The role of ophthalmologic assessment in detecting ocular syphilis

Background: Ocular syphilis incidence has increased worldwide over the past decade. Diagnosis is challenging due to undisclosed risk factors. Purpose: To characterize demographics, risk factors, clinical presentations, treatments, and outcomes for ocular syphilis cases to inform timely diagnosis and management strategies. Methods: This is a retrospective case series that evaluated patients with ocular syphilis at three tertiary care hospitals in London, Ontario, Canada, to characterize sexually transmitted infection risk factors, stage of syphilis at diagnosis, presenting ocular symptoms, rapid plasma reagin (RPR) titres, ophthalmologic findings, and visual acuity. Results: Among 47 cases with a total of 78 affected eyes, bilateral ocular involvement was 31 (66%), the median age was 52 years, 33/47 (70%) were male, and 14/33 (42%) of males identified as gay or bisexual men who have sex with men (GBMSM). HIV co-infection was identified in 8/46 (17%) with known HIV status. RPR titres were ≥1:64 in 41/47 (87%). Ocular findings included uveitis in 66/78 (85%), panuveitis in 27/78 (35%), and optic neuropathy in 21/78 (27%) of affected eyes. Mean visual acuity at diagnosis was 0.57 logMAR, which improved to 0.31 logMAR after treatment. The diagnosis of syphilis was first made by an ophthalmologist in 38/47 (81%) of ocular syphilis cases, and in 28/38 (74%) of these cases, risk factors were not disclosed before diagnosis. Conclusion: Our findings support routine syphilis serology testing in patients presenting with uveitis or optic neuropathy, regardless of disclosed sexual risk factors. Ophthalmologists established the initial diagnosis in 81% of ocular syphilis cases, despite patients not disclosing sexually transmitted infection risk factors. The findings of this study support the need for routine syphilis testing in patients presenting with unexplained uveitis or optic neuropathy.