Regional Correlation of Structure and Function in Glaucoma, Using the Disc Damage Likelihood Scale, Heidelberg Retina Tomograph, and Visual Fields

Abstract

To evaluate relationships between the Disc Damage Likelihood Scale (DDLS), global and sectoral structural parameters provided by the Heidelberg Retina Tomograph (HRT), and global and regional functional loss in visual field (VF) testing. Consecutive observational case series. One hundred ten eyes from 110 patients categorized as glaucoma, glaucoma suspect, or normal. Participants were examined clinically to grade the DDLS score and were tested with HRT and Swedish Interactive Threshold Algorithm standard 24-2 VF tests. All tests were performed within 6 months of each other by examiners masked to the other findings. For each patient, the eye with the worse mean deviation (MD) of the VF test was enrolled in the study. Each field was divided into 6 sectors based on a published scheme, and the MD for each sector was calculated. The relationships among clinical DDLS score, HRT parameters, and VF indexes were analyzed by correlation coefficients and linear regression analysis. The relationship between the DDLS score, global and sectoral optic disc (HRT) parameters, and global and sectoral VF MDs was evaluated. The DDLS showed significant correlation with all global and sectoral VF indexes (r = -0.39 to -0.62, all Ps < 0.0001) and with sectoral rim area HRT measurements (r = -0.27 to -0.51, all Ps < 0.006). The DDLS correlated most strongly with superior and inferior regional data from HRT and VF, and less well with temporal and nasal data. Heidelberg Retina Tomograph rim area and rim volume were the only HRT parameters to correlate moderately with global VF MD (r = 0.30, P = 0.0018, and r = 0.28, P = 0.0030, respectively). Sectoral HRT rim area correlated moderately strongly with the corresponding sectoral VF MDs in the superior and inferior sectors (r = 0.35-0.46, P = <0.0001-0.04). Clinical disc assessment and laser tomographic data that determine the state of the neuroretinal rim are associated with sensitivity loss in VF testing in corresponding regions.