Which Light Near Dissociation condition is MOST associated with a decreased deep tendon reflex?

• A. Argyll Robertson Pupil
• B. Tonic Pupil
• C. Adie's Pupil
• D. Horner's Syndrome

Answer: (B)

Light near dissociation refers to a pupil that doesn’t respond well to light but can still constrict with near effort or accommodation. The condition most linked with a decrease in deep tendon reflexes is the tonic pupil, classic of Holmes-Adie syndrome. In this situation, the pupil is enlarged and poorly reactive to light, often with sluggish or reduced accommodation. The distinctive feature is autonomic and sensory involvement that extends beyond the eye, producing diminished or absent deep tendon reflexes, especially in the legs, due to a postganglionic parasympathetic and dorsal root ganglion neuropathy. Argyll Robertson pupils also show light–near dissociation but are associated with syphilis and don’t typically feature reflex loss. Horner’s syndrome presents with ptosis and miosis and does not produce the same light–near dissociation pattern or reflex changes. So the tonic pupil best fits the association with decreased deep tendon reflexes.