title: Characterization of field loss based on microperimetry is predictive of face recognition difficulties.
abstract: OBJECTIVE
  To determine how visual field loss as assessed by microperimetry is correlated with deficits in face recognition.
  
  
  METHODS
  Twelve patients (age range, 26-70 years) with impaired visual sensitivity in the central visual field caused by a variety of pathologies and 12 normally sighted controls (control subject [CS] group; age range, 20-68 years) performed a face recognition task for blurred and unblurred faces. For patients, we assessed central visual field loss using microperimetry, fixation stability, Pelli-Robson contrast sensitivity, and letter acuity.
  
  
  RESULTS
  Patients were divided into two groups by microperimetry: a low vision (LV) group (n = 8) had impaired sensitivity at the anatomical fovea and/or poor fixation stability, whereas a low vision that excluded the fovea (LV:F) group (n = 4) was characterized by at least some residual foveal sensitivity but insensitivity in other retinal regions. The LV group performed worse than the other groups at all blur levels, whereas the performance of the LV:F group was not credibly different from that of the CS group. The performance of the CS and LV:F groups deteriorated as blur increased, whereas the LV group showed consistently poor performance regardless of blur. Visual acuity and fixation stability were correlated with face recognition performance.
  
  
  CONCLUSIONS
  Persons diagnosed as having disease affecting the central visual field can recognize faces as well as persons with no visual disease provided that they have residual sensitivity in the anatomical fovea and show stable fixation patterns. Performance in this task is limited by the upper resolution of nonfoveal vision or image blur, whichever is worse.
authors.affiliation: Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Thomas S A
authors.initials: TS
authors.lastname: Wallis
authors.forename: Christopher Patrick
authors.initials: CP
authors.lastname: Taylor
authors.forename: Jennifer
authors.initials: J
authors.lastname: Wallis
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Jackson
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bex
mesh_terms: D000328:Adult; D000368:Aged; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D020238:Prosopagnosia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012607:Scotoma / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult
keywords: Bayesian inference; central vision loss; face recognition; low vision; perimetry