Aim: When performing a recession with vertical transpositions of the insertions of the hori-zontal muscles in patients with A- or V-pattern, there is a risk for overcorrection in patients with relatively small angle of strabismus and almost straight eyes in up- or downgaze. Our impression was that a caudal or cranial partial tenotomy of the horizontal rectus could be suf-ficient to reduce the horizontal angle in gaze ahead and minimize the risk of overcorrection in the direction of gaze, either up- or downgaze, with the smallest horizontal deviation.
Methods: A retrospective evaluation of patients undergoing a caudal or a cranial partial tenotomy of the horizontal rectus was done, in the period between January 1996 and January 2006. Excluded were patients who had undergone previous surgery and patients with oblique-muscle surgery. We evaluated the reduction of the horizontal angle of strabismus, in gaze ahead and in 25° up- and downgaze.
Results: Fifty-two patients could be included, 16 patients with A-eso pattern, 12 with V-eso pattern, 7 with A-exo pattern and 17 with V-exo pattern. Their age at operation ranged from 2 to 80 years, median 16 years. The reduction of the horizontal angle in the working direction of the transposition, either up- or downgaze, was 8.1° (S.D. ± 4.5), in gaze ahead 6.2° (S.D. ± 4.5), and out of the working direction 3.3° (S.D. ± 4.4). Four patients had to undergo a short-term reoperation, one because of overcorrection and three because of undercorrections.
Conclusion: In patients with an A- or V-pattern and an almost straight eye position in either up- or downgaze, a partial tenotomy of the horizontal rectus is an effective treatment, with minimal risk of overcorrection.
- A-and V-pattern
- strabismus surgery