title: The blue arc entoptic phenomenon in glaucoma (an American ophthalmological thesis).
abstract: OBJECTIVE
  To determine whether the blue arc entoptic phenomenon, a positive visual response originating from the retina with a shape that conforms to the topology of the nerve fiber layer, is depressed in glaucoma.
  
  
  METHODS
  We recruited a cross-sectional, nonconsecutive sample of 202 patients from a single institution in a prospective manner. Subjects underwent full ophthalmic examination, including standard automated perimetry (Humphrey Visual Field 24-2) or frequency doubling technology (Screening C 20-5) perimetry. Eligible patients viewed computer-generated stimuli under conditions chosen to optimize perception of the blue arcs. Unmasked testers instructed patients to report whether they were able to perceive blue arcs but did not reveal what response was expected. We created multivariable logistic regression models to ascertain the demographic and clinical parameters associated with perceiving the blue arcs.
  
  
  RESULTS
  In multivariable analyses, each 0.1 unit increase in cup-disc ratio was associated with 36% reduced likelihood of perceiving the blue arcs (odds ratio [OR] = 0.66 [95% confidence interval (CI): 0.53-0.83], P<.001). A smaller mean defect was associated with an increased likelihood of perceiving the blue arcs (OR=1.79 [95% CI: 1.40-2.28]); P<.001), while larger pattern standard deviation (OR=0.72 [95% CI: 0.57-0.91]; P=.005) and abnormal glaucoma hemifield test (OR=0.25 [0.10-0.65]; P=.006) were associated with a reduced likelihood of perceiving them. Older age and media opacity were also associated with an inability to perceive the blue arcs.
  
  
  CONCLUSIONS
  In this study, the inability to perceive the blue arcs correlated with structural and functional features associated with glaucoma, although older age and media opacity were also predictors of this entoptic response.
authors.affiliation: Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, and Department of Ophthalmology, Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts (Dr Pasquale), and Valley Eye Physicians and Surgeons, Ayer, Massachusetts (Dr Brusie).
authors.forename: Louis R
authors.initials: LR
authors.lastname: Pasquale
authors.forename: Steven
authors.initials: S
authors.lastname: Brusie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010775:Photic Stimulation / Q000379:methods; D011446:Prospective Studies; D058609:Visual Field Tests / Q000379:methods*; D014796:Visual Perception / Q000502:physiology*