Surgical results in spinocerebellar ataxia (SCA)
Reviewed by Fiona Rowe

Patients with SCA frequently develop ocular motility abnormalities including nystagmus, abnormal smooth pursuits, dysmetric saccades, divergence paresis and ophthalmoplegia. Incidence of diplopia is higher in SCA type 3. The purpose of this study was to evaluate surgical responses and outcomes of bilateral medial rectus recessions in SCA esotropia in comparison to control of esotropia without neurological disorders. Five SCA type 3 patients and 10 control patients were compared. SCA was confirmed genetically by the presence of mutation in the ataxin-3 gene. Mean preoperative esotropia was 20PD versus 17.3PD in controls – non-significant. Final postoperative angle was 6.8PD versus 1.8PD respectively – significantly different. Mean corrected esotropia in primary gaze was 13.6PD versus 15.5PD – non-significant. Surgical success was defined as <8pD: success rate was 40% versus 80% with under correction in 60% versus 20% for SCA versus controls. Surgical response was 3.15 versus 3.87 PD/mm which was significantly different. Mean postoperative near-distance disparity was 8PD versus 1.1PD – a significant difference. The results confirm significant under correction of esotropia in SCA patients due to postoperative eso drift. The authors recommend a slight over correction of 5-10PD or adding a slanting procedure when planning strabismus surgery for SCA patients.

Surgical responses and outcomes of bilateral medial rectus recession in esotropia with spinocerebellar ataxia.
Chun BY, Freire MV, Cestari DM.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2019;56:266-70.