Correlation of Heidelberg Retinal Tomograph II and Humphrey Field Analyzer II SITA Fast Parameters at Baseline in the Glaucoma Imaging Longitudinal Study

Abstract

Abstract: : Purpose: To determine the relationship between optic disc and nerve fiber layer parameters and visual field status in glaucoma patients at the time of enrollment into the Glaucoma Imaging Longitudinal Study (GILS). Methods: The Humphrey Visual Field Analyzer II (HFA II) visual fields and Heidelberg Retina Tomograph II (HRT II) tomographs of all subjects enrolled in the GILS before 10/15/02 were studied. We excluded visual field tests with greater than 30% false positives or fixation losses and tomograms with topographical standard deviations of > 100 µm. Visual fields were subdivided into central quadrants and the mean deviation and number of points with a total deviation of greater than 4 dB in each region were calculated. The software incorporated into the HRT II was used to generate optic disc and nerve fiber layer parameters. Pearson correlation coefficients (r) were used to describe the association between visual field and HRT II parameters. Results: HRT II and HFA II were performed in 181 eyes of 118 subjects. 8 HRT II scans and 2 visual fields were of poor quality and excluded. In the remaining 171 eyes of 114 patients we observed moderately high correlations of optic disc and nerve fiber layer parameters (retinal nerve fiber layer (RNFL) cross-sectional area, mean RNFL thickness, and rim area) with visual field parameters in the corresponding area of the visual field. The strongest correlations were observed between the number of points with a total deviation of > 4 dB in the superotemporal quadrant and the RNFL cross sectional area (0.42, p < 0.001), mean RNFL thickness (0.40, p < 0.001) and rim area (0.45, p < 0.001) in the inferotemporal sector. Correlations between rim volume and visual field were weaker and less consistent. Conclusions: In this cross-sectional analysis of subjects at baseline, HRT II parameters correlated with visual field findings, both overall and by region. Whether changes in HRT II parameters precede visual field loss will require the longitudinal follow-up planned in the GILS.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • clinical (human) or epidemiologic studies: sys • optic disc