Yes, you can get syphilis of the eye – professor of ophthalmology explains

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A cluster of cases of ocular syphilis has been reported in Michigan, US. The five women infected all contracted the disease from the same sexual partner.

While ocular syphilis is not that common overall, accounting for 1% of all syphilis cases this probably represents an underestimate of its prevalence.

Why is this important? Ocular syphilis has been described as the great imitator. It can manifest in a multitude of ways and as such the diagnosis can be missed. This is important because it can easily be treated and cured.

Untreated, it can progress over many years causing more damage to multiple organ systems. It is a tragedy if missed. It can affect virtually every tissue in the eye. This includes the cornea, the iris, the orbit, the eyelids, the retina, the optic nerve and the sclera. It usually presents as an inflammation, but sometimes the presentation is more subtle.

An anatomy diagram showing parts of the human eye.
Parts of the eye. ImagineDesign/Shutterstock

If syphilis is missed, other important treatable infections may also be missed. For example, HIV infection is also common in patients with syphilis. HIV infection can accelerate the progression of ocular syphilis. Missing an ocular syphilis diagnosis might mean missing an HIV diagnosis too and, again, not treating a treatable disease.

The five women described in Michigan, all infected by the same man, illustrate this point as they had different signs and symptoms, ranging from inflammation in the eye through to paralysis of cranial nerves. In these acute cases, thankfully, a correct diagnosis was promptly made and treatment started.

But sometimes ocular syphilis is not diagnosed and a slow grumbling infection can occur in the retina. This may resemble an inherited eye condition called retinitis pigmentosa.

So a patient may be told there is nothing that can be done as they are thought to have a genetic eye disease and their sight can be left to deteriorate. They may develop further syphilitic complications, such as syphilis affecting the brain.

Still very prevalent today

In my own practice, I have “cured” several incurable cases of retinitis pigmentosa because I tested for syphilis and found that the patient actually had ocular syphilis. So it is important to be aware that sexually transmitted infections are increasing.

Syphilis is caused by a bacterium called Treponema pallidum. It is thought of as an old disease – possibly introduced to Europe by Christopher Columbus in 1493 – but it is still very prevalent today. Syphilis infections in the UK increased to 8,692 in 2022, up 15% compared with 2021 (7,543). This is the largest number of confirmed infections since 1948.

Doctors must not be shy in testing for it and explaining to patients why it is necessary to do so. In my experience, patients are happy to be tested as it offers the potential to cure their eye condition.

The message from these Michigan cases is that syphilis is increasing as a sexually transmitted disease. It can affect multiple organs including the eye. It can be missed and doctors should always think of the “great imitator” and not be shy in testing for it. If detected, it can be swiftly treated with antibiotics, which is not the case with many other eye diseases.

The Conversation

Andrew Lotery does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.