Abstract
Purpose: :
To assess the correlations between retinal nerve fiber layer (RNFL) thickness measured with scanning laser polarimetry (SLP) and visual field (VF) sensitivity measured with standard automated perimetry in primary open angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).
Methods: :
Fifty patients with POAG and 56 patients with PACG were examined with SLP (GDx VCC) and Humphrey VF analyzer 24-2 program. VF sensitivities were expressed as mean deviation (MD, in dB) and mean sensitivity (MS, in dB and unlogged 1/L scale). Correlations between RNFL thickness and VF sensitivity were estimated by Spearman’s rank correlation coefficient (rs), and multivariate quantile regression models (pseudo R2) to adjust for potential confounders. The correlations were determined globally and for six RNFL regions (superonasal, superotemporal, temporal, inferonasal, inferotemporal, and temporal) and their corresponding VF regions.
Results: :
The average RNFL thickness was 38.32 ± 7.71 µm in the POAG group and 38.64 ± 6.76 µm in the PACG group (P = 0.822). The correlation between RNFL thickness and MD was weaker in the PACG group (rs = 0.44, P <0.001, pseudo R2 = 0.13) than in the POAG group (rs = 0.54, P <0.001, pseudo R2 = 0.24). A similar trend of weaker correlation in the PACG group was observed when VF sensitivity was expressed as MS, both in dB and 1/L scale. For the six regions, the structure-function correlations were significant at the superotemporal (rs = 0.62), superonasal (rs = 0.56), inferonasal (rs = 0.54), and inferotemporal (rs = 0.52) regions in the POAG group (all P <0.001). The correlations were statistically significant only at the superotemporal (rs = 0.55) and inferotemporal (rs = 0.48) regions in the PACG group (both P <0.001).
Conclusions: :
The results suggest that structure-function correlations are higher in eyes with POAG than PACG. The disparity in the strength of structure-function correlations between POAG and POAG may be caused by differences in the pathophysiology of optic neuropathy between these 2 forms of glaucoma.
Keywords: imaging/image analysis: clinical • visual fields