Eponymous Pupillary and Ocular Sensory Signs of Neurosyphilis: A Historical Review

The objective of this study was to review pupillary and ocular sensory signs historically associated with neurosyphilis, focusing on eponymous findings because they are the most traceable and consistently cited descriptors in the historical neuro-ophthalmic literature. These signs were originally described between 1850 and 1910 by five clinicians whose observations later received eponymous recognition. This study was designed as a narrative historical review supported by a structured search to ensure completeness. Only eponymous signs with established and consistent usage in the medical literature were included; purely descriptive or ambiguous terms were excluded. Searches were conducted and last updated on January 1, 2026, using PubMed/MEDLINE, Google Scholar, and major digitized archives (Gallica, HathiTrust, Internet Archive, and the Wellcome Collection). Search strategies in English, German, and French combined syphilis-related terms with the names of the relevant clinicians (Baillarger, Berger, Gowers, Haenel, and Saenger). Two reviewers independently screened the sources and extracted data on the eponym, year of description, primary reference, clinical features, and biographical background. Disagreements were resolved by consensus. Three signs involved characteristic pupillary abnormalities: unilateral mydriasis (Baillarger sign), an oval or elliptical pupil (Berger sign), and absent light reaction with a sluggish near response (Saenger sign). Two additional signs reflected sensory or autonomic involvement: diminished deep ocular sensation to digital pressure on the globe (Haenel sign) and non-specific pupillary oscillation (hippus) described by Gowers. Taken together, these findings show how clinicians attempted to localize autonomic and sensory deficits in neurosyphilis in the era before serologic testing. Although current diagnosis depends largely on serologic testing, neuroimaging, and established treatment protocols, knowledge of these historical neuro-ophthalmic signs remains clinically relevant. They can assist in identifying atypical or delayed cases and help illuminate the development of diagnostic thinking in neurosyphilis.