TITLE:
Medial Rectus Muscle Advancement in Consecutive Exotropia
AUTHORS:
Stefano Pensiero, Maurizio Madonia, Fulvio Parentin, Dario Catalano
KEYWORDS:
Consecutive Exotropia; Medial Rectus Advancement; Strabismus Surgery
JOURNAL NAME:
Open Journal of Ophthalmology,
Vol.3 No.2,
May
14,
2013
ABSTRACT: Purpose: Consecutive
exotropia is a frequent consequence of surgery for convergent strabismus that
may develop at differing rates postoperatively. Several surgical options on
horizontal recti have been proposed, but none report a clearly standardized
amount of surgery. The present study provides further results of the medial
rectus muscle advancement. Methods: Twenty-eight patients, age
range 6 - 55 years, who had undergone unilateral or bilateral medial rectus advancement
to the physiological insertion, with or without contemporary unilateral lateral
rectus muscle recession, were included in the study. Factors leading to the onset of consecutive exotropia were
analyzed. Results: After 2 - 3 years,
the overall mean angle reduction was 21.3 prismatic diopters (PD) for distance
and 22.8 PD for near, with an effectiveness on near vision lower than expected.
Only in the 7 cases with a preoperatively larger exotropia at near (of at least
10 PD), the reduction was 17.0 PD for distance and 24.6 PD for near. In unilateral medial rectus muscle advancement, the mean reduction was 14.3
PD for distance and 16.3 PD for near; in bilateral advancement it was 25.8 PD
and 25.2 PD respectively. Conclusion: Medial
rectus advancement is preferable to other options, especially in cases with
convergence deficit, if no excess of divergence or limitation of bulb rotation is present, for which a
lateral rectus muscle recession is indicated. Unilateral and bilateral
surgeries are useful for exotropia of about 15 PD and 25 PD respectively. The effectiveness depends
weakly or not at all by the amount of the previously executed recession.