title: Spatial Interpolation Enables Normative Data Comparison in Gaze-Contingent Microperimetry.
abstract: OBJECTIVE
  To demonstrate methods that enable visual field sensitivities to be compared with normative data without restriction to a fixed test pattern.
  
  
  METHODS
  Healthy participants (n = 60, age 19-50) undertook microperimetry (MAIA-2) using 237 spatially dense locations up to 13° eccentricity. Surfaces were fit to the mean, variance, and 5th percentile sensitivities. Goodness-of-fit was assessed by refitting the surfaces 1000 times to the dataset and comparing estimated and measured sensitivities at 50 randomly excluded locations. A leave-one-out method was used to compare individual data with the 5th percentile surface. We also considered cases with unknown fovea location by adding error sampled from the distribution of relative fovea-optic disc positions to the test locations and comparing shifted data to the fixed surface.
  
  
  RESULTS
  Root mean square (RMS) difference between estimated and measured sensitivities were less than 0.5 dB and less than 1.0 dB for the mean and 5th percentile surfaces, respectively. Root mean square differences were greater for the variance surface, median 1.4 dB, range 0.8 to 2.7 dB. Across all participants 3.9% (interquartile range, 1.8-8.9%) of sensitivities fell beneath the 5th percentile surface, close to the expected 5%. Positional error added to the test grid altered the number of locations falling beneath the 5th percentile surface by less than 1.3% in 95% of participants.
  
  
  CONCLUSIONS
  Spatial interpolation of normative data enables comparison of sensitivity measurements from varied visual field locations. Conventional indices and probability maps familiar from standard automated perimetry can be produced. These methods may enhance the clinical use of microperimetry, especially in cases of nonfoveal fixation.
authors.affiliation: Visual Neuroscience Group, School of Psychology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Denniss
authors.affiliation: Visual Neuroscience Group, School of Psychology, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Astle
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology*; D015203:Reproducibility of Results; D012684:Sensory Thresholds / Q000502:physiology*; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult