title: Facilitating Glaucoma Diagnosis With Intereye Retinal Nerve Fiber Layer Asymmetry Using Spectral-Domain Optical Coherence Tomography.
abstract: OBJECTIVE
  To test whether increased intereye retinal nerve fiber layer (RNFL) asymmetry may be indicative of glaucoma. To determine the best statistical methods and intereye RNFL cutoffs for differentiating between normal and glaucoma subjects to better alert clinicians to early glaucomatous damage.
  
  
  METHODS
  Sixty-six primary open-angle glaucoma (OAG) and 40 age-matched normal subjects had both eyes imaged at the Massachusetts Eye and Ear Infirmary with a commercially available spectral-domain optical coherence tomography (OCT) machine. Statistical methodologies were used to find cutoffs that achieved the best sensitivities and specificities for differentiating OAG from normal subjects.
  
  
  RESULTS
  Intereye RNFL asymmetry for global average, all quadrants, and all sectors was significantly greater in OAG than normal subjects. Intereye RNFL asymmetry for global average showed the greatest statistical difference (P<0.001) between OAG (23.64 ± 14.90 μm) and normal eyes (3.58 ± 3.96 μm), with 6.60 times greater asymmetry in OAG eyes. The inferior quadrant showed the second greatest difference, with 3.91 times greater asymmetry in OAG eyes. Using a statistically determined cutoff of 6.0 μm as abnormal, intereye RNFL asymmetry for global average achieved a sensitivity of 74.24% and specificity of 90% in differentiating between normal and OAG subjects, achieving a better combination of sensitivity and specificity than intereye RNFL asymmetry of any quadrant or sector.
  
  
  CONCLUSIONS
  Intereye RNFL asymmetry may be a useful clinical OCT measurement to provide quantitative assessment of early glaucomatous damage. Newly developed algorithms for intereye RNFL asymmetry may improve the ability to detect glaucoma.
authors.affiliation: *Department of Ophthalmology, Harvard Medical School, Glaucoma Service, Massachusetts Eye and Ear Infirmary, Boston, MA †Miller School of Medicine, University of Miami, Miami, FL.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Field
authors.forename: Tarek
authors.initials: T
authors.lastname: Alasil
authors.forename: Neda
authors.initials: N
authors.lastname: Baniasadi
authors.forename: Christian
authors.initials: C
authors.lastname: Que
authors.forename: Huseyin
authors.initials: H
authors.lastname: Simavli
authors.forename: Doaa
authors.initials: D
authors.lastname: Sobeih
authors.forename: David
authors.initials: D
authors.lastname: Sola-Del Valle
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Best
authors.forename: Teresa C
authors.initials: TC
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001699:Biometry; D003430:Cross-Sectional Studies; D005260:Female; D007839:Functional Laterality; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D064368:Healthy Volunteers; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods