Bulging eyes (exophthalmos)

Bulging Eyes (Exophthalmos / Proptosis)

Introduction

Exophthalmos (or proptosis) refers to abnormal protrusion of the eyeball beyond the orbital rim. It may be unilateral (one eye) or bilateral (both eyes), acute or chronic, and is often first noticed by the patient or relatives as a change in appearance.

The most common cause in adults is thyroid eye disease (Graves’ orbitopathy), while in children, orbital tumors or infections are more likely. Because it can threaten vision, eye movement, and cosmetic function, early recognition and treatment are essential.

---

Pathophysiology

• Exophthalmos occurs due to increased orbital contents (inflammation, fat expansion, muscle swelling, tumor, infection, or hemorrhage).

• In thyroid eye disease, autoantibodies stimulate fibroblasts → deposition of glycosaminoglycans → orbital fat and muscle swelling → eye protrusion.

• Prolonged proptosis can cause exposure keratopathy, corneal ulceration, optic nerve compression, and vision loss.

---

Causes of Exophthalmos

1. Endocrine / Autoimmune

• Graves’ disease (thyroid-associated orbitopathy): Most common. Bilateral, associated with hyperthyroidism.

• Hashimoto’s thyroiditis (rarely).

2. Inflammatory / Infective

• Orbital cellulitis: Acute, painful proptosis with fever, emergency.

• Idiopathic orbital inflammatory disease (orbital pseudotumor).

• Sarcoidosis, granulomatosis with polyangiitis.

3. Neoplastic

• Orbital tumors: Lymphoma, rhabdomyosarcoma (children), optic nerve glioma, meningioma.

• Metastatic tumors (breast, lung, prostate).

• Vascular malformations (hemangioma, carotid–cavernous fistula).

4. Vascular / Traumatic

• Retrobulbar hemorrhage (after trauma or surgery).

• Carotid–cavernous fistula (pulsatile exophthalmos, bruit).

5. Miscellaneous

• Congenital craniofacial abnormalities (Crouzon syndrome).

• Allergic orbital swelling.

---

Clinical Features

• Eye appearance: Protruding eye(s), eyelid retraction.

• Ocular symptoms:

  • Grittiness, dryness.

  • Excess tearing.

  • Double vision (diplopia).

  • Eye pain or pressure.

• Vision symptoms:

  • Blurred vision.

  • Visual field defects.

  • Reduced color vision (suggests optic nerve compression).

• Systemic features:

  • Thyroid disease (weight loss, tremor, heat intolerance).

  • Fever and swelling (infection).

---

Diagnostic Approach

1. History

• Onset: acute (infection, hemorrhage) vs gradual (tumor, thyroid).

• Thyroid symptoms: hyperthyroidism, hypothyroidism.

• Trauma, surgery, infection history.

• Associated systemic disease (sarcoidosis, cancer).

2. Examination

• Measure degree of proptosis: Hertel exophthalmometry (>18 mm abnormal).

• Look for:

  • Eyelid retraction, lag.

  • Conjunctival injection, chemosis.

  • Extraocular muscle restriction.

  • Corneal exposure.

  • Fundoscopy: papilledema, optic atrophy.

3. Investigations

• Blood tests: Thyroid function tests (TSH, T4, T3), thyroid antibodies.

• Imaging:

  • CT orbit: muscle enlargement (thyroid eye disease), tumors, fractures.

  • MRI: soft tissue and optic nerve involvement.

• Biopsy: If tumor suspected.

• Cultures: If orbital cellulitis.

---

Management and Treatment

Treatment depends on the underlying cause, severity, and whether vision is threatened.

---

A. General Supportive Measures

• Lubricating eye drops (artificial tears).

• Protective sunglasses.

• Sleeping with head elevated.

• Smoking cessation (worsens thyroid eye disease).

---

B. Specific Medical Therapy

1. Thyroid Eye Disease (Graves’ Orbitopathy)

• Treat underlying thyroid disease:

  • Antithyroid drugs: Carbimazole 20–40 mg orally daily or Propylthiouracil 100–150 mg orally every 8 h.

  • Radioiodine therapy (with caution—may worsen eye disease).

  • Thyroidectomy if uncontrolled.

• Immunosuppression for active disease:

  • Prednisone 0.5–1 mg/kg orally daily, taper over weeks.

  • IV methylprednisolone (500–1000 mg weekly for 6–12 weeks) for severe cases.

  • Immunomodulators: Rituximab, Mycophenolate mofetil (used in refractory cases).

• Selenium supplements (100 mcg orally twice daily) shown to improve mild orbitopathy.

2. Orbital Cellulitis (Emergency)

• Hospital admission + IV antibiotics:

  • Ceftriaxone 2 g IV daily + Metronidazole 500 mg IV every 8 h.

  • Surgical drainage if abscess present.

3. Idiopathic Orbital Inflammation

• Prednisone 1 mg/kg/day orally → taper slowly.

4. Tumors

• Surgical excision if localized.

• Radiotherapy/chemotherapy depending on type.

5. Vascular Causes

• Retrobulbar hemorrhage: urgent lateral canthotomy to relieve pressure.

• Carotid–cavernous fistula: endovascular closure.

---

C. Surgical Treatment (for severe or vision-threatening cases)

• Orbital decompression surgery: To create space for swollen muscles/fat.

• Strabismus surgery: For persistent diplopia.

• Eyelid surgery: For exposure keratopathy or cosmetic improvement.

---

Complications

• Corneal exposure → keratitis, ulceration.

• Optic neuropathy → permanent vision loss.

• Cosmetic disfigurement, psychosocial impact.

• Recurrence (especially in thyroid eye disease).

---

Prognosis

• Thyroid eye disease: Active phase lasts 6–24 months; most stabilize but some need surgery.

• Orbital cellulitis: Good prognosis with early antibiotics; delayed treatment → blindness, intracranial spread.

• Tumors: Prognosis depends on type and stage.

• Vascular causes: Good if promptly treated.

---

Patient Education

• Seek urgent care for sudden eye bulging, pain, fever, or loss of vision.

• For thyroid-related cases, control thyroid function and quit smoking.

• Use artificial tears to protect cornea.

• Attend regular ophthalmology and endocrinology follow-up.

• Surgery may be needed for severe cases but is usually effective.