Purpose
Glaucoma progression analysis provided by Heidelberg retina tomography (HRT), the topographic change analysis (TCA), is based on the topographic change from baseline in the optic disc (ONH) and the peripapillary area. The purpose of this study was to compare structural progression by using different HRT parameters.
Methods
This is a retrospective longitudinal study. Thirty-two glaucomatous patients were enrolled into this study. All the included patient had to have a HRT follow-up of at least 3 years and 2 good quality HRT scans acquired at each visit. All the patients had at least 6 visual field examinations by Humphrey Field Analyzer in the last years and all of them had a visual field progression defined as a significant (p<0.01) VFI slope. Structural progression was evaluated by using cup shape measure (CSM), rim area (RA), rim volume (RV), TCA cluster area (CA), TCA cluster volume (CV). Data were analyzed by ANOVA test and Pearson’s r coefficient correlation.
Results
During the follow-up, CSM, RV and RA did not show any significant change, the mean Pearson’s r coefficient was 0.06, -0.02 and -0.34, respectively. However, when only the correlation with a r > 0.25 was considered, the r coefficient improved to 0.58, -0.54, -0.74, respectively. When TCA CA and CV were assessed, a significant (p<0.001) change was found among the baseline and the follow-up examinations. The mean value of the Pearson’s r coefficient was 0.86 and 0.81, respectively.
Conclusions
TCA CA and CV showed the highest capacity to detect glaucomatous structural changes.