Results of Unilateral Lateral Rectus Recession Surgery in 15 - 30 PD Intermittent Exotropia.

Purpose: To evaluate the surgical outcomes of unilateral lateral rectus muscle recession (ULR) with low surgical dosage in patients with intermittent exotropia (IXT) of 15 - 30 prism dioptres (PD).

Methods: We retrospectively analysed 92 eyes of 92 patients who underwent ULR surgery with the diagnosis of IXT of 15 - 30 PD at distance fixation between January 2017 and June 2019. ULR surgery of 6.5 mm was performed for exotropia of 15 - 20 PD, 7.5 mm for that of 20 - 25 PD, and 8.5 mm for that of 25 - 30 PD and postoperative results were evaluated at the 1st week, 1st month, 6th month, and the 2nd year. Orthophoria or IXT less than 10 PD was accepted as successful.

Results: The mean preoperative deviation angle at distance was 22.3 ± 4.4 PD. Mean postoperative deviation angles at distance were 2.5 ± 1.7, 3.9 ± 2.4, 6.5 ± 3.0, and 8.7 ± 3.1 at 1 week, 1 month, 6 months, and 2 years, respectively. The surgical success rate of ULR was 100, 96.7, 84.7, and 77.1% at the 1st week, 1st month, 6th month, and the 2nd year, respectively. In the long-term results, there were no complications such as lateral gaze incomitance, overcorrection, or deterioration in stereopsis.

Conclusion: Using the ULR technique, we were able to obtain effective surgical results in IXT with less surgical dosage and without any serious complications. ULR surgery can be used as an effective method in patients with IXT of 15 - 30 PD.