3.1 Goals

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  Minimize postoperative discomfort and scarring of the conjunctiva following strabismus surgery with a well-positioned and well-approximated conjunctival incision.

3.2 Advantages

Limbal conjunctival incisions allow greater exposure of the rectus muscle and surrounding structures, especially for reoperations and complex strabismus, and is more easily performed without a trained surgical assistant. However, a well-placed fornix incision has several advantages:

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  The incision and conjunctival scar are hidden by the upper or lower eyelid.

  
  
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  The incision does not require sutured closure in most cases, reducing surgical time and patient discomfort, except in the following scenarios:

  
  
  
  
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    The incision tears or extends to the limbus.

    
    
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    The patient has an underlying immune disorder.

    
    
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    The incision does not adequately cover the operative muscle and muscle suture.

    
    
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    Surgeon’s preference.

  
  
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  If sutured closure of the fornix incision is required, the sutures are located away from the limbus for less discomfort and foreign body sensation, which can occur after closure of a limbal incision.

  
  
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  Avoid scarring of the conjunctiva and Tenon’s capsule to the sclera anterior to the rectus muscle insertion to improve cosmesis and decrease the difficulty of reoperations if needed.

  
  
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  One incision allows access to multiple extraocular muscles:

  
  
  
  
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    An inferonasal fornix incision can access the medial rectus and the inferior rectus muscles.

    
    
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    An inferotemporal fornix incision can access the lateral rectus and inferior rectus muscles, as well as the inferior oblique muscle.

    
    
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    Inferior quadrant incisions are typically used for horizontal rectus muscle surgery.

    
    
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    A superonasal incision can access the medial rectus and superior rectus muscles, as well as the nasal aspect of the superior oblique tendon.

    
    
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    A superotemporal incision can access the medial rectus and superior rectus muscles, as well as the temporal aspect and insertion of the superior oblique tendon.

    
    
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    Fornix incisions should be used for oblique muscle surgery.

  
  
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  Radially oriented fornix incisions heal with little visible conjunctival scarring, but if greater exposure is required or if there is concern that the conjunctiva may tear easily, a circumferential fornix incision can be used, although the conjunctival scar may be slightly more visible by the surgeon after the incision heals.

  
  
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  With the use of locking toothed forceps, strabismus surgery with a fornix incision can be performed without a trained surgical assistant, as the locking forceps can be used to position the eye and provide exposure of the surgical field simultaneously.

  
  
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  The perilimbal conjunctiva may contribute to the anterior segment blood supply, so that a fornix incision preserves these anastamoses, possibly decreasing the risk of anterior segment ischemia. ¹

3.3 Expectations

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  Coverage of the operative extraocular muscle and its suture by the conjunctiva at the conclusion of surgery.

  
  
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  Little to no discomfort postoperatively, apart from reoperations with significant scarring.

3.4 Key Principles

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  Fornix incisions are created in the quadrant of the globe that provides access to the operative extraocular muscle(s).

  
  
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  Limbal incisions require sutured closure, which may cause more discomfort due to the presence of suture near the limbus, and can increase the risk of corneal dellen formation.

3.5 Indications

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  Fornix incisions can be used for most strabismus surgeries in the pediatric population.

  
  
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  If conjunctival scarring overlying a rectus muscle is causing restriction, a conjunctival recession may be indicated, which requires a limbal incision.

3.6 Contraindications

Patients with a history of multiple strabismus surgeries resulting in extensive scarring, or other prior ocular surgeries with placement of extraocular implants such as scleral buckles or glaucoma tube shunts, may necessitate limbal incisions for greater exposure of the operative muscle(s) and surrounding structures.

3.7 Preoperative Preparation

The decision for the type and location of the incision is made based on the planned operative muscle(s) and the patient’s ocular surgical history.

3.8 Operative Technique

3.8.1 Fornix Incision

The fornix incision is actually located on the bulbar conjunctiva between rectus muscles and becomes hidden in the fornix. Minimal scar formation occurs between the conjunctiva and Tenon’s capsule to the sclera, making reoperations less difficult if needed.

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  An eyelid speculum is placed. The eye is grasped with a 0.3-mm toothed forceps at the limbus, in the intermuscular quadrant where the incision is to be made, and then rotated to expose the quadrant.

  
  
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  The exposed quadrant of conjunctiva is inspected to ensure that it is not overlying a rectus muscle. Approximately 6 to 8 mm from the limbus, the conjunctiva is grasped and tented with two pairs of toothed forceps which are positioned circumferentially for creation of a radial incision (Fig. 3.1a). For a circumferential incision parallel to the eyelid margin, one or two pairs of forceps may be used to tent the conjunctiva.

  
  
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  Blunt Westcott scissors are positioned between the pairs of forceps on the conjunctiva with the blunt tips flushed against the globe and then snipped to create a conjunctival incision (Fig. 3.1b). If the first snip of the Westcott scissors does not reveal bare sclera, the forceps are used again to grasp the underlying Tenon’s capsule to create an incision, preferably at a 90-degree angle from the conjunctival incision.

  
  
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  The blades of the blunt Westcott scissors are closed and used to bluntly dissect the intermuscular space to bare sclera, orienting the curve of the blades with the curvature of the globe and keeping the blades open while withdrawing the scissors (Fig. 3.2).

  
  
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  Once the planned strabismus surgery is completed, the fornix incision can be reapproximated in most cases without sutured closure by grasping the eye at 6 o’clock with toothed forceps for an inferior incision and massaging the incision closed with the heel of a Stevens hook (Fig. 3.3).

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