title: Influence of refractive error on pupillary dynamics in the normal and mild traumatic brain injury (mTBI) populations.
abstract: OBJECTIVE
  There have been several studies investigating static, baseline pupil diameter in visually-normal individuals across refractive error. However, none have assessed the dynamic pupillary light reflex (PLR). In the present study, both static and dynamic pupillary parameters of the PLR were assessed in both the visually-normal (VN) and the mild traumatic brain injury (mTBI) populations and compared as a function of refractive error.
  
  
  METHODS
  The VN population comprised 40 adults (22-56 years of age), while the mTBI population comprised 32 adults (21-60 years of age) over a range of refractive errors (-9.00D to +1.25D). Seven pupillary parameters (baseline static diameter, latency, amplitude, and peak and average constriction and dilation velocities) were assessed and compared under four white-light stimulus conditions (dim pulse, dim step, bright pulse, and bright step). The Neuroptics, infrared, DP-2000 binocular pupillometer (30Hz sampling rate; 0.05mm resolution) was used in the monocular (right eye) stimulation mode.
  
  
  RESULTS
  For the majority of pupillary parameters and stimulus conditions, a Gaussian distribution best fit the data, with the apex centered in the low myopic range (-2.3 to -4.9D). Responsivity was reduced to either side of the apex.
  
  
  CONCLUSIONS
  Over a range of dynamic and static pupillary parameters, the PLR was influenced by refractive error in both populations. In cases of high refractive error, the PLR parameters may need to be compensated for this factor for proper categorization and diagnosis.
authors.affiliation: SUNY College of Optometry, Department of Biological and Vision Sciences, 33 West 42(nd) Street, New York, NY 10036, USA.
authors.forename: James Q
authors.initials: JQ
authors.lastname: Truong
authors.affiliation: SUNY College of Optometry, Department of Biological and Vision Sciences, 33 West 42(nd) Street, New York, NY 10036, USA. Electronic address: njoshi@sunyopt.edu.
authors.forename: Nabin R
authors.initials: NR
authors.lastname: Joshi
authors.affiliation: SUNY College of Optometry, Department of Biological and Vision Sciences, 33 West 42(nd) Street, New York, NY 10036, USA.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ciuffreda
mesh_terms: D000328:Adult; D000070642:Brain Injuries, Traumatic / Q000503:physiopathology*; D064368:Healthy Volunteers; D006801:Humans; D008027:Light; D008875:Middle Aged; D010775:Photic Stimulation; D012025:Reflex, Pupillary / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*; D055815:Young Adult
keywords: Error refractivo; Infrared pupillometry; Lesión cerebral traumática leve (mTBI); Mild traumatic brain injury (mTBI); Miopía; Myopia; Pupil light reflex (PLR); Pupilometría por infrarrojos; Reflejo pupilar a la luz (RPL); Refractive error