14/10/2025
🧠 Orbital Fat Prolapse
🔹 Definition
Orbital fat prolapse refers to herniation of intraconal orbital fat through a weakened Tenon’s capsule, usually seen as a soft, yellowish subconjunctival mass in the superotemporal quadrant.
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🔹 Etiology / Causes
1. Idiopathic (spontaneous) — common in elderly due to orbital septal laxity.
2. Secondary causes:
3. Trauma (blow-out fracture or surgical weakening)
4. Post-surgery (after enucleation, orbital surgery)
5. Raised intraorbital pressure
6. Chronic steroid use (causes fat atrophy and redistribution)
7. Connective tissue disorders
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🔹 Pathophysiology
Weakness or dehiscence of Tenon’s capsule and intermuscular septa allows orbital fat (usually intraconal) to herniate anteriorly into the subconjunctival space.
Common site: superotemporal quadrant, between the lateral re**us and levator muscle.
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🔹 Clinical Features
1. Soft, yellowish, mobile subconjunctival mass in superotemporal quadrant
2. Painless and reducible with gentle pressure
3. Increases on globe retropulsion or Valsalva maneuver
4. Covered by intact, normal conjunctiva
5. Often bilateral and symmetric in elderly
6. No inflammation or restriction of ocular movements
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🔹 Differential Diagnosis
Condition - Key Differentiating Feature
1. Dermolipoma Congenital, non-reducible, immobile, adherent to conjunctiva
2. Lacrimal gland prolapse Firm, pinkish, non-reducible, located superolaterally
3. Orbital mass / lipoma May be firm or fixed, progressive enlargement
4. Conjunctival cyst Translucent, fluid-filled appearance
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🔹 Investigations
Clinical diagnosis in most cases
CT / MRI orbit: shows anterior herniation of orbital fat through Tenon’s capsule without a discrete mass.
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🔹 Management
1. Observation — if asymptomatic (most cases)
2. Surgical excision — indicated if:
Cosmetic concern
Recurrent exposure or irritation
Diagnostic uncertainty
Technique: Conjunctival incision → excision of herniated fat → closure of Tenon’s capsule.
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🔹 Prognosis
Benign condition
Excellent prognosis after surgical repair
Recurrence rare if Tenon’s capsule properly closed.
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🧾 Key Points for Exams
Common in elderly males
Superotemporal, soft, yellow, reducible mass
Differential: dermolipoma (non-reducible)
Confirm with imaging if atypical
Treatment: conservative or surgical excision.
