Analysis of the neuroretinal rim (NRR), retinal nerve fiber layer (RNFL), and the ganglion cell complex (GCC) is performed by comparing the patient to a large database of “normals,” who serve as controls. Each OCT unit houses data collected from clinical research for varying age groups. It can then compare your patient to the appropriately age-matched control group. This is important, as NRR, RNFL and GCC tissue normally decline with age. For added specificity, when interpreting OCT data quantitatively it is important to differentiate age-related tissue loss from true glaucomatous damage.
It is possible to add racial databases and even refractive-based databases to the OCT unit. However, practically speaking, age-matched controls without the addition of race/refraction have been well studied in many clinical trials and are thus the current standard of care.