Ординатура / Офтальмология / Английские материалы / Strabismus Surgery and Its Complications_Coats, Olitsky_2007

19.2.1.1 Limbal Incision Closure Tips

Closure of a limbal incision should involve three distinct steps. If followed, the risk of inadvertent advancement of the plica is extremely low. The first step involves recognizing that the anterior aspect of a limbal flap often becomes coiled under the plica and that the surgeon must uncoil the anterior aspect the flap (>Fig. 19.7a). The second step is then to lightly grasp the underlying Tenon’s fascia near the corners of the limbal flap. Tenon’s fascia is lightly stretched anteriorly, resulting in uncoiling of the anterior-most aspect of the conjunctival flap (>Fig. 19.7b). Finally, sutures are placed in the corners of the conjunctival flap to complete the closure.

We have not been involved in the acute care of any patient who has had inadvertent advancement of the plica during strabismus surgery. Because infolded conjunctiva can fuse to adjacent conjunctiva [12] making repair very difficult, we recom-

Chapter 19

mend immediate surgery to correct the problem if diagnosed in the early postoperative period. We have treated several patients who sought treatment for plica advancement months or years after surgery. The complication can be identified by the presence of a beefy, thickened appearing medial conjunctiva (>Fig. 19.8). The eye may also become esotropic as a result of mechanical restriction produced by the shortened medial conjunctival fornix.

We have treated several patients with chronic advancement of the plica to the limbus. Early efforts to correct this problem involved attempting to dissect conjunctival/plica adhesions followed by uncurling of the infolded conjunctiva with reattachment of the anterior conjunctiva to its proper position near the limbus. These early attempts were immediately recognized as futile. The infolded conjunctiva was always found to be severely contracted and even when we were able to free these adhesions, the contracted conjunctiva was thickened, unsightly, and could not be effectively repositioned near the limbus. Even re-

Fig. 19.7a,b. Steps in the closure of a limbal incision. a Identify and uncoil the conjunctival flap. b Lightly grasp the underlying Tenon’s fascia near the corners of the flap and stretch it anteriorly, a step that

further uncoils the anterior aspect of the flap followed by placement of sutures in the corners of the conjunctival flap

Fig. 19.8. Appearance of the medial conjunctiva in a patient who experienced inadvertent advancement of the plica semilunaris to the limbus during strabismus surgery through a limbal incision 7 years earlier

Fig. 19.9. Improvement of postoperative appearance following surgical repair of longstanding advancement of the plica semilunaris to the limbus. (Same patient as in figure 19.8)

cession of the conjunctival flap was not effective. The plica has been markedly stretched in all of these cases as well. Because of this, even when released from the limbus, the plica tended to migrate back and reattach anteriorly after surgery.

Our more recent cases have enjoyed a greater measure of success. A large incision is fashioned at the limbus followed by removal of the medial conjunctiva and the plica almost to the caruncle (>Fig. 19.9). A small amount of the elongated plica is left intact medially to create a more anatomically normal appearance of the medial conjunctival angle postoperatively. We have found it necessary to suture the remaining plica to the sclera or to the medial rectus muscle insertion to reduce the tendency of this structure to attach more anteriorly during the postoperative period. Significant improvement can be achieved with surgery, though the cosmetic results are not perfect (>Fig. 19.9).

excise the conjunctiva ridge, leaving the underlying sclera bare. This technique typically produces excellent resolution and results in an excellent postoperative appearance.

To reduce the risk of conjunctival retraction and coiling following strabismus surgery through a limbal incision, several steps may be helpful, and may be especially useful in older patients and in others with attenuated conjunctiva. Additional sutures placed along the radial relaxing incisions in addition to sutures placed at the corners of the conjunctival flaps may be of value. The placement of a suture at the limbus midway between the two corner sutures can reduce tension on the corner sutures as well. The use of a small-diameter needle may result in less tearing of the conjunctiva during suture placement, reducing the risk of the suture tearing out of the conjunctiva postoperatively with resultant retraction and coiling.

19.2.2 Retraction and Coiling

Even following a properly closed limbal incision, the edges of the conjunctival flap can sometimes retract from the limbus before it has sufficiently formed an adhesion to the underlying sclera. While usually tolerated well, this complication can produce an unsightly ridge posterior to the limbus (>Fig. 19.10). The resulting ridge can be of significant cosmetic concern to the patient, and also can produce symptoms of ocular discomfort, resulting from tear film disruption. We usually recommend observation in the early postoperative period, because in most cases the thickened conjunctiva will become smooth and sufficiently flattened as the eye heals that no additional treatment is needed. If the problem persists for weeks or months following surgery, we have occasionally found it necessary to

19.2.3 Chemosis

Chemosis represents edema of the bulbar conjunctiva, which produces swelling of the conjunctiva around the cornea. It occurs to a mild degree in all patients undergoing strabismus surgery, but can occasionally be pronounced. The patient in Fig. 19.11 underwent bilateral, symmetric lateral rectus muscle recession in both eyes through a fornix incision. Five days after surgery, the right eye exhibited marked chemosis, while the left eye was healing normally. There was no evidence of periocular on intraocular infection. Chemosis of this severity is rarely seen following routine strabismus surgery. Chemosis can disrupt the suspensory attachments to the conjunctival fornix through hydraulic dissection. Prolonged prolapse of the conjunctiva may result in fusion of the folds together requiring excision [12].

Fig. 19.10. Perilimbal ridge produced by coiling and retraction of a limbal conjunctival flap following surgery

Fig. 19.11. Severe, benign unilateral chemosis in a patient who underwent symmetric bilateral strabismus surgery

Treatment is initially supportive, consisting of aggressive lubricating ophthalmologic ointments, with the addition of cellophane tents at night if the swollen conjunctiva protrudes anterior to the eyelids. Topical steroids are often prescribed and appear to be of value. This conservative treatment regimen will usually result in significant improvement or resolution within a few days to a week. When severe and prolonged, we have successfully managed chemosis by placement of temporary sutures in the conjunctival fornix to invaginate the prolapsed conjunctiva, as recommended by Malone and Tse [13].

pre and post invagination suture appearance of a patient with mild, but very symptomatic residual chemosis protruding over the lower eyelid 3 weeks after strabismus surgery. While hydration alone would have normally been satisfactory in this mild situation, this patient was returning to his home country overseas and there was a need to hasten resolution of the problem prior to his departure.

19.2.3.1Technique for Correction

of Prolapsed Inferior Conjunctiva

Topical proparacaine is applied to the conjunctival surface. After a sterile preparation of the lids, the lower eyelid is infiltrated with 2% lidocaine hydrochloride with 1:100,000 dilution of epinephrine. Two or three double-armed absorbable sutures, such as 4–0 chromic gut sutures or 6-0 Polyglactin 910TM (Vicryl®), are inserted in mattress fashion to reposition the prolapsed conjunctiva into the fornix of the lower eyelid. The needles are passed into the dome of the prolapsed conjunctiva, through the inferior fornix, exiting the skin 8–9 mm below the lash margin (>Fig. 19.12). The second pass is made several millimeters from the first and the two suture ends are then tied on the skin surface. Upon tightening the sutures, the prolapsed conjunctiva is invaginated and will re-form the inferior fornix. Malone and Tse [13], who used this technique to manage prolapsed conjunctiva after retinal surgery, described use of this technique for prolapsed upper fornix conjunctiva also, though we have not seen involvement of the upper conjunctiva following strabismus surgery. They also recommended temporary tarsorrhaphy in conjunction with placement of the mattress sutures. We have not found temporary tarsorrhaphy necessary, but rather rapid healing has been seen in our patients using the mattress suture technique alone. Figure 19.13 shows the

Fig. 19.12. Suture placement to invaganate protruding inferior conjunctiva. Double-armed absorbable sutures are passed into the dome of the prolapsed conjunctiva, through the inferior fornix, and exit the skin 8–9 mm below the lash margin. When the sutures are tightened, the prolapsed conjunctiva is invaginated to re-form the inferior fornix. [With permission from Malone TJ, Tse DT, Archives of Ophthalmology 108; 890–891. Copyright (c) (1990) American Medical Association. All rights reserved]

19.2.4 Pyogenic Granuloma

The term pyogenic granuloma is a misnomer, because the lesions are neither pyogenic nor granulomas. Histological examination of these lesions has found them to be composed of mixed acute and chronic inflammatory cells, with capillary proliferation in a lobular pattern [14]. Clinically, pyogenic granulomas appear as a fleshy red mass with relatively rapid growth (>Fig. 19.14). The lesion is a proliferative fibrovascular response to previous trauma including surgery. The lesions can be mistaken for suture granulomas, Tenon’s cysts, or tumors and are a recognized complication of many ocular surgeries where the conjunctiva is manipulated. Pyogenic granulomas have been described after pterygium excision, chalazia incision and drainage, placement of orbital implants, nasolacrimal duct probing with silicone tube placement, insertion of silicone punctal plugs, blepharoplasty, and eye muscle surgery [15–19].

The incidence of pyogenic granulomas has been reported as occurring after 1% of all conjunctival incisions and typically occurs 3–4 weeks after surgery. Espinoza and Lueder [20] reported pyogenic granuloma formation in 2.1% of strabismus operations. This rate is higher than our anecdotal experience, in which this complication is rare. In most cases, these lesions will resolve spontaneously. Many surgeons recommend the use

of topical steroids although their efficacy has not been proven (>Fig. 19.14). The average duration of treatment is 2–3 weeks. Surgical excision may be required for pyogenic granulomas that fail to resolve after topical treatment and/or observation alone. Reoccurrence following excision is extremely rare [20].

19.2.5 Prolapse of Tenon’s Fascia

Occasionally extrusion/exposure of Tenon’s fascia through the conjunctival incision occurs following strabismus surgery. This complication can be avoided by ensuring that the edges of the conjunctival incision are well opposed or sutured following surgery. If a large amount of Tenon’s fascia is noted to be extruding through the conjunctival incision at the end of the case, we will either excise the extruding Tenon’s fascia or place additional sutures in the conjunctiva to fully internalize the exposed fascia. Occasionally, however, a patient will present postoperatively with exposed Tenon’s fascia, sometimes with the exposed Tenon’s fascia stringing from the wound and even over hanging the eyelid (>Fig. 19.15). If the patient is cooperative, the exposed Tenon’s fascia can be trimmed flush with the conjunctival surface. Topical steroids can be used in cases where excision is not possible and resolution typically occurs within days or weeks.

19.2.6 Epithelial Inclusion Cyst

Subconjunctival epithelial inclusion cysts occur infrequently as a complication of strabismus surgery. They can occur anywhere in the operative field, but most commonly occur adjacent to conjunctival incisions or near the new muscle insertion into the sclera. Ullrich and coworkers [21] have even reported a patient with bilateral acquired epithelial cysts in the belly of the medial rectus muscles. Simple acquired conjunctival epithelial cysts are thought to arise from inclusion of conjunctival epithelial cells into the substantia propria or the sclera. Nests of conjunctival epithelial cells that have become deposited during strabismus surgery later proliferate, forming a central cavity and ultimately forming a visible cyst. The wall of the cyst is usually composed of nonkeratinized conjunctival epithelium and may contain goblet cells (>Fig. 19.16).

Epithelial inclusion cysts have a tendency to enlarge over time and thus removal of an epithelial inclusion cyst is recommended when the diagnosis is made or suspected. Untreated, inclusion cysts can persist indefinitely and can enlarge dramatically. Figure 19.17 demonstrates the anterior aspect of a large epithelial inclusion cyst present for more than 40 years following medial rectus muscle recession surgery. Prior to surgical excision, the patient’s ophthalmologist had performed

Fig. 19.16. Epithelial inclusion cyst lined with nonkeratinized conjunctival epithelial cells

Chapter 19

needle aspiration of the cyst on several occasions, with rapid recurrence. At surgery, the cyst extended well into the posterior orbit.

When an epithelial inclusion cyst forms at the site of muscle reattachment to the sclera, growth of the cyst can result in disruption of the muscle insertion [22], causing movement of the muscle insertion posteriorly, and recurrent strabismus. Failure to recognize that the muscle is attached to the cyst can result in detachment of the muscle with worsening of the patient’s strabismus [22]. Figure 19.18 demonstrates an epithelial inclusion cyst removed intact from an 18-year-old woman who had undergone four previous strabismus operations involving right superior rectus muscle. After her most recent surgical procedure, performed 7 years prior to our evaluation, she noted the gradual onset of a right hypotropia and retraction of her right upper eyelid. Examination revealed a right hypotropia, right upper eyelid retraction and proptosis with hypoglobus (>Fig. 19.18a). Computed tomography revealed the presence of a large cystic structure in the superior aspect of the orbit (>Fig. 19.18b). The anterior aspect of the cyst was found 12 mm from the limbus. The cyst extended more than 10 mm posteriorly and the superior rectus muscle was attached to the posterior aspect of the cyst (>Fig. 19.18c). Removal of the cyst followed by advancement and reattachment of the superior rectus muscle to the globe resulted in marked improvement of both her hypotropia and her lid retraction.

Epithelial inclusion cysts occur infrequently enough that studies to investigate their cause and to study surgical techniques to minimize their occurrence are not practical. Though we do not have evidence to support the following recommendations to reduce the risk of epithelial inclusion cyst formation, common sense would seem to support several useful concepts. First, we recommend creating conjunctival incisions in the most uniform, least disruptive manner possible. During closure of the conjunctiva, care should be taken to ensure that the conjunctival edges are reapproximated accurately, making sure that the edge of the conjunctival incision is not coiled into the wound. Care should also be taken when pulling suture through scleral tunnels created to attach the extraocular mus­ cles to the globe to reduce the risk of an epithelial inclusion cyst forming at the muscle insertion. We are concerned that, if

the conjunctiva becomes adherent to the suture and is pulled into the scleral tunnels, conjunctival epithelial cells may become deposited in the scleral tunnels resulting in later development of an epithelial inclusion cyst (>Fig. 19.19).

While very small epithelial inclusion cysts can be effectively removed through a small conjunctival incision placed adjacent to the cyst, we have found that most medium to large epithelial inclusion cysts are best removed through a standard limbal conjunctival incision, similar to the limbal incisions created for surgery on the rectus muscles. Limbal incisions are familiar to most strabismus surgeons, they facilitate excellent exposure of the cyst, and they allow the surgeon to maintain control of

Fig. 19.18a–c. Epithelial inclusion cyst following multiple operations on the superior rectus muscle. a Preoperative appearance demonstrating proptosis, hypoglobus and eyelid retraction. b Computed tomo­ graphy demonstrating a large cystic structure in the superior orbit. c Note that the superior rectus muscle is attached to the posterior edge of the cyst

Fig. 19.19. Dragging of conjunctiva into the scleral suture tunnels could implant conjunctival tissues in the scleral tract leading to later development of an epithelial inclusion cyst

adjacent muscles during excision, thereby reducing the risk of muscle injury. We recommend isolation of the adjacent muscle on a muscle hook to help ensure the safe removal of the cyst without accidental disinsertion of the muscle if the cyst is large and located close to the muscle. We have treated one case of a lost muscle that developed during removal of an epithelial inclusion cyst that went unrecognized by the surgeon until the postoperative period when the patient presented with a large consecutive deviation and duction deficit.

The goal of surgery should be to remove epithelial inclusion cysts intact. After creating a limbal incision, the conjunctiva and Tenon’s fascia overlying and adjacent to the lesion

are sharply dissected (>Fig. 19.20a). Care should be taken to avoid manipulating the cyst with forceps, as the cyst can easily be ruptured during manipulation. Once the cyst has been fully exposed, it should be carefully excised from the underlying sclera. Attachment of the cyst to the underlying sclera is typically very firm and care must be taken to transect these fine but firm attachments to the underlying sclera without rupturing the cyst (>Fig. 19.20b). Epithelial inclusion cysts that develop at the muscle insertion and result in migration of the muscle posteriorly are typically only attached to the sclera at the muscle insertion, and this attachment tends to be quite firm as well.

While removal of a conjunctival epithelial inclusion cyst intact seems a reasonable objective of surgery, we have had several cysts rupture during removal. When this occurs, we have excised all visible elements of the cyst, irrigated the operative site in an attempt to wash away any stray epithelial cells, and applied cautery to the sclera where the cyst was attached. Thus far, none have recurred, including those that have ruptured during removal. After removal of the cyst, the conjunctiva should be closed with interrupted absorbable suture (>Fig. 19.2c). Patients are placed on a combination steroid and antibiotic drop 4 times per day for 1 week. Healing of the conjunctiva generally occurs in a manner similar to conjunctival healing following standard strabismus surgery.

Hawkins and Hamming [23] described a simple office technique to treat small conjunctival inclusion cysts. Following administration of a topical anesthetic agent, a high temperature (2200ºF) battery-powered ophthalmic cautery unit was applied to the cyst under slit lamp visualization. It was applied directly to the surface of the cyst until fluid was released from the cyst and the base of the cyst was then cauterized. A combination steroid–antibiotic ointment was used postoperatively for 1 week. The procedure resulted in rapid resolution with no recurrence in the three patients they treated (>Fig. 19.21).

Freedman has described another method to remove epithelial inclusion cysts (personal communication with Richard Freedman). He suggests injecting the cyst with methylene blue dye. The contents of the cyst will drain through the injection site leaving the stained cyst wall easily visible. The cyst can then be readily removed with improved visualization (>Fig. 19.22). We have found this technique to be useful in selected cases.

19.2.7 Sudoriferous Cyst

We have seen several patients referred to us with chronic pain for months or years following strabismus surgery who had no external signs of ocular abnormalities. Surgery to correct residual strabismus, typically also associated with a concurrent duction limitation, has revealed the presence of a sudoriferous cyst in several cases. A sudoriferous cyst is an implantation cyst of sweat gland origin. These cysts presumably arise through implantation of cells from the accessory lacrimal gland or glands of Moll. They are lined by cuboidal epithelium that is similar to the parent gland or duct. Grossly, they may contain a clearyellow or viscous, brown-yellow material that may resemble an abscess in appearance, but will be culture negative. The lesions should be treated by complete surgical excision, which in our cases has also resulted in resolution of the chronic ocular discomfort/pain that our patients had experienced prior to surgical removal.

Fig. 19.21a,b. a Conjunctival cyst on the nasal conjunctiva of a patient’s right eye 5 months after strabismus surgery and b 2 months after the cyst was cauterized. (Reprinted from [23] Journal of AAPOS, volume 5, Hawkins AS, Hamming NA, Thermal cautery as a treatment

19.2.8 Subconjunctival Abscess

The occurrence and treatment of a subconjunctival abscess following strabismus surgery is discussed in detail in Chap. 22, and is reviewed here briefly. A subconjunctival abscess usually presents with pain that is in excess to that experienced by the typical postoperative patient, marked conjunctival injection and elevation of the overlying conjunctiva. An abscess is often visible and obvious through the overlying thin conjunctiva (>Fig. 19.23). When an abscess is diagnosed or suspected, surgical drainage should proceed as soon as possible. Drainage can be done in the office or in the operating room, depending upon the level of patient cooperation, patient age, and the size and location of the abscess. Inspection of the fundus with indirect ophthalmoscopy and slit lamp examination for evidence of intraocular infection is prudent. We have generally prescribed topical and oral antibiotics after abscess drainage. Moxifloxa-

for conjunctival inclusion cyst after strabismus surgery, pp 48–49, 2001, with permission from American Association for Pediatric Ophthalmology and Strabismus)

cin, a fourth-generation fluoroquinolone, is our antibiotic of choice because of its broad coverage and it ability to achieve therapeutic levels in the eye after oral administration [24].

19.2.9 Conjunctival Adhesions

Simpson and co-workers [25] described the unusual occurrence of broad adhesions between the palpebral and bulbar conjunctiva in a patient who underwent simultaneous surgery on the levator palpebrae superioris muscle of the upper eyelid and lateral rectus muscles. Recognizing that the raw conjunctival surfaces of the palpebral and bulbar conjunctiva could easily make contact after surgery and fuse together, they recommended that eyelid surgery not be performed at the time of strabismus surgery. We concur with this recommendation, if the palpebral conjunctiva is to be incised during lid surgery.

Fig. 19.22. Epithelial inclusion cyst walls stained with methylene blue dye (courtesy of Richard Freeman, MD)

Fig. 19.23. Subconjunctival abscess following strabismus surgery in a patient with diabetes mellitus

On the other hand, surgery that does not involve incision of the palpebral conjunctiva can be performed simultaneously, if indicated, and we have occasionally found it reasonable to perform lid and strabismus surgery simultaneously.

19.2.10 Primary Amyloidosis

Rodrigues and coworkers [26] reported a case of localized amyloidosis involving the conjunctiva overlying the lateral rectus muscle in both eyes of a 13-year-old boy following strabismus surgery (>Fig. 19.24). The lesions recurred following removal, requiring a second intervention to surgically remove the lesions, without further recurrence. The etiology of the lesions was unclear and the details of the strabismus surgical procedure were not available in their published report. While we are aware of cases of systemic amyloidosis involving the conjunctiva and extraocular muscles, we are not aware of any other reports of primary amyloidosis following strabismus surgery.

Chapter 19

19.2.11 Subconjunctival Foreign Bodies

Subconjunctival foreign bodies following strabismus surgery can be intentional and unintentional. Unintentional foreign bodies are unusual. Cilia that have fallen into the surgical site are the most common unintentional foreign bodies seen. They are generally asymptomatic, but we treated one patient who was so distressed by the appearance of cilia under the conjunctiva that we ultimately removed it. The most common foreign body that has been intentionally placed at the time of surgery is a nonabsorbable suture. While some strabismus surgeons have advocated routine use of nonabsorbable sutures for some surgical situations [27], we try to avoid permanent sutures when possible. We have seen several long-term problems associated with the use of absorbable sutures. The patient in Fig. 19.25 complained of the appearance of “worms” on the surface of his eyes, the result of a retained permanent suture that was coiled under the conjunctiva. We have seen Mersilene® sutures erode through the overlying conjunctiva months or years after surgery producing chronic ocular discomfort. We have treated several patients with a sterile abscess adjacent to a 6–0 Mersiline® suture, with the onset of symptoms month or years after surgery.

Fig. 19.24. Localized amyloidosis noted following strabismus surgery. (Reprinted from [26] Rodrigues MM, Cullen G, Shannon G. Primary localized conjunctival amyloidosis following strabismus surgery. Can J Ophthal 1976;11:177–179, with permission)

19.2.12 Conjunctival Buttonholes

Buttonholes most commonly occur during reoperation of a patient who has previously undergone strabismus surgery through a limbal incision or other ophthalmologic surgery involving the perilimbal conjunctiva. Following a previous limbal incision, the conjunctiva anterior to the muscle can be tightly adherent to the underlying sclera. Buttonholes can also be seen during primary or secondary strabismus repair in elderly patients with thin conjunctiva when surgery is performed through a fornix or limbal incision. Small buttonholes do not require repair. The conjunctival surface may appear irregular in the immediate postoperative period, but usually will have healed with a smooth and regular appearance when the patient is examined several months following surgery. It is our practice to close larger buttonholes with interrupted absorbable sutures, most common 6–0 plain gut suture. Though they are an unwanted complication, buttonholes are not generally associated with significant cosmetic or functional problems.

Fig. 19.25. Mersilene® suture coiled in the episcleral space that was visible to a patient more than 10 years after surgery as “worms” in his eyes

19.3 Scleral Complications

19.3.1 Grey Spot

The sclera posterior to the rectus muscle insertions is thinner than the surrounding sclera, averaging 0.3 mm in thickness [28]. After disinsertion of a rectus muscle, the dark color of the underlying choroid can often be seen through the thin sclera in this region. This is most obvious following disinsertion of a

medial rectus muscle. After recession of a rectus muscle, particularly the medial rectus muscle, a “grey spot” is often visible and its appearance can be quite distressing to some patients (>Fig. 19.26). The grey spot can be subtle or can be quite pronounced. We evaluated one patient who was so distressed by the appearance of a postoperative grey spot that her surgeon had attempted to correct the problem by placement of a pericardial graft to cover the thin sclera (>Fig. 19.27). The result was unsatisfactory, the pericardial graft required removal, and the patient was less distressed by the discoloration of her sclera, thereafter.

Advancement of Tenon’s fascia over the area of thin sclera as a primary or a secondary procedure appears to make the scleral grey spot less visible, though data on long-term success with this technique is lacking. We now frequently advance Tenon’s fascia to cover areas of particularly thin sclera posterior to the rectus muscle insertions when the grey spot is noted to be more prominent than usual intraoperatively and we believe that the problem will be a cosmetic issue postoperatively (>Fig. 19.28).

19.3.2 Scleral Ridge

Postoperative patients occasionally complain of a ridge or line that can be seen at the site of the original muscle insertion following a rectus muscle recession procedure. This most commonly occurs when a significant muscle stump is left on the sclera and produces irregularity of the overlying conjunctiva postoperatively. It is most likely to be of concern following recession of a lateral rectus muscle, in our experience (>Fig. 19.29). Patients commonly describe a “ridge,” “hole,” or “gutter” in the operated eye. This complication can be minimized by trimming the insertion stump flush with the sclera before closure of the conjunctiva.

Fig. 19.27. Unsuccessful attempt to cover a prominent “grey spot” using a pericardial graft. The thick graft was easily visible and ultimately migrated through the conjunctiva and was removed by the patient’s primary surgeon

Fig. 19.29. Obvious scleral ridge visible at the site of the original insertion following rectus muscle recession. This appearance can be minimized by dissecting the muscle stump flush with the sclera