A 68-year-old woman notices drooping of both upper lids worsening towards the end of the day when reading. The upper lid crease is high and deep bilaterally, levator function is normal at 14 mm, and there is mild lagophthalmos on downgaze. The MOST likely diagnosis is:

• A Myogenic ptosis
• B Neurogenic ptosis
• C Aponeurotic (involutional) ptosis ✓
• D Mechanical ptosis

Explanation

Aponeurotic ptosis results from dehiscence or stretching of the levator aponeurosis from its tarsal insertion, classically in older patients. It preserves levator function because the muscle itself is intact, and produces a characteristically high, deep lid crease as the aponeurosis retracts. Mild lagophthalmos on downgaze occurs from poor lid excursion. Myogenic ptosis would show reduced levator function, which is absent here, ruling out that tempting alternative.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

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Written and medically reviewed by the StethoPrep medical team.