title: Differentiating optic disc edema from optic nerve head drusen on optical coherence tomography.
abstract: OBJECTIVE
  To assess optical coherence tomography in differentiating optic disc edema (ODE) due to papilledema and other optic neuropathies from optic nerve head drusen (ONHD).
  
  
  METHODS
  Optical coherence tomographic images from 60 subjects (20 with ODE, 20 with ONHD, and 20 control subjects) were assessed qualitatively and quantitatively. Qualitative criteria for ODE included an elevated optic nerve head with smooth internal contour and subretinal hyporeflective space (SHYPS) with recumbent "lazy V" pattern. Optic nerve head drusen displayed a "lumpy-bumpy" internal optic nerve contour and a rapid decline in SHYPS thickness. Quantitative comparisons included retinal nerve fiber layer and SHYPS thickness.
  
  
  RESULTS
  Optical coherence tomography differentiated ODE from ONHD qualitatively (sensitivity, 63%; specificity, 63%) and quantitatively (sensitivity, 80%; specificity, 90%). Respective differences in mean retinal nerve fiber layer thickness between ODE and ONHD were significant (P < .002) superiorly (206.8 vs 121.7 microm), nasally (176.3 vs 78.6 microm), inferiorly (247.2 vs 153.8 microm), and temporally (180.0 vs 85.5 microm). Respective differences in mean SHYPS thickness between ODE and ONHD were significant (P < .001) at radii of 0.75 mm (512.1 vs 274.4 microm), 1.5 mm (291.4 vs 103.0 microm), and 2.0 mm (145.5 vs 60.7 microm).
  
  
  CONCLUSIONS
  Optical coherence tomography can differentiate ODE from ONHD, particularly when the nasal retinal nerve fiber layer and SHYPS thickness at the 2.0-mm radius are greater than 86 microm and 127 microm, respectively.
authors.affiliation: Neuro-Ophthalmology Unit, Mason Eye Institute, University of Missouri-Columbia, Columbia, MO 65212, USA. johnsonln@health.missouri.edu
authors.forename: Lenworth N
authors.initials: LN
authors.lastname: Johnson
authors.forename: Meredith L
authors.initials: ML
authors.lastname: Diehl
authors.forename: Chuck W
authors.initials: CW
authors.lastname: Hamm
authors.forename: Drew N
authors.initials: DN
authors.lastname: Sommerville
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Petroski
mesh_terms: D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D009412:Nerve Fibers / Q000473:pathology; D015594:Optic Disk Drusen / Q000175:diagnosis*; D010211:Papilledema / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012165:Retinal Ganglion Cells / Q000473:pathology; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*