A 70-year-old man presents with a unilateral lower lid that turns inward, causing chronic tearing and corneal irritation. Examination shows that the lid margin inverts on sustained downgaze but returns to normal position with manual lid eversion. The most likely diagnosis and mechanism is:
- A Cicatricial entropion due to conjunctival scarring
- B Involutional entropion due to lower lid retractor disinsertion and pre-tarsal orbicularis over-riding ✓
- C Spastic entropion due to orbicularis over-riding
- D Mechanical entropion from mass effect
Correct answer: B. Involutional entropion due to lower lid retractor disinsertion and pre-tarsal orbicularis over-riding
Explanation
Involutional (senile) entropion results from multiple age-related changes: horizontal lid laxity, disinsertion/attenuation of lower lid retractors, and pre-tarsal orbicularis override by pre-septal orbicularis. The lid inverts on downgaze (when orbicularis contracts) but can be temporarily everted. Cicatricial entropion is due to conjunctival/tarsal scarring (trachoma, SJS), with foreshortening of the posterior lamella. Spastic entropion follows blepharospasm or ocular irritation in the acute setting.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.