Small, irregular pupils that exhibit “light-near” dissociation (react poorly or not at all to light but constrict normally during accommodation/convergence). By definition, vision must be intact.
The pupils dilate poorly in darkness. Always bilateral, although may be asymmetric.
Differential Diagnosis of “Light-Near” Dissociation
Bilateral optic neuropathy or severe retinopathy: Reduced visual acuity with normal pupil size.
Adie (tonic) pupil: Unilateral or bilateral irregularly dilated pupil that constricts slowly and unevenly to light. Normal vision. See 10.4, Adie (Tonic) Pupil.
Dorsal midbrain (Parinaud) syndrome: Associated with eyelid retraction (Collier sign), supranuclear upgaze palsy, and convergence retraction nystagmus. See 10.4, Adie (Tonic) Pupil and “Acquired Forms of Nystagmus” in 10.21, Nystagmus.
Rarely caused by third cranial nerve palsy with aberrant regeneration. See 10.6, Aberrant Regeneration of the Third Cranial Nerve.
Test the pupillary reaction to light and convergence: To test the reaction to convergence, patients are asked to look first at a distant target and then at their own finger, which the examiner holds in front of them and slowly brings in toward their face.
Slit-lamp examination: Look for interstitial keratitis (see 4.18, Interstitial Keratitis).
Dilated fundus examination: Search for chorioretinitis, papillitis, and uveitis.
Fluorescent treponemal antibody absorption (FTA-ABS) or treponemal-specific assay (e.g., microhemagglutination assay–Treponema pallidum [MHA-TP]) and rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test.
If the diagnosis of syphilis is established, lumbar puncture (LP) may be indicated. See 12.10, Syphilis, for specific indications.
Treatment is based on the presence of active disease and previous appropriate treatment.
See 12.10, Syphilis, for treatment indications and specific antibiotic therapy.