What is the likely diagnosis and appropriate treatment for a patient with foreign-body sensation, conjunctival redness, and tearing without an apparent ocular foreign body?

Foreign Body Sensation with Red, Watering Eye and No Visible Foreign Body

The most likely diagnosis is dry eye disease (DED), and you should initiate treatment with artificial tears, environmental modifications, and consider topical NSAIDs for symptom relief while ruling out corneal abrasion with fluorescein staining. 1

Differential Diagnosis Priority

The constellation of foreign body sensation, redness, and tearing without a visible foreign body most commonly indicates:

• Dry eye disease (most common) – Tear film instability is the most frequent presentation, more common than combined-mechanism or aqueous-deficient dry eye alone 1
• Corneal abrasion – May not be visible without fluorescein staining 2, 3
• Embedded foreign body – Can be missed on initial inspection, particularly under the upper eyelid 2
• Blepharitis or meibomian gland dysfunction – Often coexists with dry eye 1
• Allergic or viral conjunctivitis – Though typically presents with more discharge 4

Immediate Assessment Steps

Perform these specific examinations before initiating treatment:

• Visual acuity testing – Establishes baseline function and identifies vision-threatening conditions requiring urgent referral 2
• Fluorescein staining – Essential to identify corneal epithelial defects that may not be grossly visible; staining becomes more apparent after 2 minutes and is enhanced with yellow filter 1, 2
• Eyelid eversion – Check the tarsal conjunctiva for retained foreign bodies that cause persistent symptoms 2
• Pupil examination – An irregular pupil indicates penetrating injury requiring emergency ophthalmology referral 2

Red Flags Requiring Immediate Ophthalmology Referral

Do not delay referral if any of these are present:

• Moderate-to-severe pain not relieved by topical anesthetics 2, 4
• Vision loss or significant visual changes 2, 5
• Eye bleeding or irregular pupil 2
• High-velocity injury mechanism (grinding, metal work, nailing) 2, 3
• Visible corneal opacity, haze, ulceration, or purulent discharge 2
• Severe photophobia 2, 5

Treatment Algorithm for Dry Eye Disease (Most Likely Diagnosis)

When fluorescein staining is negative and no foreign body is found:

First-Line Management:

• Artificial tears – Use preservative-free formulations frequently throughout the day; symptoms typically worsen later in the day with prolonged visual tasks 1, 6
• Environmental modifications – Address exacerbating factors including wind, low humidity, air travel, and prolonged computer use with decreased blink rate 1, 6
• Topical NSAIDs – Ketorolac can significantly decrease foreign body sensation, pain, and photophobia even in dry eye 2, 3
• Eyelid hygiene – Address any concurrent blepharitis or meibomian gland dysfunction 1

Additional Considerations:

• Review medications – Antihistamines, diuretics, antidepressants, beta-blockers, and any anticholinergic drugs can worsen dry eye 1
• Assess systemic conditions – Sjögren syndrome, rheumatoid arthritis, rosacea, and other inflammatory diseases are associated with dry eye 1
• Contact lens use – If present, discontinue immediately and reassess 2

Treatment for Corneal Abrasion (If Fluorescein Positive)

If fluorescein staining reveals epithelial defect:

• Broad-spectrum topical antibiotic prophylaxis – Moxifloxacin four times daily or gatifloxacin to prevent infection 2, 3
• Topical NSAID – Ketorolac for pain, photophobia, and foreign body sensation 2, 3
• Cycloplegic agent – Cyclopentolate to reduce ciliary spasm pain 2, 3
• Oral analgesics – Acetaminophen or NSAIDs for additional pain relief 2, 3
• Avoid eye patching – Not recommended for corneal abrasions 3

Follow-Up Requirements

Mandatory follow-up timing depends on findings:

• If corneal abrasion or foreign body removed – Ophthalmology follow-up within 24-48 hours to monitor for infection development 2, 3
• If dry eye disease – Follow up in 2-4 weeks to assess treatment response; earlier if symptoms worsen 1

Warning Signs to Return Immediately

Instruct patients to seek urgent care if they develop:

• Worsening pain or vision 2, 7
• Increasing redness beyond initial presentation 2, 7
• New discharge or purulent material 2, 7
• Persistent foreign body sensation despite treatment 2, 7
• New photophobia 5

Common Pitfalls to Avoid

• Missing embedded foreign bodies – Always evert the upper eyelid; foreign bodies on the tarsal conjunctiva cause linear vertical corneal abrasions 2
• Assuming negative gross examination rules out pathology – Fluorescein staining is essential; corneal abrasions and subtle foreign bodies are frequently missed without it 1, 2
• Overlooking dry eye as a diagnosis – The foreign body sensation in dry eye can be identical to actual foreign body presence; tear film instability is extremely common 1, 6
• Rubbing the eye – This can embed foreign bodies deeper or cause corneal abrasion 7
• Using preserved artificial tears excessively – Preservatives can worsen ocular surface disease; use preservative-free formulations 1