SUMMARY
Inferior oblique (I0) weakening is frequently performed for the correction of "V" pattern or to equalize forces in unilateral superior oblique palsy. Occasionally, a unilateral IO weakening is dane for the correction of hypertropia (HT) in primary position (PP) The authors analysed the effect of unilateral IO weakening on 23 patients with HT in PP. Ten of them were esotropic, 7 were exotropic and 2 patients didn 't show horizantal deviation in PP. The mean preoperative HT was 11.5 Δ ± 4.3 Δ. The postoperative HT was 3.1 Δ ± 3.5 Δ, a correction of 8.4 Δ ± 4.0 Δ. The mean preoperative overaction (from + 1 to +4) of the IO was 1.9 ± 0.9; postoperatively, it was 0.2 ± 0.6, a correction of 1.7 ± 0.9.
Neither HT or IO overaction reduction showed differences among the group of eso or exotropic patients. After the operation, only 5 patients presented an overaction of + 1 of the IO of the sound eye. The authors concluded that an unilateral IO weakening is an efficient procedure to treat HT in PP.
In 4 patients with associated dissociated vertical divergence, the surgical procedure was the recession and anterior transposition of the IO (according to Elliott & Nankin 's technique). The mean correction of the HT in PP was 17.75 Δ, much greater than the group who had undergone recession of the IO. In none of these cases it was observed hypotropia of the operated eye in PP.
Key words:
Inferior oblique; Unilateral weakening; Hypertropia