title: Digital pupillometry and centroid shift changes after cataract surgery.
abstract: OBJECTIVE
  To compare postoperative changes in apparent photopic and mesopic pupil size and centration in relation to cornea reflection landmarks after cataract surgery.
  
  
  METHODS
  LaserVision.gr Clinical and Research Eye Institute, Athens, Greece.
  
  
  METHODS
  Prospective consecutive case study.
  
  
  METHODS
  Pupils were imaged for pupil size and corneal vertex location before and 1-month after cataract surgery. Digital analysis of pupil images was used to determine the Cartesian coordinates (nasal-temporal, horizontal axis, superior-inferior, vertical axis) of the first Purkinje reflection point (approximating the corneal intersection of the visual axis [corneal vertex]) to the pupil geometric center (approximating the corneal intersection of the line of sight [corneal apex]). Pupil size changes were measured, and the correlation between vertex-to-apex shift changes and postoperative pupil centroid shift was evaluated.
  
  
  RESULTS
  The study evaluated 40 eyes. The pupil size (diameter) change corresponded to a relative reduction of -9.8% for photopic pupils and -9.1% for mesopic pupils; the difference was statistically significant (P = .045 and P = .011, respectively). Also, there was a reduction in the centroid shift (all eyes) from a mean of 0.12 mm preoperatively to 0.05 mm postoperatively as a result of the postoperative minus temporal horizontal difference between the corneal vertex and the apex.
  
  
  CONCLUSIONS
  Cataract extraction surgery appears to affect pupil size and centration. Specifically, a smaller pupil and less temporal shift were recorded. These data may have clinical relevance in targeted intraoperative intraocular lens centration.
  
  
  BACKGROUND
  Dr. Kanellopoulos is a consultant to Alcon Surgical, Inc., Wavelight Laser Technologie AG, Allergan, Avedro, Inc., and i-Optics Corp. No author has a financial or proprietary interest in any material or method mentioned.
authors: From Laservision.gr Clinical and Research Eye Institute (Kanellopoulos, Asimellis, Georgiadou), Athens, Greece, and New York University School of Medicine (Kanellopoulos), New York, New York, USA. Electronic address: ajk@brilliantvision.com.
authors: Anastasios John
authors: AJ
authors: Kanellopoulos
authors: From Laservision.gr Clinical and Research Eye Institute (Kanellopoulos, Asimellis, Georgiadou), Athens, Greece, and New York University School of Medicine (Kanellopoulos), New York, New York, USA.
authors: George
authors: G
authors: Asimellis
authors: From Laservision.gr Clinical and Research Eye Institute (Kanellopoulos, Asimellis, Georgiadou), Athens, Greece, and New York University School of Medicine (Kanellopoulos), New York, New York, USA.
authors: Stella
authors: S
authors: Georgiadou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D055253:Color Vision / Q000502:physiology; D003315:Cornea / Q000033:anatomy & histology; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D055255:Mesopic Vision / Q000502:physiology; D008875:Middle Aged; D015878:Mydriasis / Q000503:physiopathology; D018918:Phacoemulsification; D011446:Prospective Studies; D011680:Pupil / Q000502:physiology*