What is the most appropriate next step to diagnose a patient with a wandering eye and intermittent head tilting?

Cover-Uncover Test is the Most Appropriate Next Diagnostic Step

The cover-uncover test (Option B) is the most appropriate next step to diagnose strabismus in a patient presenting with a wandering eye and compensatory head tilting. This test directly assesses binocular alignment and can detect both manifest and latent deviations that characterize strabismus 1.

Why Cover-Uncover Test is the Correct Choice

Primary Diagnostic Tool for Strabismus

• The cover-uncover test is specifically recommended as the primary method for evaluating binocular alignment in patients with suspected strabismus 1.
• This test can identify the type of deviation (esotropia, exotropia, hypertropia) and whether it is constant or intermittent 1, 2.
• The clinical presentation of a "wandering eye" with compensatory head tilting is classic for strabismus, making alignment testing the most direct diagnostic approach 1.

Critical Examination Sequence

• Sensory tests should ideally be performed BEFORE cover testing to avoid dissociating the eyes, but when strabismus is already suspected based on observation, the cover-uncover test becomes the confirmatory diagnostic step 2.
• The prism and alternate cover test measures the total deviation (both manifest and latent components) and is more sensitive than simple observation 2.
• For patients unable to participate in sophisticated testing, the corneal light-reflection test (Hirschberg test) can estimate alignment, but cover testing remains superior when feasible 1.

Why Other Options Are Less Appropriate

Fundus Examination (Option A)

• Fundus examination is part of the comprehensive strabismus evaluation but is performed after establishing the diagnosis of strabismus through alignment testing 1.
• While fundus examination can detect ocular torsion in cases of vertical strabismus or skew deviation, it does not directly diagnose the primary alignment problem 1.
• This test would be indicated later to rule out secondary causes or assess for complications, not as the initial diagnostic step 1.

Retinoscopy (Option C)

• Cycloplegic retinoscopy/refraction is an important component of strabismus evaluation to detect refractive errors (particularly high hyperopia or anisometropia) that may contribute to accommodative esotropia 1.
• However, retinoscopy does not directly assess ocular alignment or diagnose strabismus itself 1.
• This test is typically performed as part of the comprehensive evaluation after confirming the presence of strabismus 1.

Clinical Reasoning Algorithm

Step 1: Confirm Strabismus Diagnosis

• Perform cover-uncover test to detect manifest deviation 1.
• Perform alternate cover test to measure total deviation (manifest plus latent) 1, 2.
• Document the direction of deviation (horizontal, vertical, or torsional) and whether it is constant or intermittent 1, 2.

Step 2: Assess Pattern and Severity

• Measure deviation at distance and near fixation 1.
• Evaluate in different gaze positions to detect incomitance 1.
• Assess head posture and compensatory positioning 1.

Step 3: Complete Comprehensive Evaluation

• Perform sensory testing (stereopsis, fusion) 1.
• Conduct cycloplegic refraction to identify refractive contributions 1.
• Perform fundus examination to rule out structural abnormalities 1.

Important Clinical Pitfalls to Avoid

Examination Sequence Errors

• Do not perform monocular occlusion tests (like visual acuity or retinoscopy) before assessing binocular alignment in suspected intermittent strabismus, as this can dissociate the eyes and interfere with accurate assessment 2.
• However, when strabismus is already clinically apparent (wandering eye), this concern is less critical, and cover testing can proceed directly 2.

Single Examination Limitation

• Do not rely on a single examination to characterize strabismus fully, as fusional control can vary substantially between visits, particularly in intermittent forms 1, 2.
• The deviation may not be manifest during examination if the patient is maintaining good fusional control at that moment 2.

Missing Red Flags

• Always assess for secondary causes including restrictive disorders, cranial nerve palsies, or increased intracranial pressure, particularly if onset is acute or associated with neurological symptoms 1.
• In cases with vertical deviation and head tilt, distinguish between superior oblique palsy and skew deviation, as the latter requires urgent neuroimaging 1.