Background: To evaluate the relationship and agreement between standard automated perimetry (SAP) and Matrix frequency doubling technology (Matrix-FDT) in subjects with ocular hypertension and healthy control subjects.
Methods: Forty-four eyes of 44 ocular hypertensive subjects and 29 eyes of 29 healthy age-matched control subjects were included in this prospective study. All participants underwent complete ophthalmic examination, including slit-lamp biomicroscopy, intraocular pressure measurement, pachymetry, and dilated fundus examination, and showed reliable visual field tests. One randomly selected eye of each participant was examined with SAP (Swedish Interactive Threshold Algorithm [SITA] Standard 24-2 test) and Matrix-FDT (24-2 threshold test), in random order. Correlations between global indices (MD, PSD), regions (2 hemifields, 4 quadrants, 6 sectors) and 52 single field positions were analyzed using Spearman's rank correlation coefficient.
Results: In both groups, mean deviation values of SAP and Matrix-FDT correlated significantly (OHT subjects: r = 0.47, p<0.005; healthy subjects: r = 0.68; p<0.001, respectively). Pattern standard deviation of SAP and Matrix-FDT showed no significant correlation in healthy subjects but correlated significantly in ocular hypertensive subjects (r = 0.45, p<0.005). In healthy subjects, a significant correlation between SAP and Matrix-FDT was shown in the supero-temporal and infero-temporal sectors of the disc (r = 0.40 and r = 0.38, p<0.05, respectively). In OHT subjects, supero-temporal, supero-nasal and nasal sectors correlated significantly (r = 0.49, 0.62 and 0.38, p≤0.01, respectively). The correlation pattern of individual visual field test locations appeared heterogeneous in both groups.
Conclusions: In both, ocular hypertensive and healthy subjects SAP and Matrix-FDT correlate well. In ocular hypertensive subjects, both techniques showed good correlation in the supero-temporal, supero-nasal, and nasal sectors of the disc. Poor agreement was found in the temporal, infero-temporal and infero-nasal disc sectors. This missing correlation might be related to early retinal nerve fiber layer damage in these regions of the disc, recognized by one of the visual field instruments.