What is the differential diagnosis for a patient who woke up with increasing pressure in one eye, accompanied by excessive tearing and redness?

Differential Diagnosis for Acute Unilateral Eye Pain with Pressure, Tearing, and Redness

This presentation is acute angle-closure glaucoma until proven otherwise, and requires immediate ophthalmology evaluation and intraocular pressure measurement within hours to prevent permanent blindness. 1, 2

Life/Sight-Threatening Diagnoses (Require Immediate Action)

Acute Angle-Closure Glaucoma (Primary Concern)

The combination of waking with increasing eye pressure sensation, excessive tearing, and redness is pathognomonic for acute angle-closure crisis, which can cause irreversible blindness within hours if untreated. 1, 2

Key distinguishing features to assess immediately:

• Mid-dilated, fixed pupil (not reactive to light) 1, 2
• Corneal edema (appears hazy/cloudy on examination) 1, 2
• Markedly elevated IOP >40 mmHg (globe feels rock-hard on palpation) 1, 3
• Blurred vision with halos around lights (from corneal edema) 1, 2
• Associated nausea/vomiting and headache (often mistaken for migraine or gastrointestinal illness) 2, 3

Critical action: Even non-ophthalmologists can diagnose markedly elevated IOP by gentle palpation of the globe through the closed eyelid—the eye will feel rock-hard compared to the normal fellow eye. 3

Intermittent Angle-Closure (Warning Episodes)

If symptoms are transient and self-resolving, this represents intermittent pupillary block with 50% risk of acute crisis within 5 years if untreated. 1, 4 The bilateral nature of primary angle-closure disease means both eyes are at risk even if only one is currently symptomatic. 4

Other Important Diagnoses to Consider

Corneal Pathology

Corneal abrasion or ulcer presents with sharp pain, foreign body sensation, photophobia, and visible epithelial defect on fluorescein staining, but typically has normal IOP and a reactive pupil—key differentiators from angle-closure. 1, 5

Corneal edema from endothelial dysfunction (Fuchs dystrophy) characteristically causes blurred vision worse upon waking that improves later in the day due to evaporation, but develops gradually over months rather than acutely overnight. 5

Anterior Uveitis

Presents with dull aching pain, photophobia, and circumlimbal injection, but has a small (miotic) pupil and normal or LOW IOP—opposite findings from angle-closure glaucoma. 1 Slit-lamp examination reveals cells and flare in the anterior chamber. 1

Scleritis/Episcleritis

Scleritis causes deep boring pain worse at night with violaceous hue and may radiate to the face, while episcleritis presents with milder discomfort and sectoral redness. 1 Both have normal pupils and IOP. 1

Retinal Artery Occlusion

Typically presents with sudden painless vision loss, but eye pain can occur with associated ischemia and requires immediate stroke center referral due to high concurrent cerebral infarction risk. 5, 1

Critical Decision Algorithm

Step 1: Immediate Assessment (Within Minutes)

• Measure IOP (tonometry or palpation if tonometer unavailable) 1, 2
• Assess pupil size and reactivity (mid-dilated and fixed = angle-closure) 1, 2
• Examine cornea (edema/haziness = angle-closure; epithelial defect = abrasion) 1, 2
• Check for vision loss (sudden loss = possible retinal artery occlusion requiring stroke workup) 5, 1

Step 2: If Acute Angle-Closure Suspected (High IOP + Mid-Dilated Pupil + Corneal Edema)

Initiate immediate medical therapy WITHOUT waiting for ophthalmology consultation—18% of untreated eyes become blind within 4-10 years: 1, 2

1. Topical beta-blocker (timolol 0.5%) 2, 6
2. Topical alpha-2 agonist (apraclonidine or brimonidine) 2, 6
3. Topical carbonic anhydrase inhibitor (dorzolamide) 2, 6
4. Oral or IV carbonic anhydrase inhibitor (acetazolamide 500mg) 2, 6
5. Oral or IV hyperosmotic agent (mannitol) 2, 6
6. Emergent ophthalmology consultation for laser peripheral iridotomy (LPI) once IOP controlled 1, 2

Step 3: If Normal IOP with Corneal Defect

Treat as corneal abrasion/ulcer: topical antibiotics, cycloplegic for comfort, pressure patch consideration, and ophthalmology follow-up within 24 hours. 1

Step 4: If Sudden Vision Loss Present

Immediate referral to certified stroke center regardless of pain presence—retinal artery occlusion has high concurrent cerebral infarction risk requiring stroke protocol workup within 72 hours. 5

Critical Pitfalls to Avoid

Never dilate the pupil in patients with suspected narrow angles or intermittent symptoms until after LPI is performed—dilation can precipitate acute crisis. 1, 4

Do not dismiss transient symptoms as benign—intermittent episodes are warning signs before potentially blinding acute attacks, with 50% progressing to acute crisis within 5 years. 1, 4

Do not delay treatment waiting for ophthalmology if acute angle-closure is suspected—initiate medical therapy immediately as permanent damage occurs within hours. 1, 2

Recognize that nausea/vomiting and headache may lead to misdiagnosis as migraine or gastrointestinal illness, delaying appropriate ophthalmic evaluation. 2, 3

Always treat the fellow eye prophylactically after acute angle-closure in one eye—bilateral LPI is required as acute attacks can occur within days in the untreated eye. 4, 2

Review all medications for precipitating drugs including adrenergics (decongestants, bronchodilators), anticholinergics (antidepressants, antihistamines), and sulfa-based drugs (topiramate, hydrochlorothiazide) that can trigger angle-closure. 7, 8, 9