Saccadic measurements in intermittent exotropia vs fusional amplitude
Reviewed by Fiona Rowe

The authors investigated the correlation between fusional convergence amplitude and saccades during the shift from exotropia to binocular fixation during the cover / uncover test. This was an observational study of 15 patients (six female, nine male) with intermittent exotropia. Eye movement measurements were recorded with the ViewPoint Eye Tracker system at a sampling rate of 350Hz. Patients were aged 18.1 ±11 years. Mean deviation on the eye tracker was 12.2 ±2.3 degrees in the dominant eye and 9.6 ±1.2 degrees in the non-dominant eye. Median fusional convergence amplitude was 14 degrees (range 0-60). Median deviation was 10.2 degrees (2.3-45) at distance and 14 degrees (9.1-45) at near. Fusional convergence amplitude showed a linear relationship with the primary saccade peak velocity and saccadic amplitude in the non-dominant eye. Deviation angle was significantly correlated with the primary saccade amplitude in the dominant eye. The authors suggest the saccade during re-fusion as the cover is removed, may be used to quantitively evaluate sensory and motor fusion. Limitations of this study include the lack of detailed sensory fusion assessment, small sample size and inclusion of some patients with prior strabismus surgery.

Correlation of saccade amplitude in patients with intermittent exotropia.
Kakene K, Mihara M, Tamura R, Hayashi A.
STRABISMUS
2022;30(3):121-31.