Diagnosis and the Pilocarpine Test

The diagnosis of Holmes-Adie Syndrome (HAS) is primarily clinical, meaning a specialist—typically a neuro-ophthalmologist—can often identify it through a physical exam and a specific bedside test ^[1][2]. Because an enlarged pupil can sometimes be a sign of a more serious neurological issue, the diagnostic process is designed to confirm HAS while ruling out other possibilities ^[3][4].

The Dilute Pilocarpine Test

The most definitive tool for diagnosing an Adie’s tonic pupil is the dilute pilocarpine test ^[5][6]. This test relies on a biological phenomenon called denervation supersensitivity ^[5][4].

What is Denervation Supersensitivity?

When the nerves that normally control your pupil (the ciliary ganglion) are damaged, the muscles in the iris (the colored part of your eye) become “starved” for their usual chemical signals ^[7][8]. In response, these muscles become incredibly sensitive to even tiny amounts of those chemicals ^[5]. It is as if the muscle is “listening” extra hard for a signal it hasn’t heard in a long time.

How the Test Works

1. Preparation: The doctor measures your pupils in both bright and dim light.
2. The Drops: A very weak solution of pilocarpine (usually a concentration of 0.0625% to 0.125%) is placed in both eyes ^[5][3].
3. The Wait: You wait about 30 to 60 minutes for the drops to take effect.
4. The Result:
   • Normal Pupil: A healthy pupil will not react to such a low concentration of the drug.
   • Adie’s Pupil: Because of denervation supersensitivity, the affected pupil will constrict (shrink) significantly ^[5][4].

Note on Test Experience: The drops themselves may temporarily cause blurry vision or a mild brow ache during the test, which is completely normal and will fade.

Recent research suggests that the lower concentration of 0.0625% may actually be more accurate for confirming the diagnosis than the slightly stronger 0.125% solution ^[5]. In some clinics, doctors may also use digital pupillometry, a specialized camera that takes precise measurements of how your pupil reacts ^[5].

Completeness Checklist: Ruling Out Underlying Causes

While HAS is most often idiopathic (having no known cause), a thorough diagnosis involves checking for underlying triggers to ensure there isn’t a broader systemic issue ^[7][1]. Your care team may suggest the following screenings:

• [ ] Viral History: Your doctor should ask about recent infections, including COVID-19, which has been linked to the sudden onset of Adie’s symptoms ^[9][10].
• [ ] Autoimmune Markers: If you have symptoms like dry eyes or dry mouth, tests for Sjögren’s syndrome (SSA/SSB antibodies) or lupus (ANA) may be recommended ^[7][11].
• [ ] Syphilis Serology: Blood tests (like RPR or FTA-ABS) are standard because syphilis is a well-known, treatable cause of tonic pupils ^[7][12].
• [ ] Neurological Imaging: In some cases, an MRI of the brain or eye sockets (orbits) may be performed to ensure no physical structures are pressing on the nerves ^[3][2].
• [ ] Paraneoplastic Screening: In highly unusual cases where symptoms are rapidly progressive or accompanied by widespread neurological issues, doctors may test for paraneoplastic syndromes (an immune response to a hidden tumor) ^[13][14]. Please note: This is exceptionally rare. Doctors run these specific tests out of an abundance of caution to be absolutely thorough, not because a tumor is likely.

By performing these tests, your doctor can move from a “suspected” case to a “confirmed” diagnosis of Holmes-Adie Syndrome. For what to do next, see the Management, Treatment & Quality of Life page.