Correlation between the Peripapillary Retinal Nerve Fiber Thickness and Visual Field Mean Defect in Pseudoexfoliation Glaucoma

Abstract

Objective: To discuss the correlation between the peripapillary retinal nerve fiber layer (RNFL) thickness and the visual field mean defect in different periods of pseudoexfoliation glaucoma (PXG). Methods: This was a clinical case control study. In the study, samples were selected consecutively from patients who were hospitalized in the Glaucoma Department of the First Hospital of Shijiazhuang from January 2013 to January 2018. The PXG group included 97 eyes of 97 patients who were divided into an early PXG group (28 eyes), a medium PXG group (27 eyes), and a late PXG group (42 eyes). The normal control group consisted of 32 eyes of 32 people who were matched for age, gender and refractive error. All subjects underwent spectral domain optical coherence tomography (SD-OCT) scans to measure peripapillary RNFL thickness in every quadrant. The SD-OCT and the visual field measurements among the different groups were compared using analysis of variance, and the correlation between the average RNFL thickness and visual field defects were analyzed with a Pearson correlation. Results: The average RNFL thickness in the normal control group, and the early, medium and late PXG groups was 104±11 μm, 92±14 μm, 82±12 μm, and 54±18 μm, respectively. The difference between the 4 groups in nasal, nasal superior, temporal superior, temporal, temporal inferior, nasal inferior quadrants and the average RNFL thickness were all statistically significant (F=24.38, 36.40, 47.84, 8.70, 95.46, 54.75, 82.28, all P<0.001). The differences between the normal control group and the early PXG group in the temporal superior, temporal inferior, and nasal inferior quadrants and the average RNFL thickness were statistically significant (all P<0.05). The differences between the normal control group and the medium PXG group in the nasal, nasal superior, temporal superior, temporal inferior, and nasal inferior quadrants and the average RNFL thickness were statistically significant (all P<0.05). The differences in RNFL thickness between the normal control group and the late PXG group in every quadrant were statistically significant (P<0.001). The average RNFL thickness was positively correlated with visual field mean differences in the medium PXG group and the late PXG group (r=0.404, P=0.037; r=0.582, P<0.001). Conclusions: The average peripapillary RNFL thickness is positively correlated with visual field mean differences in the medium and late PXG eyes. The changes of peripapillary RNFL thickness can be monitered by SD-OCT, which can be used as an important reference index for the status and follow-up of PXG. Key words: optical coherence tomography; pseudoexfoliation glaucoma; peripapillary retinal nerve fiber layer thickness; visual field mean defect; correlation