What is the appropriate evaluation and management for a patient with protruding eyes (exophthalmos)?

Evaluation and Management of Protruding Eyes (Exophthalmos)

Measure exophthalmos immediately with an exophthalmometer and obtain urgent orbital imaging (MRI preferred, CT acceptable) to identify the underlying cause, as proptosis can signal vision-threatening conditions including thyroid eye disease, orbital tumors, or compressive optic neuropathy that require prompt intervention. 1, 2, 3

Initial Evaluation

Critical Measurements and Examination

• Exophthalmometry is mandatory to quantify the degree of proptosis (normal <21mm from orbital rim) and establish baseline measurements for monitoring disease progression 1, 3
• Assess for compressive optic neuropathy by checking visual acuity, color vision, visual fields, pupillary responses, and funduscopic examination for disc edema or optic atrophy 1, 2
• Evaluate extraocular muscle function including ductions, versions, and presence of restrictive strabismus, as 30-50% of thyroid eye disease patients develop restrictive myopathy affecting primarily the inferior rectus, then medial rectus 2
• Document eyelid retraction and corneal exposure since these increase evaporation and risk corneal decompensation 4

Diagnostic Imaging

• MRI of the orbits is the optimal imaging modality to evaluate extraocular muscle involvement, orbital fat volume, and degree of orbital apex crowding 1, 2
• CT imaging is acceptable and demonstrates tendon-sparing muscle enlargement, proptosis patterns (bilateral but often asymmetric), and helps determine if the superior oblique is involved 1
• Imaging is essential to differentiate thyroid eye disease from orbital tumors (cavernous hemangioma), vascular anomalies, inflammatory disorders, or infectious causes 3

Differential Diagnosis and Workup

Thyroid Eye Disease (Most Common)

• Thyroid function tests and immune studies should be ordered, though patients may be hyperthyroid, hypothyroid, or euthyroid at presentation 1
• The condition results from autoimmune inflammation where stimulatory autoantibodies target the thyroid-stimulating hormone receptor (TSHR), activating orbital fibroblasts and causing inflammatory edema that can progress to fibrosis 2
• Proptosis is typically axial and bilateral in 85-90% of cases, though displacement in vertical/horizontal axes occurs when intense muscle enlargement produces mass effect 5

Other Etiologies to Consider

• Orbital tumors (cavernous hemangioma being common), vascular anomalies, inflammatory disorders, and infectious causes all require imaging differentiation 3
• Pseudoproptosis can mimic true exophthalmos and must be distinguished through comprehensive evaluation 3

Immediate Management

Corneal Protection (Universal First Step)

• Ocular lubricants are almost always needed to combat exposure from eyelid retraction and proptosis 1
• Punctal plugs are useful for enhancing tear retention 1
• For acute presentations with corneal decompensation risk: use moisture chambers, swimming goggles, or temporary tarsorrhaphies/blepharorrhaphies while awaiting definitive treatment 4

Lifestyle Modification

• Counsel patients to cease smoking immediately, as smoking worsens thyroid eye disease outcomes 1

Medical Management for Thyroid Eye Disease

First-Line Therapy

• Teprotumumab (IGF-IR inhibitor) reduces proptosis and clinical activity scores in many patients with active thyroid eye disease 1
• Teprotumumab has been shown to improve subjective diplopia scores in both active and chronic disease and reduce the need for strabismus surgery 1
• Contraindications include: pregnancy (absolute), inflammatory bowel disease (relative), and caution with pre-existing hearing loss 1
• Common adverse effects: hyperglycemia, muscle spasms, nausea, alopecia, diarrhea, tinnitus, hearing impairment, dysgeusia, headache, weight loss, nail disorders, menstrual disorders 1

Alternative Medical Therapies

• Selenium supplementation reduces inflammatory symptoms in patients with selenium deficiency and milder thyroid eye disease, though it doesn't impact hyperthyroidism control in selenium-replete populations 1
• High-dose pulse steroid infusion is indicated for severe cases, particularly with compressive optic neuropathy 1
• In Europe, biologics such as Tocilizumab, Rituximab, or Fingolimod are used as alternatives 1

Surgical Management

Indications for Orbital Decompression

• Severe proptosis with compressive optic neuropathy requires urgent orbital decompression 1, 5
• Inactive disease with disfiguring exophthalmos that has not responded to medical management 5
• Ocular hypertension or corneal exposure refractory to conservative measures 5
• Consultation with an orbital disease specialist should be considered in patients with concurrent proptosis and significant strabismus, even without compressive optic neuropathy 1

Surgical Approach

• Decompression typically involves removal of orbital floor, lateral wall, and medial wall (ethmoidal part), combined with retrobulbar fat removal 6
• Preservation or improvement in visual acuity occurs in the vast majority of patients (all but one in a 28-patient series), though diplopia may not improve and can worsen 7
• Strabismus surgery should be deferred until the inflammatory phase has resolved and measurements are stable, as muscle involvement can change during active disease 1

Eyelid Surgery

• Eyelid retraction surgery (lengthening of anterior/posterior/mid-eyelid lamellae) is performed after orbital decompression and once inflammation has resolved 4
• Upper eyelid levator aponeurosis division may be performed during decompression to improve symmetry 6

Follow-Up and Monitoring

Surveillance Protocol

• Monitor exophthalmometry measurements at each visit to track disease progression or response to treatment 1
• Screen for optic neuropathy with visual acuity, color vision, visual fields, pupillary examination, and funduscopy at every visit 1, 2
• Optical coherence tomography and automated threshold visual fields provide ancillary information for screening and monitoring compressive optic neuropathy 1
• Binocular field testing to map the region of single binocular vision can be helpful for functional assessment 1

Common Pitfalls

• Do not delay imaging in patients with acute onset exophthalmos, as this may represent orbital tumors, infection, or rapidly progressive thyroid eye disease requiring urgent intervention 3, 4
• Do not perform strabismus surgery during active inflammatory phase, as muscle measurements will change and surgical outcomes will be suboptimal 1
• Do not assume euthyroid status excludes thyroid eye disease, as patients can present with any thyroid function status 1
• The majority of patients with minimal exophthalmos do not require special treatment and tend to improve spontaneously, but close monitoring is essential 5