Monkeypox as an emerging infectious disease: the ophthalmic implications

The 2022 outbreak of monkeypox is of worldwide significance. There has been a rapid escalation in case numbers despite efforts to contain it and the WHO has declared it a Public Health Emergency of International Concern. To date, over 51 257 laboratory-confirmed cases have been reported, the majority in non-endemic countries, with 3279 in the UK. It is vital for ophthalmologists to understand this disease and the risk it poses. Human monkeypox is a zoonotic disease caused by the monkeypox virus, a double-stranded DNA virus in the Orthopoxvirus genus of the Poxviridae family. Other orthopoxviruses include variola (smallpox), cowpox and vaccinia; all of which have significant ocular sequelae. Transmission occurs from an animal reservoir (unknown, likely rodents) to a human host, leading to secondary human-to-human spread. During the recent outbreak, a higher incidence has been found in gay, bisexual or other men who have sex with men. Clinical diagnosis may be challenging as presentation can mimic common ophthalmic diseases. A thorough history is key to identifying potential cases. Ophthalmic manifestations may include preseptal cellulitis, conjunctivitis and keratitis. The oral antiviral agent tecovirimat, which was developed to treat smallpox, is the mainstay of treatment. Trifluorothymidine (trifluridine) eye-drops can be used for ophthalmic involvement. In addition, smallpox vaccines have provided some cross-immunity. Ocular monkeypox should be managed by infectious diseases specialists, in consultation with ophthalmologists to provide the expertise needed to treat potentially vision-threatening complications. This outbreak highlights the need for healthcare providers to implement appropriate infection control measures and be familiar with the identification and treatment of both cutaneous and ocular disease.