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E.O. Roberts, F.A. Proudlock, K. Martin, M. Reveley, I. Gottlob; Antisaccadic and Saccadic Eye Movements in Healthy Subjects and Schizophrenic Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2491.
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© ARVO (1962-2015); The Authors (2016-present)
Horizontal saccades (HS) and horizontal antisaccades (HAS) eye movements have been investigated widely in healthy subjects and schizophrenic patients. However little is known about vertical antisaccades (VAS) in both groups.
Seventeen healthy subjects and 12 schizophrenic patients performed saccadic and antisaccadic tests. Targets were presented on a rear projection screen horizontally and vertically at ±7° and ±14° for HS, HAS, VS, VAS tasks and repeated 4 times. Eye movements were measured with infrared oculography (EyeLink, 250Hz). Number of errors and saccadic latencies were calculated.
In the healthy group the number of errors (mean±SD) made during VAS (37.2±14.6%) was significantly higher than during HAS (20.6±13.9%, p<0.0001). The latency was slower for vertical saccades (VS) (179.6±20.8ms) compared to HS (172.5±17.5ms, p= 0.034) but not for VAS compared to HAS. In the schizophrenic group we found that the number of errors made during VAS (49.7±24.2%) was also higher than during HAS (37.7±21.4%, p=0.033). The latency was slower for VS (186.8±23.2ms) compared to HS (167.8±16.6ms, p=0.001) and also for VAS (246.8±48.2ms) compared to HAS (227.1±36.4ms, p=0.02). We found that the control group made fewer errors than the schizophrenic group for HAS (20.6±13.9% compared to 37.7±21.4%, p=0.02) and VAS (37.2±14.6% compared to 49.7±24.2%, p=0.049) but there was no difference in the performance of the saccadic tasks.
Both healthy and schizophrenic volunteers found it more difficult to make antisaccades along the vertical meridian than the horizontal meridian. Possible reasons for this could be a difference in attentional resources allocated to horizontal and vertical meridians for this task, differences in salience of horizontal and vertical meridians or the natural symmetry that exists along the horizontal meridian.
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