Adjustable suture strabismus surgery

We examined 333 patients between the ages of 11 and 70 years who underwent strabismus surgery with adjustable sutures over a ten-year period. The type of strabismus, the number and amount of adjustments, the postoperative drift, and complications were evaluated. A large percentage of patients required adjustment to obtain the desired postoperative position. The postoperative drift patterns were characteristic for each type of preoperative deviation and were similar to that reported for nonadjustable procedures. Adjustable suture techniques were especially helpful in selected horizontal deviations, vertical deviations, and the more complex strabismus problems. The complications from adjustable suture operations in this series were minimal.     

Topical anesthesia for strabismus surgery

Twenty-two adults underwent strabismus surgery under topical anesthesia over the past 4 years. Benefits of this technique include avoidance of certain hazards of general and retrobulbar anesthesia, the ability to adjust eye position to the patient's satisfaction on the operative table, and expanded options for patients unwilling to undergo general anesthesia. The major disadvantages are the possibility of increased patient discomfort. Patient selection is important.     

Artifacts of measuring during strabismus surgery

Several different artifacts can induce errors in measurements obtained during strabismus surgery. Fixating the severed rectus muscle stump with forceps during strabismus surgery can result in a temporary anterior displacement of the insertion. This may result in inaccuracies in determining the site to which the muscle is to be recessed. This displacement was quantified in a prospective masked manner and was found in some patients to result in as much as 1 mm of error. It can be prevented by measuring the recession prior to fixating the insertion stump with forceps; however, it cannot always be prevented by measuring from the limbus, which also introduces other artifacts due to geometric principles. An "advancement effect" occurs during a rectus muscle recession due to the mechanics of suture placement in the muscle. It was quantified in a masked manner and found to be approximately .5 mm in most cases. A "V" shaped deformity of the insertion stump may occur immediately adjacent to the forceps. This deformity frequently distorts the insertion by as much as several millimeters.     

Intraocular pressure variation during strabismus surgery

The changes in IOP during strabismus surgery were studied in 40 patients. In most, 37 eyes, there was a marked decrease of IOP during surgery and rapid return to initial levels of IOP. In 13 out of 14 eyes that underwent bilateral surgery, the IOP in the first operated eye returned to about baseline levels by the end of surgery on the second eye. No correlation was found between the changes in IOP and: the type of surgery, the operated muscles, the duration of surgery and anesthesia, or the patients' age. We surmise that the decrease of IOP is probably associated with the intensity of the massage of the globe during the surgery.     

Reoperation rate in adjustable strabismus surgery

Adjustable suture strabismus surgery may reduce the frequency of reoperations by reducing immediate postoperative over- and undercorrections. We reviewed 290 strabismus procedures performed with an adjustable suture technique. Thirty-five patients required additional surgery, for a reoperation rate of 9.7%. Reoperation frequencies for patients undergoing non-adjustable procedures average approximately 20% in our experience and in reported series. Our low reoperation rate with adjustable strabismus surgery supports our clinical impression that more accurate results are possible with this technique in appropriate patients.     

Refractive error changes following strabismus surgery.

Several uncontrolled, retrospective studies have suggested that permanent changes in refractive error can be seen following strabismus surgery. We prospectively enrolled 68 patients undergoing strabismus surgery for evaluation of pre- and postoperative cycloplegic refraction. In addition, the adult patients had computerized corneal topography recorded using the Corneal Modeling System, (Computed Anatomy, Inc, New York, NY). Pre- and postoperative refractions were compared using spherical equivalent and meridional equivalent (90- and 180-degree meridian). We found no significant change in the spherical equivalent between the pre- and postoperative measurements. However, a significant increase in the astigmatic power at 180 degrees (meridional equivalent at 180 degrees) was detected in both pediatric and adult patients. We did not observe any qualitative change in the corneal topography pre- and postoperatively. The change in astigmatic power at 180 degrees is equivalent to additional plus-cylinder correction at 90 degrees and was persistent throughout the 4-month postoperative period.