Both pseudopapilledema and true papilledema have the appearance of an elevated optic disc, but only true papilledema is an urgent, sight-threatening condition. So, it’s vital to distinguish between the conditions as swiftly and accurately as possible.
Researchers have been seeking a technique or technology to give clinicians that easy assessment. Conventional OCT images of the optic nerve often fail to detect mild papilledema. However, researchers are now saying that clinicians can use OCT volumetric data to calculate additional parameters describing peripapillary tissue thickness, neuroretinal rim thickness and optic nerve head position—all of which can provide valuable measures for differentiating mild papilledema from pseudopapilledema.
The investigators used OCT optic nerve head volume scans from 21 papilledema patients (15 of which were mild papilledema), 27 pseudopapilledema and 42 control subjects. The team exported the raw scan data and calculated the total retinal thickness within Bruch’s membrane opening (BMO) plus retinal nerve fiber layer (RNFL) thickness and total retinal thickness. The results show that the custom RNFL thickness measurements were better able to distinguish mild papilledema from pseudopapilledema than total retinal thickness or BMO height. Ten mild papilledema patients demonstrated at least one elevated custom parameter.
“The pathophysiology of papilledema involves swelling of retinal ganglion cell axons, due to axoplasmic flow stasis,” the report explains. Since that edema likely stems from the prelaminar region and optic nerve head before affecting the peripapillary retina, quantifying OCT parameters at or near these regions should enhance the ability to detect early or mild papilledema, the investigators state. The results of this study support that hypothesis.
|Pardon L, Cheng H, Tang R. Custom optical coherence tomography parameters for distinguishing papilledema from pseudopapilledema. Optom Vis Sci. July 16, 2019. [Epub ahead of print].|