What is the differential diagnosis and initial management for a patient presenting with eye pain?

Differential Diagnosis for Eye Pain

Eye pain requires immediate systematic evaluation to distinguish vision-threatening emergencies from benign conditions, with the key differentiating factors being presence of vision changes, photophobia, and associated systemic symptoms. 1, 2

Immediate Vision-Threatening Emergencies

These conditions require urgent ophthalmology referral within hours to prevent permanent vision loss:

Acute Angle-Closure Glaucoma

• Bilateral transient episodes with halos around lights, opaque vision, and eye pain are pathognomonic for intermittent angle closure 3
• Halos result from pressure-induced corneal edema when intraocular pressure rises 3
• Untreated fellow eyes have 50% risk of acute crisis within 5 years, with 18% becoming blind 3
• Mid-dilated, poorly reactive, or oval pupil on examination 2
• Requires gonioscopy to confirm iridotrabecular contact and laser peripheral iridotomy as definitive treatment 3

Infectious Keratitis

• Presents with severe pain, photophobia, and blurred vision 2, 4
• Requires fluorescein staining to evaluate corneal epithelial integrity 1
• Demands immediate ophthalmologic consultation before any treatment initiation 2

Anterior Uveitis/Iritis

• Severe pain, photophobia, and blurred vision 2, 4
• May show relative afferent pupillary defect if optic nerve involved 2
• Requires slit-lamp biomicroscopy and urgent specialist assessment 2

Scleritis

• Deep, boring eye pain that may radiate to face and jaw 4, 5
• Often associated with systemic autoimmune conditions 4
• Requires immediate ophthalmology consultation 4

Orbital Cellulitis

• Periorbital soft tissue swelling, pain, restricted eye movement 6, 4
• Vision-threatening emergency requiring immediate imaging and treatment 6

Optic Neuritis

• Pain with eye movement, vision loss, relative afferent pupillary defect 2, 4
• Requires urgent ophthalmology referral 4, 5

Non-Emergent but Significant Conditions

Dry Eye Syndrome

• Burning, stinging pain often disproportionate to clinical signs 1, 7
• Managed with ocular lubricants and anti-inflammatory treatment 1
• Patients with severe pain less responsive to standard dry eye treatments 7

Neuropathic Corneal Pain

• Symptoms outweigh clinical signs—commonly misdiagnosed 1
• Associated with prior ocular surgery, chronic surface abnormalities, or systemic conditions (migraine, fibromyalgia) 1, 7
• Anesthetic challenge test helps differentiate from other causes 1
• Requires topical nerve regenerative therapies for peripheral pain or oral neuromodulators for central pain 1
• Combination therapy addressing multiple factors is essential 6

Recurrent Corneal Erosion

• Sharp pain upon awakening, history of prior corneal trauma 8
• Fluorescein staining reveals epithelial defects 8

Intermittent Angle Closure (Non-Acute)

• Transient episodes that self-resolve before permanent damage 3
• Risk factors: female, Asian/Inuit ethnicity, age >50, hyperopia, shallow anterior chamber 3
• Do not dilate pupils until after iridotomy performed 3

Corneal Abrasion

• Foreign body sensation, tearing, photophobia 4, 5
• Fluorescein staining confirms diagnosis 4

Benign Conditions

Conjunctivitis

• Redness, discharge, foreign body sensation without vision changes 4
• Most common cause of eye pain in primary care 4

Hordeolum (Stye)

• Localized lid pain and swelling 4
• No vision changes 4

Critical Examination Components Required

Every patient with eye pain requires:

• Visual acuity testing as essential baseline 2
• Pupil examination for reactivity and afferent defects 2
• Slit-lamp biomicroscopy of anterior segment 2
• Intraocular pressure measurement 2, 3
• Fluorescein staining for corneal integrity 1, 2
• Gonioscopy if angle closure suspected 3

Key Clinical Decision Points

Immediate ophthalmology referral if ANY of the following:

• Vision changes (blurred vision, halos, vision loss) 2, 3
• Severe photophobia 2
• Mid-dilated or poorly reactive pupil 2, 3
• Corneal opacity or infiltrate 2
• Elevated intraocular pressure 3

Imaging considerations:

• Non-contrast thin-section orbital CT with multiplanar reconstructions for suspected traumatic injury 6
• MRI contraindicated if metallic foreign body suspected 6

Common Pitfalls to Avoid

• Never dismiss transient symptoms as benign—these represent warning episodes before potentially blinding acute attacks 3
• Do not delay fellow eye prophylaxis after treating one eye for angle closure 3
• Avoid fluorescein-anesthetic combination drops for tear break-up time assessment 1
• Do not initiate treatment before establishing diagnosis in patients with blurred vision, pain, and photophobia 2
• Neuropathic pain is frequently misdiagnosed because clinical signs are minimal despite severe symptoms 1