One of the ocular manifestations of syphilis is syphilitic perineuritis.
Pathogenesis: inflammation restricted to the optic nerve sheath
Clinical features:
(1) asymptomatic, without pain or headache
(2) normal visual acuity
(3) enlarged blind spot
(4) constricted peripheral field
(5) normal or slightly swollen optic disc
(6) normal lumbar CSF opening pressure
On MRI the optic nerve sheath and orbital fat show enhancement
The inflammation should resolve after specific antibiotic therapy.