title: Comparative regional pupillography as a noninvasive biosensor screening method for diabetic retinopathy.
abstract: OBJECTIVE
  We describe infrared regional pupillometry as an objective comparative assessment of midperipheral to central retinal sensitivity and to correlate with midperipheral retinal ischemia in diabetic subjects.
  
  
  METHODS
  We tested 12 normal and 17 diabetic subjects using bilateral infrared pupillometry. The diabetic cohort included seven subjects without, five with mild, three with moderate, and two with severe non-proliferative diabetic retinopathy (NPDR). Central and annular stimuli of varying intensity were presented to one eye, and pupillary amplitude and constriction velocity were measured from both eyes. Light stimulus of increasing intensity was presented as 20 consecutive trials (stimulus duration of 300 ms with 3000 ms intervals). The ratio of central to peripheral responses (Q values) was calculated for each stimulus configuration. Average responses with respect to the stimulus strength were regressed with Gompertz sigmoid function.
  
  
  RESULTS
  Control and moderate/severe NPDR cases comparison showed statistically significant differences in amplitude (Q(A)) and constriction velocity (Q(CV)) (Wilcoxon rank sum test P = 0.002, respectively). Age difference for these groups was not statistically significant (Wilcoxon rank sum test P = 0.15). The comparison of control and diabetic subjects without NPDR/mild NPDR was statistically significant for Q(A) and Q(CV) (Wilcoxon rank sum test P = 0.0002 and P = 0.001, respectively). Q(A) and Q(CV) differences were statistically significant between moderate/severe NPDR cases and subjects without or mild NPDR cases (Wilcoxon rank sum test P = 0.013).
  
  
  CONCLUSIONS
  Q(A) and Q(CV) values correlated highly with the severity of diabetic retinopathy, but not with the duration of diabetes.
authors.affiliation: Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Maria Carolina
authors.initials: MC
authors.lastname: Ortube
authors.forename: Alexander
authors.initials: A
authors.lastname: Kiderman
authors.forename: Yakov
authors.initials: Y
authors.lastname: Eydelman
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Nelson
authors.initials: N
authors.lastname: Aguilar
authors.forename: Steven
authors.initials: S
authors.lastname: Nusinowitz
authors.forename: Michael B
authors.initials: MB
authors.lastname: Gorin
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology; D015374:Biosensing Techniques; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D005451:Fluorescein Angiography; D006801:Humans; D007259:Infrared Rays; D008027:Light; D008297:Male; D008875:Middle Aged; D011680:Pupil / Q000528:radiation effects*; D012025:Reflex, Pupillary