What is the likely diagnosis for a patient with bilateral transient episodes of opaque vision with a halo of light?

Bilateral Transient Episodes of Opaque Vision with Halos: Likely Diagnosis

The most likely diagnosis is intermittent angle closure (primary angle closure), representing episodes of transient pupillary block that spontaneously resolve before progressing to acute angle-closure crisis. 1, 2

Clinical Reasoning

The combination of bilateral presentation, transient nature, opaque (blurred) vision, and halos around lights is pathognomonic for intermittent angle closure episodes. 1

Key Diagnostic Features

Symptom Pattern:

• Halos around lights are caused by pressure-induced corneal edema, which occurs when intraocular pressure (IOP) rises during angle closure episodes 2, 3
• The bilateral nature strongly suggests primary angle closure disease rather than secondary causes, which tend to be unilateral 1
• The transient, self-resolving quality indicates intermittent pupillary block that breaks spontaneously before permanent damage occurs 1

Associated Symptoms to Elicit:

• Eye pain or headache during episodes 1, 2
• Eye redness 1, 2
• Nausea or vomiting 2
• Timing: symptoms often occur spontaneously or after pharmacologic stress (anticholinergics, mydriatic drops, dim lighting) 1

Risk Factor Assessment

Demographic Risk Factors:

• Female gender 2, 4
• Asian or Inuit ethnicity 2, 4
• Age over 50 years 2, 4
• Family history of angle-closure glaucoma 1, 2

Ocular Anatomic Features:

• Hyperopia 1, 2
• Shallow anterior chamber depth (central and peripheral) 1, 2
• Short axial length 1, 2
• Thick, anteriorly positioned crystalline lens 1, 2
• Steep corneal curvature 1, 2

Critical Examination Components

Immediate Assessment Required:

• Gonioscopy to assess iridocorneal angle and detect iridotrabecular contact (ITC) 1
• IOP measurement (may be normal between episodes) 1
• Pupil examination for mid-dilation, asymmetry, or poor reactivity 1
• Slit-lamp assessment of anterior chamber depth 1
• Refractive status assessment (hyperopia increases risk) 1

Fellow Eye Examination:

• Both eyes must be examined, as primary angle closure disease is bilateral 1, 4
• Wide open angle in the fellow eye suggests secondary rather than primary angle closure 1

Management Urgency

This patient requires urgent ophthalmologic referral even though symptoms are currently transient, because:

• Untreated fellow phakic eyes have approximately 50% risk of developing acute angle-closure crisis within 5 years 5, 2
• Acute angle-closure crisis can cause rapid glaucomatous optic neuropathy 1
• 18% of eyes become blind and 48% develop glaucomatous optic neuropathy within 4-10 years following untreated acute angle-closure crisis 1, 2

Definitive Treatment

Laser peripheral iridotomy (LPI) is the definitive treatment once the diagnosis is confirmed by gonioscopy showing ITC 5, 2, 4

• LPI relieves pupillary block and prevents progression to acute crisis 5, 2
• Both eyes require treatment given the bilateral nature of primary angle closure disease 5, 2
• Chronic miotic therapy alone is inadequate, as 40% of eyes treated only with miotics develop acute angle-closure crisis within 5 years 5

Important Pitfalls to Avoid

Do not dismiss transient symptoms as benign, even if the patient is asymptomatic at presentation—these represent warning episodes before potentially blinding acute attacks 1

Do not delay fellow eye prophylaxis after treating one eye, as acute attacks can occur within days 5

Avoid pupil dilation until after iridotomy is performed in patients with suspected occludable angles, as dilation can precipitate acute angle-closure crisis 1

Consider medication review for drugs that may precipitate angle closure: sulfonamides (including topiramate), anticholinergics, adrenergics, and inhaled bronchodilators (ipratropium, salbutamol) 1, 6, 7