TABLE 1.

Limitations of the mean RNFL thickness

No normative values for children younger than 18 years

No normative adjustments for high myopes

Adults with “normal” (5%–95% of controls) mean RNFL thickness may still have optic disc edema  Early or mild cases of papilledema (12).  Anatomical variants with thin baseline RNFL thickness (7)  Focal swelling (e.g., in NA-AION)  Chronic papilledema

Thickening of the RNFL (>95% of controls) without optic disc edema (pseudopapilledema)  Optic disc drusen especially in children (13,27,28)  Other disorders of the optic nerve head and retina: gliosis, myelinated nerve fibers, retinal edema, hyperopia, and epiretinal membranes (29)

Segmentation failures especially in severe papilledema (1,11,12,29–31)

Artifacts (29)  Low-signal strength ≤6  High myopia and high hyperopia  Decentration of the circular tomogram  Topographic variability of the RNFL bundles and thickness  Movement artifacts  Cyclotorsion  Peripapillary atrophy

NA-AION, nonarteritic anterior ischemic optic neuropathy; RNFL, retinal nerve fiber layer.