Surgical Correction of V Pattern Intermittent Exotropia Without Inferior Oblique Muscle Overaction

Intermittent exotropia (IXT) is the most common type of strabismus which is a disorder of binocular eye movement control in which one eye intermittently moves outwards.Intermittent exotropia may be associated with difference in the horizontal deviation from the primary position to the upward or downward gaze giving A or V pattern In V-pattern intermittent exotropia (XT), there is an increase in the horizontal deviation as the eyes move from downgaze to upgaze.

Non-surgical treatment includes correction of refractive error, orthoptics, overcorrecting minus lenses and prismotherapy. Surgical options includes unilateral medial rectus muscle resection combined with a lateral rectus muscle recession or bilateral lateral rectus recession as in basic type IXT OR bilateral lateral rectus muscle recession as in divergent excess type OR bilateral medial rectus muscle resection as in convergence insufficiency.

Inclusion criteria

• Patients with V pattern intermittent exotropia (XT increasing by >10Δ in upgaze compared with Downgaze).
• No or minimal inferior oblique overaction on both sides (+1)
• Minimum follow-up period of 6 months after surgical correction of strabismus

Exclusion criteria

• Structural eye pathology.
• Significant neurodevelopmental delay.
• ntermittent exotropia without V pattern.
• Superior oblique under action.
• Duane syndrome.
• Less than 6 months follow up.