Comparison between relative dispersion analysis of high-pass resolution perimetry and standard threshold perimetry

Purpose To evaluate the correlation of the dispersion index (DI) of relativ e dispersion analysis (RDA), a new high-pass resolution perimetry (HRP) ind ex, with other HRP indices and those of the Humphrey standard threshold per imeter (STP) parameters. Methods Sixty-eight eyes were randomly recruited. Thirty-one eyes were clas sified as glaucomatous (high intraocular pressure, abnormal visual field an d/or optic disc) and 37 as ocular hypertensives (high intraocular pressure, normal visual field, normal optic disc). All the subjects were examined wi th Humphrey Perimeter, program 30-2, and HRP, The HRP data were also analys ed with the RDA program. Statistical analysis was performed with Student's t-test, Pearson's r correlation coefficient, Mann-Whitney nonparametric tes t and Spearman correlation coefficient when appropriate. Results Within the entire sample significant correlations were found betwee n the RDA index (DI) and all the HRP indices (p < 0.001) and corrected patt ern standard deviation (p < 0.01), pattern standard deviation (PSD) (p < 0. 01), mean deviation (p < 0.05) and shortterm fluctuation (p < 0.05) of Sm. A stronger correlation was found in glaucomatous patients. In subjects with ocular hypertension DI was only weakly correlated with PSD, local deviatio n and form index. No difference in DI was found between glaucoma and ocular hypertension. Conclusion The DI of HRP has the theoretical capacity to detect localised i nhomogeneity of retinal sensitivity, but at present our data do not support this hypothesis. Before any clinical applications of this index further st udies are needed.