LID ANATOMY
This muscle closes the eyelids. Name its cranial nerve supply.
Orbicularis oculi
Facial nerve (CN VII)
This measurement runs from the corneal light reflex to the upper lid margin in primary gaze. Give its usual normal range.
MRD1
Approximately 4–5 mm
An older patient has gradual ptosis, a high lid crease, and 15 mm levator function. What is the most likely type?
Aponeurotic ptosis
The lower eyelid margin rotates inward and the lashes rub against the cornea. Name the malposition.
Entropion
The upper lid sits abnormally high and exposes sclera above the limbus in primary gaze. Name the malposition.
Upper eyelid retraction
This smooth muscle adds about 1–2 mm of upper lid elevation and receives sympathetic innervation.
Müller’s muscle
MRD1 is 2 mm and MRD2 is 5 mm. What is the palpebral fissure height?
7 mm
Ptosis varies during the day. Prolonged upgaze worsens it, the pupils are normal, and cooling improves it. What diagnosis fits?
Myasthenia gravis
After a cheek burn, the lower lid everts. Which lamella has typically shortened, and what type of ectropion results?
Anterior lamella
Cicatricial ectropion
At the first TED visit: pain on eye movement, eyelid redness, conjunctival redness, and chemosis. All other CAS items are absent. Calculate CAS and classify activity.
CAS = 4/7
Active TED
In the two-lamella surgical model, name the components of the anterior and posterior lamellae.
Anterior: skin and orbicularis
Posterior: tarsus and conjunctiva
To measure levator function accurately, which compensating muscle must you immobilize, and how?
Frontalis
Hold the brow firmly
A patient has aponeurotic ptosis and good levator function. Which external operation directly repairs the underlying attachment?
Levator aponeurosis advancement (Advance or reattach the aponeurosis to the tarsus)
The lower lid distracts easily from the globe and returns only after a blink. What defect is present, and which common operation addresses it?
Horizontal lid laxity
Lateral tarsal strip
Acute painful ptosis, a dilated pupil, and a “down-and-out” eye. Name the nerve palsy and the vascular cause to exclude urgently.
Third nerve palsy
Posterior communicating artery aneurysm
Attachments from this structure to the skin help form the upper eyelid crease.
Levator aponeurosis
The upper lid margin sits 1 mm below the corneal light reflex. What MRD1 should you record?
−1 mm
A child has severe congenital ptosis and levator function of 3 mm. Which operation commonly recruits the brow to lift the lid?
Frontalis sling
Name the three classic anatomic contributors to involutional lower lid entropion.
Horizontal laxity
Lower lid retractor disinsertion
Preseptal orbicularis override
TED with reduced colour vision, a new field defect, and an afferent pupillary defect. Can a low CAS rule out a sight-threatening complication? Name it.
No
Dysthyroid optic neuropathy
In cicatricial lid malposition, shortening of which lamella causes ectropion, and shortening of which causes entropion?
Ectropion: anterior lamella. Entropion: posterior lamella
When you manually elevate a ptotic upper lid, the opposite upper lid drops. Name this phenomenon and explain its importance before surgery.
Hering’s law of equal innervation. Elevating one lid reduces the shared drive to both levators, revealing contralateral ptosis. Unilateral repair may therefore produce asymmetry, and bilateral repair may be needed.
A patient has mild ptosis, good levator function, and satisfactory lid elevation after phenylephrine. Which posterior approach is commonly considered?
Müller muscle–conjunctival resection (MMCR). The phenylephrine response helps predict the potential lift. webeye.ophth.uiowa.edu
An older patient has involutional ectropion with horizontal laxity and an everted lower punctum. Tightening the lateral lid does not restore punctal position. Which additional procedure commonly addresses this?
Medial spindle, often combined with a lateral tarsal strip, to rotate the punctum back toward the globe.
A patient with TED develops reduced vision and colour perception. CT shows apical crowding. The optic discs look normal and CAS is 1/7.
Name the sight-threatening diagnosis and the first treatment class usually used urgently.
Dysthyroid optic neuropathy
Urgent high-dose IV glucocorticoids