Prospective comparison of global visual field indices and cluster progression in glaucoma and their relationship to structural changes

Abstract

PurposeGlaucoma diagnosis and follow up of progression is often based on structural and functional assessments. This study aimed to assess clustered progression in comparison to global indices and structural measures from HRT and OCT.Methods16 eyes of OHT and glaucoma patients with a minimum of 5 visual fields (HFA II i 24‐2) over a year were assessed prospectively. MD and VFI rates of progression were used for trend analysis. Linear regression of clusters defined by the Glaucoma Hemifield Test (GHT) was performed based on the mean threshold in each cluster. Rim Area (HRT 3) and mean parapapillary RNFL(SD‐OCT) analysis were assessed and correlated with functional clustered measures. Rates of progression were flagged as statistically significant if the gradients over time were negative with p<0.05.ResultsCluster analysis showed significant progression: 11 of 16 eyes in at least 1 cluster (68.75%) with an average rate of progression of ‐2.18 ± 2.2 dB/year. RNFL thinning was found in 12 of 16 eyes with an average rate of progression of 2.58 ± 1.43 μm/year. 7 out 16 eyes were progressing at HRT RA (43.75%) while 5 of 16 and 6 of 16 were progressing at VF VFI (31.25%) and VF MD (37.5%) respectively. The agreement between GHT Cluster and VF VFI and VF MD was 0.34 and 0.2, respectively. The best agreement was found between GHT Cluster and OCT RNFL (k= 0.61).ConclusionsVisual field clusters well detected spatial locations of sensitivity loss showing greater sensitivity than global indices (MD; VFI) and better concordance with structural changes. This suggests GHT clusters to be a sensitive method for the early identification of glaucomatous visual field loss.