Clinical significance of saccade analysis in early active Graves' ophthalmopathy

To assess whether saccadic eye movements show distinct changes in patients with early active Graves' ophthalmopathy (GO), which could serve as a diagnostic tool for early detection and treatment.

Each of two prospective studies included 10 patients with early acute GO and 10 age- and sex-matched control subjects. In the explorative study (ES) 15 dynamic parameters of saccades were analyzed. In the comparative study (CS) only those parameters were evaluated, which in ES had shown significant differences between patients and controls. Horizontal and vertical saccades of 10 degrees, 20 degrees, and 40 degrees including a fatigue test were recorded binocularly using the induction scleral search coil.

The differences of saccadic dynamics between patients and controls were small, whereas intra- and interindividual standard deviations were large. In ES, 7.1% of the parameters showed significant differences at a level of P < or = 0.05. In CS, 2.1% of all parameters revealed repetitive significant differences. Despite statistical significance, individual data did not allow differentiation between patients and healthy individuals due to high standard deviations.

In early active GO no clinically relevant saccadic changes were detected. These findings may be based on adaptation of the central saccadic generator. Inclusion of patients with fibrotic muscle changes due to long-standing disease could explain the contrasting results of previous studies. Consequently, analysis of saccades does not serve as a diagnostic tool during early active GO.