Table 1

Surgical approach to different types of intermittent exotropia

Indication for surgery

  1. Poor/worsening of control (Newcastle Control Score)

  2. Increasing angle of deviation

  3. Decrease in stereopsis for distance or near

  4. Double vision

  5. Parental demand

  6. Quality of life

Type of X(T)Surgical procedure
 1. Basic or simulated diveregence excess X(T)

  1. BLRc

  2. U/L R&R

  3. U/L LRc

  4. Augmented BLRc*

 2. Divergence excess X(T)

  1. BLRc

  2. Augmented BLRc

  3. BLRc +Faden suture (posterior scleral fixation suture) to B/L MR (for high AC/A ratio)

  4. BLRc +posterior pulley fixation of MR (for high AC/A ratio)

 3. Convergence insufficiency X(T)

  1. U/L R&R

  2. Augmented BLRc

  3. U/L or B/L MRs±slanting (greater resection of lower fibres of MR for near deviation and lesser resection of superior fibres)

  4. Improved R&R—LRc for distance and MRs for near deviation

  5. Slanted BLRc—inferior pole of insertion of LR is recessed for near while the superior pole is recessed for distance deviation

  6. Augmented BLRc

Resurgery†
 1. Residual/recurrent exotropia

  1. U/L or B/L MRs (post-BLRc)

  2. LR recession of other eye (post U/L surgery)

  3. LR rerecession (post small LR recession, but less predictable)

 2. Consecutive esotropia

  1. U/L or B/L MRc

  2. LR advancement‡

  • *Augmented BLRc: increasing surgical dosage by 1.0–1.5 mm for BLRc.

  • †Preferably explore the previously operated muscle and look for stretched scar, slipped muscle, soft-tissue adhesions or other abnormalities in case of residual/recurrent exotropia or consecutive esotropia.

  • ‡Dosage for LR advancement needs to be reduced due to greater effect per mm.

  • B/L, bilateral; BLRc, bilateral lateral rectus recession; LRc, lateral rectus recession; MRc, medial rectus recession; MRs, medial rectus resection; R&R, unilateral lateral rectus recession with medial rectus resection; U/L, unilateral; X(T), intermittent exotropia.