7.1 Patient History Leading to the Specific Problem

The patient is a 64-year-old African American woman who underwent a transconjunctival lower eyelid blepharoplasty performed under general anesthesia 1 month previously; she complains of double vision since the surgery (Fig. 7-1). She became aware of this problem in the recovery room. The diplopia has improved slightly since the surgery and is not associated with any loss of vision or discomfort. She is otherwise completely healthy and has no history of ophthalmic problems other than wearing reading glasses.

7.2 Anatomic Description of the Patient’s Current Status

By report from the referring surgeon, the procedure was remarkable for significant bleeding in the area of the nasal fat pocket of the right lower eyelid that required vigorous cautery and retraction of the tissues to control (Fig. 7-2). Her postoperative course was said to be remarkable for significant swelling and bruising of the right lower eyelid that has now almost completely cleared. Ophthalmologic exam discloses 20/20 vision in both eyes. Pupils, intraocular pressure, and dilated retinal examination are normal. Motility examination shows that the patient has difficulty elevating the right eye especially in the adducted position (looking to her left). Forced duction testing performed with topical anesthetic was normal. The diagnosis is palsy of the inferior oblique muscle.

7.3 Recommended Solution to the Problem

We will approach this problem as the surgeon encountering it in the recovery room. This assumes that the patient is fully awake and cooperative.

• 
  

  Perform a basic assessment of the patient’s visual acuity.

  
  
• 
  

  Examine the patient’s ocular alignment and motility.

  
  
• 
  

  Consider forced duction testing.

7.4 Technique

Check the patient’s vision one eye at a time. This is easily accomplished with a pocket vision screener or “near card,” which is typically calibrated from 20/20 to 20/800. Allow the patient to hold it at a comfortable reading distance. If the patient wears reading glasses or bifocals for near vision correction (as do most individuals over the age of 40), be certain that these are used. If a near card is not available, use a magazine or newspaper, which is approximately 20/50 vision.

Check the ocular alignment by having the patient look at a penlight held approximately 2 feet away. With normal alignment, the light reflexes will be centered at exactly the same spot on the pupil of each eye (Fig. 7-3). With a unilateral exotropia, the light reflex will be decentered nasally (Fig. 7-4) as compared to the normal eye, while in esotropia the reflex will be decentered temporally (Fig. 7-5). Likewise, with a hypertropia the reflex will be decentered inferiorly on the cornea and in hypotropia it will be seen more superiorly than in the uninvolved eye.

Check the patient’s motility in the cardinal positions of gaze (Fig. 7-6). In medial gaze, the edge of the iris will normally be slightly hidden by the soft tissues of the medial canthus (Fig. 7-7). In lateral gaze, the temporal limbus will typically just reach the lateral canthus (Fig. 7-8). In downgaze and upgaze, it is normal for the eyes to move about 45 degrees from the midline (which would put a light reflex just outside of the upper or lower limbus, respectively). Upgaze decreases as patients age and by 94 it is normal to be able to look upward only 16 degrees. Of course, lid and conjunctival edema may obscure these findings, making these observations more difficult.

If a motility defect is suspected, the physician may decide to perform forced duction testing. First, apply a drop of a topical ocular anesthetic. Next, apply a cotton-tipped applicator soaked in 2% xylocaine for 30 seconds just outside the corneoscleral limbus 180 degrees opposite to the direction of the suspected underaction (Fig. 7-9a). For instance, if the right globe fails to fully rotate inferiorly, place the applicator near the corneoscleral limbus of the right eye at the 12 o’clock position. Next, grasp the conjunctiva at this position near the limbus with a small toothed forceps and rotate the eye inferiorly (Fig. 7-9b). The eye should easily and fully move to the normal end point of gaze. Difficulty moving the eye suggests a restrictive process such as entrapment in a fracture or orbital edema and hemorrhage. A false-positive result may be found, however, in an anxious patient who may resist the examiner’s attempt to move the eye. If the eye can be moved easily into the field of obvious underaction, a paretic muscle is suspected.