What could be causing a patient's left eye pain when closing or keeping the eye closed, without redness, discharge, or itching, and how should it be managed?

Eye Pain on Closure Without Redness: Differential Diagnosis and Management

This presentation of unilateral eye pain specifically triggered by eye closure or keeping the eye closed, without redness, discharge, or itching, most likely represents either intermittent angle closure (if accompanied by transient visual symptoms) or a non-ophthalmologic referred pain syndrome, and requires urgent gonioscopy to rule out sight-threatening angle closure disease. 1, 2

Immediate Sight-Threatening Consideration

Intermittent Angle Closure

• Pain triggered by eye closure can represent intermittent pupillary block, as the mid-dilated pupil position during drowsiness or dim lighting precipitates transient angle closure episodes 2
• The absence of redness does NOT exclude angle closure—patients with intermittent episodes may appear completely normal between attacks 2, 3
• Critical associated symptoms to elicit: transient blurred vision, halos around lights (from pressure-induced corneal edema), headache, or episodes triggered by dim lighting or stress 4, 2
• Untreated intermittent angle closure carries a 50% risk of acute angle-closure crisis within 5 years, with 48% developing glaucomatous optic neuropathy and potential blindness 1, 2

Required Urgent Evaluation

• Gonioscopy is mandatory to assess for iridotrabecular contact (≥180 degrees indicates primary angle-closure suspect) 4, 2
• Measure intraocular pressure (may be normal between episodes) 4, 1
• Assess anterior chamber depth on slit-lamp examination 4
• Check refractive status (hyperopia increases risk) 4, 2

Alternative Diagnoses for Pain Without Redness

Referred Pain Syndromes

• Trigeminal neuralgia can manifest as periocular pain triggered by specific movements including eye closure 5
• Migraine or cluster headache may present with retro-orbital pain, though cluster headaches typically cause autonomic symptoms 5
• Sinusitis (particularly ethmoid or sphenoid) can refer pain to the eye region 5

Ocular Surface Disease

• Recurrent corneal erosion causes sharp pain on eye opening (not closure), but can occasionally cause discomfort with lid movement 6
• Dry eye disease typically causes burning rather than pain, and would be expected to have some conjunctival injection 6

Neurologic Causes

• Optic neuritis presents with pain on eye movement (not specifically closure), typically with vision loss and relative afferent pupillary defect 6, 3
• Increased intracranial pressure can cause positional headache but rarely isolated eye pain 5

Management Algorithm

Step 1: Rule Out Angle Closure (Urgent)

• Ask specifically about: halos around lights, transient blurred vision that resolves, bilateral symptoms, family history of glaucoma, hyperopia 2
• Examine for: shallow anterior chamber, hyperopic refraction, mid-dilated pupil 4
• Perform gonioscopy immediately—this is the only way to definitively assess angle anatomy 4, 2
• If iridotrabecular contact ≥180 degrees is present: refer urgently to ophthalmology for laser peripheral iridotomy in both eyes 2, 7

Step 2: If Gonioscopy Normal, Consider Referred Pain

• Assess for sinus tenderness, temporal artery tenderness (if age >50), neurologic deficits 5
• Consider trial of topical lubricants if mild surface disease suspected 4
• Refer to neurology if trigeminal distribution pain or headache pattern suggests neurologic etiology 5

Critical Pitfalls to Avoid

• Never dismiss transient symptoms as benign—intermittent angle closure episodes are warning signs before potentially blinding acute attacks 2, 7
• Do not dilate the pupil until after angle closure is ruled out by gonioscopy, as dilation can precipitate acute crisis 2, 7
• Pain without redness does not exclude serious pathology—acute narrow-angle glaucoma is a vision-threatening emergency that can present with a quiet eye initially 5, 3
• Do not delay ophthalmology referral if any suspicion of angle closure exists, as the natural history without treatment includes 18% risk of blindness within 4-10 years 1

Specific Red Flags Requiring Same-Day Ophthalmology Evaluation

• Any history of transient visual blurring or halos 2
• Hyperopic refractive error with shallow anterior chamber 4, 2
• Family history of angle-closure glaucoma 4, 2
• Age >50, female gender, Asian ethnicity (demographic risk factors) 2