Top Flicker Fluctuation In Ocular Hypertension

Purpose: The early appearance of the TOP flicker defect in a large number of ocular hypertensive patients has been reported previously. The purpose of this study was to determine the reproducibility of these defects, Methods: Eleven normal and 30 ocular hypertensive eyes were examined three times: once with luminous threshold perimetry (TOP-S) and twice with flicker perimetry (TOP-F). Results: All examinations showed a mean defect (MD) < 2 dB and a loss of variance (LV) < 6 dB(2) with TOP-S. With TOP-F, one normal eye had abnormal MID and LV. Of the ocular hypertensive cases, 66.7% presented with one of the indexes over the cut-off level previously described. Both the indexes of 36.7% of the cases were higher at both examinations. In 46%, one of the indexes was higher at both examinations. The mean MID values were -0.34 +/- 1.1 dB with TOP-S (range: -2.51-1.39 dB) and 3.63 +/- 4.94 dB with TOP-F (range: -2.47-17.07 dB) (p < 0.001). The mean LV values were 2.07 +/- 1.69 dB(2) with TOP-S (range: 0.28-5.98 dB) and 17.75 +/- 17.86 dB(2) with TOP-F (range: 0.27-63.43) (p < 0.001). Threshold fluctuation for TOP-F was 1.13 +/- 1.10 dB (range: 0.05-3.70 dB) for normal eyes and 3.62 +/- 2.17 dB (range: 0.05-7.68 dB) for hypertensive cases (p < 0.001). Fluctuation was highly correlated with MD (r = 0.66). For MD values of 0 dB, fluctuation was 2.6 dB, and for MD = 10 dB, it was 5.5 dB. The correlation between MD and LV in TOP-S and TOP-F was low (r = 0.17 and 0.20, respectively). MD and square root of the Loss of Variance (sLV) correlated well in TOP-F (r = 0.83). Conclusions: TOP-F was abnormal in half the ocular hypertensive eyes. Similarly to luminous threshold perimetry, threshold fluctuation in this procedure increases with MD. Finally, NO and sLV showed a close relationship in TOP-F.