[Frequency doubling perimetry in terminal visual field defects].

PURPOSE: To evaluate the Frequency Doubling Technology (FDT) in end-stage glaucomatous visual field defects.

METHODS

FDT (C-20 threshold test) was performed in 22 consecutive patients presenting an end-stage visual field defect with 24-2 SITA (0 dB in more than 75% and less than 100% of the visual field). Comparisons of the percentage of non-abolished points, topographic correlation, test duration and global indexes were performed between C-20 and 24-2 SITA test.

RESULTS

FDT sensitivity was 100%. C-20 test showed 13.7% more points with sensitivity greater than 0 dB compared to 24-2 test (P = 0.002). Two and a half less minutes were required for C-20 test performing (P<0.001). The mean value of Mean Defect was 11.48 dB better in FDT (P = 0,000). The mean value of the Pattern Standard Deviation was 5.37 dB (SD: 1.92) and 6.35 dB (SD: 3.61) for 24-2 and C-20 test respectively (P = 0.258). The inferotemporal quadrant was the best conserved in both perimetric strategies (Kappa agreement test value = 0.911; P<0.001).

CONCLUSIONS

FDT showed greater ability than 24-2 test for end-stage visual field defects evaluation, with the advantage of being less time-consuming. Very good topographic correlation between both strategies was found. Further studies evaluating FDT reproducibility in severe glaucomatous visual field damage are necessary.