This study compared measurements of peripapillary retinal thickness from three-dimensional optical coherence tomography volume scans to traditional two-dimensional retinal nerve fiber layer thickness measurements for diagnosing primary open-angle glaucoma. The study found that certain retinal thickness parameters, such as measurements in the inferior quadrants, had diagnostic capabilities comparable or superior to retinal nerve fiber layer thickness measurements. Additionally, retinal thickness measurements exhibited a lower artifact rate compared to retinal nerve fiber layer measurements. The study concludes that assessment of peripapillary retinal thickness may provide a useful evaluation for glaucoma.