Diagnostic Power of Macular Retinal Thickness Analysis and Structure-Function Relationship in Glaucoma Diagnosis Using SPECTRALIS OCT

Aims: To evaluate the diagnostic power of the Posterior Pole Asymmetry Analysis (PPAA) from the SPECTRALIS OCT in glaucoma diagnosis and to define the correlation between the visual field sensitivity (VFS) and macular retinal thickness (MRT).

Methods: 90 consecutive open-angle glaucoma patients and 23 healthy subjects were enrolled. All subjects underwent Visual Field test (Humphrey Field Analyzer, central 24-2 SITA-Standard) and SD-OCT volume scans (SPECTRALIS, Posterior Pole Asymmetry Analysis). The areas under the Receiving Operating Characteristic curve (AROC) were calculated to assess discriminating power for glaucoma, at first considering total MRT values and hemisphere MRT value and then quadrant MRT values from 16 square cells in a 8 x 8 posterior pole retinal thickness map that were averaged for a mean retinal thickness value. Structure function correlation was performed for total values, hemisphere values and for each quadrant compared to the matching central test points of the VF.

Results: The AROCs ranged from 0.70 to 0.82 (p < 0.0001), with no significant differences between each other. The highest AROC observed was in inferior nasal quadrant. The VFS showed a strong correlation only with the corresponding MRT value s for quadrant analysis: Superior Temporal (r = 0.33, p = 0.0013), Superior Nasal (r = 0.43, p < 0.0001), Inferior Temporal (r = 0.57, p < 0.0001) and Inferior Nasal (r = 0.55, p < 0.0001).

Conclusion: the quadrant analysis showed statistically significant structure-function correlations and may provide additional data for the diagnostic performance of SPECTRALIS OCT.