Surgical Dose-Response Relationship in Patients with Down Syndrome with Esotropia: A Comparative Study

INTRODUCTION: This study is a comparison of the effectiveness of bimedial rectus recession surgery in patients with Down syndrome and those with normal neurological development.
METHODS: Records of patients with Down syndrome (age range: 2-17 years) who underwent bimedial rectus recession surgery for esotropia (ET) between April 2005 and April 2016 were reviewed retrospectively. A control group was also selected from age-matched patients with normal neurological development who underwent the same surgical procedure during the period. Ocular alignment was measured with the Krimsky test. Surgical success was defined as within 10 prism diopters (PD) of orthotropia 1 year after surgery. The case and control groups were compared in terms of preoperative and postoperative esodeviation angle at 1-year follow-up, the size of the bimedial rectus recession, and postoperative surgical success.
RESULTS: A total of 21 patients with Down syndrome and 42 control subjects were included. The groups did not differ in either preoperative (Down syndrome group: 39.73±8.47 PD; control group: 37.91±7.65 PD) or postoperative near deviation angle (Down syndrome group: 5.45±11.45 PD; control group: 2.36±7.13 PD) or size of bimedial rectus recession (Down syndrome group: 4.68±0.40 mm; control group: 4.78±0.38 mm). Surgical success had been achieved in 15 patients with Down syndrome (80.90%), and in 35 control patients (83.33%) at 1-year follow-up. There was a significant difference between the preoperative and postoperative deviation angles in both groups (p<0.05).
DISCUSSION AND CONCLUSION: Surgical success rate was similar in ET patients with or without Down syndrome who underwent bimedial rectus recession surgery.