Torsional Changes After Vertical Transposition of Horizontal Recti in V-pattern Exotropia Without Oblique Dysfunction

Area of Science:

• Ophthalmology
• Pediatric Ophthalmology
• Strabismus Surgery

Background:

• V-pattern exotropia is a common strabismus deviation in pediatric patients.
• Oblique muscle dysfunction can complicate the management of V-pattern exotropia.
• Vertical transposition of horizontal recti is a surgical option for V-pattern exotropia.

Purpose of the Study:

• To evaluate the efficacy of vertical transposition of horizontal recti in correcting V-pattern exotropia.
• To assess pattern collapse and torsional changes following the surgical procedure.
• To analyze outcomes in patients with and without preoperative amblyopia.

Main Methods:

• Prospective study of 32 patients with V-pattern exotropia and no oblique dysfunction.
• Vertical transposition of lateral recti (half or full tendon width) or unilateral transposition in amblyopic patients.
• Pre- and post-operative analysis of ductions, versions, pattern strabismus, disc foveal angle, and astigmatic axis.

Main Results:

• Significant pattern collapse was observed, with greater effect in full-tendon transposition.
• Pattern normalization occurred within 6 months in most patients.
• A strong correlation was found between preoperative V-pattern magnitude and postoperative pattern collapse; no significant torsional changes were noted.

Conclusions:

• Vertical transposition of horizontal muscles is an effective surgical treatment for V-pattern exotropia.
• The procedure leads to substantial pattern collapse with minimal impact on torsion.
• Preoperative extorsion in amblyopic patients with V-pattern exotropia remained unchanged post-surgery.