed to confirm whether the hypothesis is applicable to other forms of secondary MEWDS.