Perform forced duction testing to determine if a muscle is restricted prior to or at the start of surgery (see Chapter 42). Consider an alternative procedure if the opposing muscle is tight or inelastic (eg, thyroid eye disease, Duane syndrome).

If the patient has had prior eye muscle surgery, consider anterior segment blood supply. Plication can preserve anterior segment perfusion.² In general, do not operate on more than two rectus muscles simultaneously or more than three in total.

If resecting 5 mm or less, consider plication. Use the same surgical amounts for plication as for resection (see Chapter 42).

If operating on a patient with thin conjunctiva (typically older patients; ie, 60 years of age or older) or prior scarring, consider a limbal incision (see Chapter 43).

If operating on a young patient without scarring, consider a fornix incision (see Chapter 43).

If using an adjustable suture (see Chapter 48) with a resection procedure, consider resection combined with a hang back. For example, a 6-mm resection hung back 2 mm from the insertion could be left in place for a net effect of 4-mm resection, advanced to the insertion for a 6-mm resection, or hung back further for a smaller resection effect.

If operating on a vertical rectus muscle, counsel the patient about possible postoperative lid changes. Minimize these changes by disinserting the lid retractors from the rectus muscles as completely as possible during surgery. Lid changes are most commonly seen with inferior rectus resections >5 mm and superior rectus resections of 8 mm or more.

Isolate the rectus muscle on a Jameson muscle hook after creating the incision of choice (see Chapter 43). When isolating the superior rectus muscle, avoid incorporating the superior oblique. Similarly, when isolating the lateral rectus muscle, avoid incorporating the inferior oblique. Pass the muscle hooks just posterior to the insertion, hugging the sclera. Avoid large blind hooking movements.

Once the muscle is isolated, clean the muscle from its fascial attachments with sharp and blunt dissection. This is generally done more extensively for resection procedures compared with recessions. Have your assistant elevate the conjunctiva and put Tenon capsule on tension to facilitate dissection. Carry this dissection as far posterior as possible over the inferior and superior rectus muscle to help disinsert lid retractors. Avoid dissection into the orbital fat. Firmly rubbing a dry cotton tip applicator from anterior to posterior on the surface of the muscle can be helpful.

Once the muscle is cleaned and isolated, place a second large muscle hook (often a square hook) behind the first. The muscle should be under gentle tension and slightly elevated off the sclera. Using calipers, measure the amount of muscle to be resected and place a double-armed 6-0 Vicryl (or Polysorb) suture at this location in the typical fashion (see Chapter 43). Do not shift the suture anteriorly or posteriorly in the muscle tissue as the knots are tightened. If carrying out a large resection, consider placing a central “security” knot as the muscle will be under considerable tension once secured to the insertion (Figs. 45.1,45.2,45.3,45.4,45.5).