A new chart to improve the efficiency of glaucoma detection by oculokinetic perimetry

Oculokinetic perimetry (OKP) has been proposed as a method to screen for glaucomatous visual field defects but its use is limited by a high false positive rate. The standard hand-held screening OKP chart uses 26 points. The spiral arrangement of numbers with this chart allows loci to be tested close to fixation but may contribute to the high false positive rate. We have therefore designed and assessed a simplified OKP chart with 22 numbers arranged circumferentially around a central target. The positions of the numbers are such that points between 12 degrees and 16 degrees from fixation are tested in all quadrants. Loci closer to fixation are not tested. Fifty eyes from 50 patients with glaucoma and 50 eyes from 50 patients with normal fields were tested with both charts. Of the patients with glaucoma 88% gave a positive result with the 26-point chart and 90% gave a positive result with the 22-point chart. The false positive rate of OKP in patients without field loss was 12% with the 26-point chart and 0 with the 22-point chart (0.02 > p > 0.01). We therefore propose a modification of the existing OKP chart which reduces the false positive rate in glaucoma detection.