Figure 14-4 Allergic reaction to chromic gut. Allergic reactions are rarely seen with modern synthetic sutures such as polyglactin.

Epithelial Cyst

A noninflamed, translucent subconjunctival mass may develop if conjunctival epithelium is buried during muscle reattachment or incision closure (Fig 14-5). Occasionally, the cyst resolves spontaneously. Topical steroids may be helpful; persistent cases may require surgical excision. In some cases, the cyst is incorporated into the muscle tendon, so careful exploration is mandatory to identify this complication.

Figure 14-5 Postoperative epithelial cyst following right medial rectus muscle recession.

Conjunctival Scarring

Satisfaction from improved alignment may occasionally be overshadowed by unsightly scarring of the conjunctiva and the Tenon capsule. The tissues remain hyperemic and salmon pink instead of returning to their usual whiteness. This complication may result from the following:

Advancement of thickened Tenon capsule too close to the limbus. In resection procedures, pulling the muscle forward may advance the Tenon capsule. The undesirable result is exaggerated in reoperations, when the Tenon capsule may be hypertrophied.

Advancement of the plica semilunaris. During surgery on the medial rectus muscle using the

limbal approach, the surgeon may mistake the plica semilunaris for a conjunctival edge and incorporate it into the closure. Though not strictly a conjunctival scar, the advanced plica, now pulled forward and hypertrophied, retains its fleshy color (Fig 14-6).

Figure 14-6 Hypertrophy involving the plica semilunaris. (Courtesy of Scott Olitsky, MD.)

Treatment options include conjunctivoplasty with resection of scarred conjunctiva and transposition of adjacent conjunctiva; resection of subconjunctival fibrous tissue; recession of scarred conjunctiva; and amniotic membrane grafting.

Adherence Syndrome

Tears in the Tenon capsule with prolapse of orbital fat into the sub–Tenon space can cause formation of a fibrofatty scar that may restrict motility. Surgery involving the inferior oblique muscle is particularly prone to this complication because of the proximity of the fat space to the posterior border of the inferior oblique muscle. If recognized at the time of surgery, the prolapsed fat can be excised and the rent closed with absorbable sutures. Meticulous surgical technique usually prevents this serious complication.

Dellen

The term dellen (delle, singular) refers to shallow depressions and corneal thinning just anterior to the limbus; these occur when raised abnormal bulbar conjunctiva prevents the eyelid from adequately resurfacing the cornea with tear fluid during blinking (Fig 14-7). Dellen are more apt to occur when the limbal approach to EOM surgery is used. They usually heal with time. Artificial tears or lubricants may be used until the chemosis subsides.

Figure 14-7 Corneal delle subsequent to postoperative subconjunctival hemorrhage.

Anterior Segment Ischemia

The blood supply to the anterior segment of the eye is provided, in part, by the anterior ciliary arteries that travel with the 4 rectus muscles. Simultaneous surgery on 3 rectus muscles (as in a transposition procedure with simultaneous recession of an antagonist) or even 2 rectus muscles in patients with poor blood circulation may therefore lead to anterior segment ischemia (ASI). The earliest signs of this complication are cells and flare in the anterior chamber. More severe cases are characterized by corneal epithelial edema, folds in Descemet membrane, and an irregular pupil (Fig 14-8). This complication may lead to anterior segment necrosis and phthisis bulbi. No universally agreed-upon treatment exists for ASI. Because the signs of ASI are similar to those of typical uveitis, most ophthalmologists treat with topical, subconjunctival, or systemic corticosteroids, although there is no firm evidence supporting this approach.

Figure 14-8 Superotemporal segmental anterior segment ischemia after simultaneous superior rectus muscle and lateral rectus muscle surgery following scleral buckling procedure.

It is possible to recess, resect, or transpose a rectus muscle while sparing its anterior ciliary vessels. Though difficult and time-consuming, this technique may be indicated in high-risk cases. Staging surgery, with an interval of several months between procedures, may be helpful. Because the anterior segment is partially supplied by the conjunctival circulation through the limbal arcades, using fornix instead of limbal incisions may provide some protection against the development of ASI.

Change in Eyelid Position

Change in the position of the eyelids is most likely to occur with surgery on the vertical rectus muscles. Pulling the inferior rectus muscle forward, as in a resection, advances the lower eyelid upward; recessing this muscle pulls the lower eyelid down, exposing sclera below the lower limbus (Fig 14-9). Surgery on the superior rectus muscle is less likely to affect upper eyelid position.