What could be causing pain on the surface of my eye?

Ocular Surface Pain: Differential Diagnosis and Management

Your eye pain is most likely caused by dry eye disease, neuropathic ocular pain, or ocular surface inflammation—conditions where symptoms often far exceed visible signs on examination. 1

Key Diagnostic Approach

Immediate Assessment Priorities

The critical first step is determining whether you have nociceptive pain (from actual tissue damage) versus neuropathic pain (from nerve dysfunction), as this fundamentally changes treatment. 1

Red flags requiring emergency evaluation within 24 hours include: 1

• Moderate to severe pain (beyond irritation or foreign body sensation)
• Vision loss or blurring
• Severe light intolerance
• Unilateral redness (suggests infection or inflammation rather than dry eye)
• Visible corneal damage or purulent discharge

The Proparacaine Challenge Test

This simple office test distinguishes peripheral from central pain sources and should be performed when pain is present: 1

• If topical anesthetic (proparacaine 0.5%) provides complete relief: peripheral/nociceptive pain predominates
• If partial relief: mixed peripheral and central components
• If no relief: central neuropathic pain is likely

This distinction is crucial because peripheral pain responds to topical therapies while central pain requires systemic neuromodulators. 1

Most Likely Diagnoses

Neuropathic Ocular Pain (NOP)

NOP is characterized by symptoms grossly out of proportion to clinical signs—you may have severe burning, stinging, or aching pain with minimal findings on examination. 1

Common triggers include: 1

• Prior ocular surgery (LASIK, cataract surgery)
• Chronic dry eye or inflammation
• Previous eye infections
• Contact lens wear
• Idiopathic onset

Hallmark symptoms suggesting neuropathic pain: 1

• Burning or stinging quality
• Severe light sensitivity (photoallodynia)
• Wind sensitivity (hyperalgesia to air movement)
• Pain persisting despite treatment of surface abnormalities

Dry Eye Disease

Aqueous deficiency or evaporative dry eye causes surface pain through activation of corneal nociceptors. 1

Key examination findings to assess: 1

• Tear film break-up time (TBUT) with fluorescein
• Corneal and conjunctival staining patterns
• Schirmer's test or phenol red thread for tear volume
• Meibomian gland dysfunction assessment
• Tear osmolarity (though monitoring utility is controversial)

Treatment Algorithm

First-Line Topical Management

Start with preservative-free lubricants 2-4 times daily, escalating based on severity: 1

Mild symptoms:

• Preservative-free artificial tears 2-4 times daily 1

Moderate symptoms:

• Preservative-free lubricants 2-4 times daily PLUS
• Olopatadine twice daily (addresses allergic/inflammatory component) 1

Severe symptoms or inadequate response:

• Continue above PLUS
• Tacrolimus ointment to lid margins once daily 1
• Consider ophthalmology referral within 4 weeks 1

Adjunctive Ocular Surface Therapies

For peripheral neuropathic pain or refractory surface disease: 1

• Autologous serum tears: Nerve regenerative properties for peripheral neuropathic pain 1, 2
• Cryopreserved amniotic membrane (CAM): Anti-inflammatory and neurotrophic effects; 78.57% tolerance rate when placed in bandage contact lenses for patients with severe hyperalgesia 1
• Moisture chamber goggles: Reduce evaporative stress 1
• Treat meibomian gland dysfunction: Hot compresses, lid massage, oral doxycycline or azithromycin 1

Systemic Neuromodulator Therapy

If the proparacaine test shows no relief (central pain) or symptoms persist despite optimal topical therapy, oral neuromodulators are indicated: 1

Recommended agents (used alone or in combination): 1

• Pregabalin
• Gabapentin
• Duloxetine
• Amitriptyline or nortriptyline
• Low-dose naltrexone

Critical counseling point: These medications require 3-4 months at therapeutic dose to achieve pain reduction—set expectations early to ensure adherence. 1

Specialized Interventions

For patients with light sensitivity and headache: 1, 2

• Transcutaneous electrical nerve stimulation devices
• Periorbital botulinum toxin A injections

For cutaneous allodynia or post-surgical pain: 1

• Periocular nerve blocks (corticosteroid plus long-acting sodium channel blocker)

For severe hyperalgesia with environmental triggers: 1

• Scleral lenses (PROSE) or therapeutic soft bandage contact lenses provide immediate symptom relief by shielding corneal nociceptors, though infection risk limits long-term use

Common Pitfalls to Avoid

Do not dismiss pain when examination appears normal—this is the hallmark of neuropathic ocular pain and requires different treatment than standard dry eye. 1

Do not continue escalating topical therapies indefinitely without considering systemic neuromodulators if symptoms persist beyond 3 months of appropriate topical management. 1

Address psychiatric comorbidities—anxiety, depression, and mood disorders commonly accompany neuropathic ocular pain due to neural connections between corneal nerves and emotional processing centers. 1

Rule out other ocular surface comorbidities that can trigger or perpetuate pain: blepharitis (including demodex), ocular allergies, conjunctivochalasis, and exposure keratopathy. 1