Right-Angle Exotropia

Outcome of unilateral lateral rectus recession and medial rectus resection in primary exotropia

BACKGROUND

The purpose of this study was to measure the success rate of unilateral lateral rectus recession and medial rectus resection in primary exotropia.

METHODS

This is an interventional case series of 55 patients with primary exotropia (degree of deviation 15-85 PD), above the age of 5 years. Patients were treated in the Department of Ophthalmology, Jinnah Postgraduate Medical Center, Karachi, Pakistan, during the period of July 2009 to March 2010. All the patients underwent surgical procedure i.e., lateral rectus muscle recession (maximum up to 10 mm) and medial rectus muscle resection (up to 6 mm) of one eye, according to the Park's method. Surgery was done based on prism cover test measurements obtained at 6 m with appropriate optical correction in place. Patients were re evaluated at one day, one month, two months and six months post operatively. Final outcome was considered at the end of six months at which achievement of ≤10 PD of exotropia was the success. Data was analyzed on SPSS version 17.0.

RESULTS

We obtained success (≤10 PD) in 42 out of 55 patients (76.4%) and 13 out of 55 patients (23.6%) did not meet our criteria for surgical success (>10 PD). Analysis of success with the type of primary exotropia showed that success was achieved in 22 out of 24 cases of intermittent type (91.6%) and 20 out of 31 cases of constant type (64.5%)(P Value 0.019). The highest percentage of success was achieved in patients with the pre-operative deviation of ≤70 PD i.e., 93.3% (42 out of 45 cases), while none of the patients with the pre-operative deviation of >70 PD (10 out of 10 cases) achieved the criteria for success.

CONCLUSION

We conclude that pre-operative deviation is one of the strongest predictor for favorable surgical outcome. Therefore, eliminating the factors causing error in the correct determination of pre-operative deviation should improve the success and predictability of the surgical outcome. Despite the obstacles in the surgical management of strabismus, our results are encouraging.

Surgical correction of large-angle exotropia in adults

AIM

A retrospective and longitudinal review of the outcome of strabismus surgery for adults with large- and very-large-angle manifest exodeviations, using two-, three- and four muscle horizontal recti surgery with adjustable sutures.

METHODS

A total of 26 consecutive adult patients undergoing surgery for socially noticeable strabismus comprising five primary, 16 consecutive, and five secondary constant exotropias with a mean near deviation of 58 prism dioptres and a mean distance deviation of 55Delta were evaluated preoperatively and at various time intervals postoperatively. Surgery involved two muscles in seven cases, three muscles in 13 cases, and four muscles in six cases; and 25 of 26 had adjustable sutures. There was a horizontal preoperative ocular movement deficit in 17 that was asymmetrical in four cases.

RESULTS

Binocularity was restored in eight patients (31%), 20 (77%) were within 10Delta of orthotropia, and 24 (92%) were happy with their cosmesis. Two had symptomatic asymmetrical ocular motility deficits postoperatively following a two-muscle procedure and one required reoperation. A total of 19 patients undergoing three- or four-muscle surgery were asymptomatic postoperatively. A total of 22 patients had follow-up of 8 months or more.

CONCLUSION

In adults with large-angle manifest exodeviations, adjustable suture surgery involving three or more horizontal recti successfully restores primary position alignment, a high degree of patient satisfaction, and can be expected to be associated with a low incidence of symptomatic postoperative asymmetrical ocular movement deficits.

Unilateral four-muscle surgery for large-angle exotropia

Eight patients with large-angle exotropia and unimprovable poor vision in one eye were treated with conventional maximum horizontal rectus recession/resection plus weakening of both obliques of the poorly seeing eye. This appears to be a useful alternative to "supermaximal" recession/resection procedures, which are more likely to lead to deficient or restricted rotations. The effect is probably due to the release of additional sites of contracture that occur in the oblique muscles. The principal disadvantage is a small postsurgical hypertropia of the operated eye, for which routine infraplacement of both horizontal recti can compensate adequately.