Pseudosquint

Pseudostrabismus refers to the appearance of ocular misalignment in the presence of normal ocular alignment. It is one of the most common reasons babies and infants are referred to orthoptic clinics. A full, thorough assessment is needed to ensure there is no true squint. For orthoptists and students, recognising the key anatomical causes and knowing how to differentiate pseudostrabismus from manifest deviation is essential.

Why Pseudostrabismus Happens

A pseudosquint occurs due to facial features causing the appearance of a squint, despite the eyes being perfectly aligned. The most common anatomical factors include:

1. Prominent Epicanthic Folds

Babies often have broad nasal bridges with epicanthic folds that partially cover the nasal sclera. This makes the eyes appear as though they are turning inwards, creating the classic appearance of a pseudo-esotropia.

2. Wide Nasal Bridge

A flat, wide bridge reduces the amount of visible nasal sclera, again giving the impression of esotropia.

3. Hirschberg Reflex Misinterpretation

Parents frequently notice asymmetry in corneal light reflexes in photos, especially if the child’s head is tilted or the camera angle is off. This is a common reason for referral. And you may be shown many photos during the clinic appointment, this can help with your diagnosis. 

4. Positive Angle Kappa

A large positive angle kappa can mimic pseudo-exotropia. When the visual axis is slightly nasal to the anatomical axis, the corneal reflex appears displaced temporally, falsely suggesting an exotropia.

5. Asymmetrical Facial Features

Skewed medial canthi, lid anomalies, or facial asymmetry can create an impression of misalignment even when ocular axes are normal.

Clinical Assessment

1. History

Ask about:

• Parental observations

• Whether the appearance is constant or only in photos

• Any family history of strabismus or refractive error

• Prematurity or developmental concerns
  

2. Visual Behaviour and Fixation

Confirm that fixation is central and steady in each eye. Presence of fixation preference may indicate a true deviation.

3. Corneal Light Reflex Tests (Hirschberg/Krimsky)

In pseudostrabismus:

• Corneal reflexes are symmetrical

• No deviation appears when tested from multiple angles
  

4. Cover Test

In pseudostrabismus:

• Cover test is normal at both near and distance

• No movement detected on cover–uncover or alternating cover tests
  

5. Cycloplegic Refraction

Important to identify:

• High hypermetropia that may predispose to true esotropia

• Significant anisometropia
  

Even when pseudostrabismus is diagnosed, children with high refractive error may still require follow-up.

6. Examination of Facial Anatomy

Observe:

• Epicanthic folds

• Nasal bridge width

• Eyelid position

• Orbital asymmetry
  

Parental Reassurance and Education

Pseudostrabismus can cause significant anxiety for parents. Clear communication is crucial:

• Explain clearly that there is an appearance of a squint but the eyes are healthy and working well together. 

• Demonstrate the normal corneal reflexes or cover test findings.

• Reassure them that as their child grows and the nasal bridge develops, the appearance will likely improve.

• Encourage return if:

• the eyes begin to turn in/out more consistently

• one eye seems to drift intermittently

• visual behaviour changes

• photos show a consistent unilateral deviation
  

When to Review or Refer

Although pseudostrabismus is benign, some cases require monitoring:

• Strong family history of strabismus

• High hypermetropia or anisometropia

• Parental concern with photos showing possible unilateral deviation

• Prematurity or developmental delay
  

Children under 12 months with risk factors are often reviewed to ensure a true strabismus does not emerge.