What is the differential diagnosis for a patient presenting with blurry vision and a sensation of foreign body in the eye?

Differential Diagnosis for Blurry Vision with Foreign Body Sensation

The combination of blurry vision and a sandy/gritty foreign body sensation most commonly indicates corneal surface pathology, with the differential including corneal abrasion/foreign body, dry eye disease, corneal edema, infectious keratitis, and acute angle-closure crisis.

Primary Differential Considerations

Corneal Abrasion or Foreign Body

• This is the most urgent diagnosis to rule out, particularly if symptoms are acute in onset 1, 2
• Look for history of trauma, contact lens wear, or high-velocity injury (grinding, nailing) 1, 2
• Foreign body sensation with blurred vision is the classic presentation 3
• May present with pain, photophobia, redness, and tearing 3
• High-velocity injuries require immediate ophthalmology referral due to risk of penetrating injury 1, 2

Dry Eye Disease (DED)

• Extremely common, affecting 5-30% of the population, up to 75% in elderly 4
• Characteristic gritty, sandy foreign body sensation with visual disturbances 5, 4
• Blurred vision occurs from tear film instability causing fluctuating vision with blinking 6
• Symptoms often worse than objective signs on examination 5
• More common in women, particularly postmenopausal (9.8% prevalence) 4

Corneal Edema

• Presents with blurred vision (often worse upon waking, improving later in day) and intermittent foreign body sensation 3
• Diurnal pattern is key: symptoms worse in morning, clearer later as evaporation reduces edema 3
• May indicate underlying endothelial dysfunction, elevated IOP, or inflammation 3
• Can be acute (from elevated IOP, inflammation, corneal hydrops) or gradual (Fuchs dystrophy, endothelial dysfunction) 3

Infectious Keratitis

• Bacterial, fungal, parasitic, or viral infection of the cornea 3
• Frequently presents acutely with pain, blurred vision, foreign body sensation, photophobia, and redness 3
• Contact lens wear is a major risk factor requiring immediate attention 2
• Requires urgent treatment to prevent vision loss 3

Acute Angle-Closure Crisis (AACC)

• Presents with sudden onset of eye pain, blurred vision, halos around lights, headache, nausea, and redness 3
• Corneal edema from very high IOP causes the blurred vision 3
• This is a true emergency requiring immediate IOP reduction to prevent permanent vision loss 3
• More common in hyperopic/short eyes, older phakic patients 3
• May have mid-dilated, poorly reactive pupil 3

Secondary Considerations

Uveitis/Episcleritis

• Uveitis presents with eye pain, blurred vision, photophobia, and may have foreign body sensation 3
• Can be bilateral, insidious onset, and long-lasting 3
• Episcleritis may present with hyperemic sclera, itching, and burning sensation 3

Interstitial Keratitis

• Nonsterile or sterile inflammation causing corneal opacification 3
• Presents with blurred vision and foreign body sensation 3

Critical Clinical Approach

Immediate Red Flags Requiring Urgent Referral

• High-velocity injury history (grinding, nailing) 1, 2
• Penetrating injury or suspicion of intraocular foreign body 1, 2
• Irregular pupil, eye bleeding, or vision loss after trauma 2
• Severe pain with nausea (suggests AACC) 3
• Contact lens-related symptoms 2

Key History Elements

• Onset timing: Acute (hours) suggests foreign body, infection, or AACC; gradual (days-weeks) suggests dry eye or corneal edema 3
• Diurnal pattern: Worse in morning suggests corneal edema from endothelial dysfunction 3
• Trauma history: Even minor trauma can cause abrasion 1, 2
• Contact lens use: Increases risk of infection and abrasion 2
• Medications: Anticholinergics, topiramate, sulfonamides can cause angle closure 3

Essential Physical Examination Findings

• Corneal examination: Look for epithelial defects (abrasion), edema (microcystic or stromal), infiltrates (infection), or foreign body 3
• Pupil assessment: Mid-dilated/poorly reactive suggests AACC; relative afferent pupillary defect suggests optic nerve involvement 3
• IOP measurement: Elevated IOP indicates angle closure or glaucoma 3
• Anterior chamber depth: Shallow chamber suggests angle-closure risk 3
• Conjunctival injection pattern: Ciliary flush suggests more serious pathology 3

Common Pitfalls to Avoid

• Do not rub the eye as this can embed foreign bodies deeper or worsen corneal abrasion 2
• Do not dismiss symptoms in patients where signs seem minimal—dry eye symptoms often exceed objective findings 5
• Do not patch corneal abrasions 1
• Consider mental health disorders (depression, anxiety) as contributing factors when symptoms far exceed signs in dry eye 5