Quiz: A Stare With a Catch

Test your understanding of this case with 11 questions.

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Case Information

Review the case details while answering questions

PATIENT DEMOGRAPHICS

71-year-old female

PRESENTING COMPLAINT

Presented with a several-month history of a "staring" appearance to both eyes, noticed by the patient and her family, along with mild ocular grittiness.

EXAMINATION FINDINGS

Visual Acuity: OD: 6/6. OS: 6/6

Pupils: Equal and reactive, no RAPD

Fundus: No evidence of compressive optic neuropathy at this time (normal VA, no RAPD, no colour vision deficit)

INVESTIGATIONS

Primary gaze demonstrating bilateral upper lid retraction

Attempted upgaze with a fixation target demonstrating absent elevation and persistent lid retraction

Downgaze demonstrating the upper lids catching up with the limbus as retraction resolves

Clinical Photography: Demonstrates bilateral upper lid retraction in primary gaze, resolution of retraction on downgaze as the lids follow the globe, and absent upgaze on formal testing with a fixation target.

Question 1 of 11

Bilateral upper lid retraction, as seen in this patient, has several possible causes. Which is the most common cause in an older adult?

Bilateral myasthenic ptosis with compensatory lid retraction

Collier's sign, from a dorsal midbrain lesion

Thyroid eye disease, the most common cause overall

Bilateral Horner's syndrome, affecting both eyes

Question 2 of 11

There is no upgaze on formal testing. What does this finding suggest?

A restrictive process limiting elevation, not a neurogenic palsy

Voluntary limitation of gaze, unrelated to organic pathology

A supranuclear vertical gaze palsy, as in dorsal midbrain syndrome

A bilateral CN III palsy affecting the superior rectus

Question 3 of 11

What is the proposed mechanism for this patient's upper lid retraction, given the restricted upgaze?

A separate, coincidental bilateral CN VII palsy affecting eyelid closure

Sympathetic overactivity of Müller's muscle, unrelated to any restriction

Direct fibrotic shortening of the levator muscle itself, unrelated to the inferior rectus

Restricted elevation from a tight inferior rectus, with effort shared via Hering's Law

Question 4 of 11

What does Hering's Law of equal innervation state?

Each extraocular muscle is innervated entirely independently of others

Only the eye with better vision receives innervational signals

Yoked muscles receive equal, simultaneous innervation for a given movement

Innervation to eye muscles is inversely proportional between the eyes

Question 5 of 11

On downgaze, the upper lids "catch up" with the limbus and the retraction becomes less apparent. Why does this occur?

Downgaze isn't restricted, so less effort and co-contraction occur

This finding indicates the diagnosis is not thyroid eye disease

The inferior rectus fully relaxes and lengthens normally on downgaze

The lid retraction is entirely unrelated to eye position in any direction

Question 6 of 11

What findings, if present, would raise concern for compressive optic neuropathy in this patient?

Bilateral upper lid retraction alone, as already present

A "staring" appearance noticed by the patient's family

Restricted upgaze alone, as already demonstrated

Reduced visual acuity, impaired colour vision, or a new RAPD

Question 7 of 11

What initial investigations are most appropriate to confirm the suspected underlying diagnosis?

Genetic testing for an underlying hereditary myopathy

Tensilon (edrophonium) testing for myasthenia gravis

Lumbar puncture, testing for oligoclonal bands

Thyroid function tests and TSH-receptor antibody testing

Question 8 of 11

This patient is a current smoker. What is the significance of this in the context of her diagnosis?

Smoking has no established relationship with this condition

Smoking is protective against progression of this condition

Smoking is the most significant modifiable risk factor for severity

Smoking is relevant only to the thyroid dysfunction itself

Question 9 of 11

What is the most likely diagnosis?

Bilateral Horner's syndrome with compensatory lid changes

Bilateral dorsal midbrain syndrome from an intracranial mass

Myasthenia gravis affecting bilateral lid and motility function

Thyroid eye disease, with restrictive inferior rectus myopathy

Question 10 of 11

What are the general principles of managing this patient's condition?

Immediate orbital decompression surgery in all cases regardless

Reassurance only, since this condition never needs management

Ophthalmology management alone, without any endocrine input

Multidisciplinary care, smoking cessation, and optic nerve monitoring

Question 11 of 11

Classic teaching attributes thyroid eye disease lid retraction to sympathetic overactivity of Müller's muscle. How does this case add to that understanding?

It indicates this presentation cannot be thyroid eye disease

It demonstrates a second, restrictive mechanism via Hering's Law

It disproves the sympathetic overactivity mechanism entirely

It shows lid retraction here has only one possible mechanism