Footnotes

• Handling editor Josef S Smolen

• Twitter @NA

• Contributors GZ, XZ and HW contributed equally to this work. GZ examinedthe patient as the attending physician. SZ performed ophthalmological examinations. GZ and HW wrote the manuscript. HW and XZ supervised the study. All authors contributed to discussion and approved the final version.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient consent for publication Not required.

• Provenance and peer review Not commissioned; externally peer reviewed.