Evaluation of macular thickness and peripapillary retinal nerve fiber layer thickness for detection of early glaucoma using spectral domain optical coherence tomography.

PURPOSE

To evaluate the diagnostic ability of macular parameters and peripapillary retinal nerve fiber layer (RNFL) parameters for early glaucoma using spectral domain optical coherence tomography (SD-OCT).

MATERIALS AND METHODS

One eye from 32 early glaucoma patients (including preperimetric glaucoma) and 32 normal participants underwent macular scans and peripapillary RNFL scans with SD-OCT 3 times on the same day. The discrimination power of each parameter to detect early glaucoma was determined by areas under receiver operating characteristics curve (AROC) and sensitivity at fixed specificity. Correlation of OCT data with visual field defects was evaluated by linear regression analysis. Reproducibility was also evaluated.

RESULTS

Significant differences between early glaucoma and normal participants were found for all parameters except fovea in macular scans and in the superior and inferior quadrants, at 12, 3, 6, 7, 11 o'clock, and average RNFL thickness in RNFL scans. The best parameters based on AROC and sensitivity at a specificity of >90% were temporal outer macula thickness (AROC, 0.79; sensitivity, 63%) in macular parameters and inferior quadrant (AROC, 0.82; sensitivity, 53%) in RNFL parameters. The highest correlation with mean deviation was found in inferior inner macular volume (r=0.50, P<0.001). The mean intraclass correlation coefficient was 0.96 in macular scans and 0.84 in RNFL scans. Test-retest variability ranged from 2.3 to 10.1 μm in macular thickness, 0 to 0.06 mm in macular volume, and 5.8 to 18.9 μm in RNFL thickness.

CONCLUSION

For the diagnosis of early glaucoma by SD-OCT, macular parameters had high discriminating power and high reproducibility comparable with peripapillary RNFL parameters.