Eye Disorders Diagnosis

Transient Proptosis

• Induced by increasing cephalic venous pressure (e.g., Valsalva manoeuvre), a sign of orbital varices
• Speed of onset of proptosis may indicate aetiology:
  • Slow onset suggests benign tumour
  • Rapid onset seen in inflammatory disorders, malignant tumours, and caroticocavernous fistula

Enophthalmos

• Backward displacement of the globe
• Feature of orbital 'blowout fracture' (blunt injury to globe and orbit, fracturing thin orbital wall, and displacing orbital contents into an adjacent sinus)
• Also seen in Horner's syndrome, but this is a pseudo-enophthalmos due to narrowing of the palpebral fissure

Pain

• Present in inflammatory conditions, infective disorders, and rapidly progressing tumours
• Not usually present with benign tumours

Eyelid and Conjunctival Changes

• Conjunctival injection and swelling suggest inflammatory or infective process
• Infection associated with reduced eye movements, erythema, and swelling of the lids (orbital cellulitis)
• Anterior lid inflammation (preseptal cellulitis) has full eye movements and no globe inflammation, excluding orbital cellulitis
• Florid engorgement of conjunctival vessels suggests caroticocavernous fistula

Binocular Diplopia

• Occurs when only one eye is fixed on a target
• Causes:
  • Direct involvement of muscles in myositis and dysthyroid eye disease (Graves' disease)
  • Involvement of nerve supply to extraocular muscles (paralytic squint)

Visual Acuity

• Reduced by:
  • Exposure keratopathy from severe proptosis
  • Optic nerve involvement by compression or inflammation
  • Distortion of the macula due to compression of the globe by a posterior space-occupying lesion

Investigation of Orbital Disease

• CT and MRI scans help diagnose orbital disease by localizing the site of the lesion and demonstrating enlarged intraocular muscles
• Additional systemic tests depend on the differential diagnosis

Differential Diagnosis of Orbital Disease

• Traumatic orbital disease discussed in Chapter 16
• Disorders of extraocular muscles:
  • Dysthyroid eye disease and ocular myositis present with symptoms and signs of orbital disease
  • In children, rapidly developing proptosis may be caused by rhabdomyosarcoma of the extraocular muscles
• Infective disorders:
  • Orbital cellulitis is a serious condition that can cause blindness and may spread to cause a brain abscess