Causes of papilledema can be life-threatening; however, distinguishing papilledema from pseudopapilledema is often challenging. The conventional optical coherence tomography (OCT) scan for assessing the optic nerve often fails to detect mild papilledema. Our study suggests that parameters derived from volumetric OCT scans can provide additional useful information for detecting papilledema.
Optical coherence tomography analysis of the optic nerve commonly measures retinal nerve fiber layer thickness (RNFLT) along a 1.73-mm-radius scan path. This conventional scan, however, often fails to detect mild papilledema. The purpose of this study was to evaluate additional OCT-derived measures of the optic nerve head (ONH) and peripapillary retina for differentiating papilledema (all grades and mild) from pseudopapilledema.
Cirrus OCT ONH volume scans were acquired from 21 papilledema (15 mild papilledema), 27 pseudopapilledema, and 42 control subjects. Raw scan data were exported, and total retinal thickness within Bruch’s membrane opening (BMO) plus RNFLT and total retinal thickness at the following eccentricities were calculated using custom algorithms: BMO to 250, 250 to 500, 500 to 1000, and 1000 to 1500 μm. Minimum rim width was calculated, and BMO height was measured from a 4-mm Bruch’s membrane reference plane centered on the BMO.
Retinal nerve fiber layer thickness from BMO to 250 μm, minimum rim width, and BMO height had significantly greater areas under the receiver operating characteristic curve than did conventional RNFLT for differentiating mild papilledema from pseudopapilledema (P < .0001) and greater sensitivities at 95% specificity. Using cutoff values at 95% specificity, custom parameters detected 10 mild papilledema patients, and conventional RNFLT detected only 1. Bruch’s membrane opening heights above the reference plane were observed in papilledema only, although many papilledema cases had a neutral or negative BMO height.
Using OCT volumetric data, additional parameters describing peripapillary tissue thickness, neuroretinal rim thickness, and ONH position can be calculated and provide valuable measures for differentiating mild papilledema from pseudopapilledema.
1College of Optometry, University of Houston, Houston, Texas
Supplemental Digital Content: Appendix Table A1, available at http://links.lww.com/OPX/A406. Conventional retinal nerve fiber layer thickness, custom retinal nerve fiber layer thickness, and custom total retinal thickness values for control, papilledema, and pseudopapilledema eyes. Papilledema and pseudopapilledema eyes are described as “better” or “worse” depending on which eye had a thicker conventional retinal nerve fiber layer (worse = thicker). In the present study, better papilledema eyes were compared with worse pseudopapilledema eyes to make the two groups more difficult to differentiate. Values for both eyes are included here to provide a more complete clinical picture.
Appendix Table A2, available at http://links.lww.com/OPX/A406. Minimum rim width and Bruch’s membrane opening height values for control, papilledema, and pseudopapilledema eyes. Eyes described as worse have a thicker conventional retinal nerve fiber layer. Values for both eyes of papilledema and pseudopapilledema subjects are included to provide a more complete clinical picture.
Submitted: June 7, 2018
Accepted: May 4, 2019
Funding/Support: National Institutes of Health (T32 EY07024; to LPP) and National Institutes of Health (P30 EY007551; to LJF).
Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest.
Author Contributions: Conceptualization: LPP, HC, RAT, LJF, NBP; Data Curation: LPP, RS; Formal Analysis: LPP, HC; Funding Acquisition: LJF; Investigation: LPP, RAT; Methodology: LPP, HC, NBP; Project Administration: LJF; Resources: HC, RAT, RS, LJF, NBP; Software: LPP, NBP; Supervision: HC, LJF, NBP; Validation: LPP, HC, LJF, NBP; Visualization: LPP; Writing – Original Draft: LPP; Writing – Review & Editing: LPP, HC, RAT, RS, LJF, NBP.
Supplemental Digital Content: Direct URL links are provided within the text.
Online date: July 17, 2019