ABO Neuro-Ophthalmology and Orbit 2

Question 1

In the Optic Neuritis Treatment Trial, what was the main effect of IV methylprednisolone followed by oral prednisone compared with placebo?

Accepted Answer

Faster visual recovery without better long-term visual outcome

Answer

IV steroids sped up recovery but did not change final visual acuity, and the lower MS risk they showed did not last past about 2-3 years.

Question 2

Which ONTT treatment arm was associated with an increased rate of recurrent optic neuritis?

Accepted Answer

Oral prednisone alone at standard dose

Answer

Oral prednisone alone (1 mg/kg/day) increased the risk of new optic neuritis attacks, so it is avoided as monotherapy.

Question 3

A patient has a large pupil with segmental iris sphincter palsy, light-near dissociation, and tonic redilation. Which agent best confirms the diagnosis?

Accepted Answer

Dilute pilocarpine 0.1%

Answer

A tonic (Adie) pupil shows cholinergic denervation supersensitivity and constricts to dilute pilocarpine.

Question 4

In a patient with confirmed Horner syndrome, hydroxyamphetamine 1% fails to dilate the affected pupil. Where is the lesion?

Accepted Answer

Third-order (postganglionic) neuron

Answer

Hydroxyamphetamine releases norepinephrine from intact postganglionic terminals, so failure to dilate indicates a third-order lesion.

Question 5

Why does apraclonidine 0.5% reverse the anisocoria in Horner syndrome?

Accepted Answer

Denervation supersensitivity of alpha-1 receptors in the iris dilator

Answer

Apraclonidine's weak alpha-1 activity dilates the supersensitive denervated pupil, which reverses the anisocoria.

ABO - American Board of Ophthalmology Practice Test

ABO - American Board of Ophthalmology Practice Test

ABO Neuro-Ophthalmology and Orbit 2