title: Improved fixation quality provided by a Bessel beacon in an adaptive optics system.
abstract: OBJECTIVE
  We investigate whether a structured probe beam that creates the beacon for use in a retinal imaging adaptive optics system can provide useful side effects. In particular we investigate whether a Bessel beam that is seen by the subject as a set of concentric rings has a dampening effect on fixation variations of the subject under observation. This calming effect would allow longer periods of observation, particularly for patients with abnormal fixation.
  
  
  METHODS
  An experimental adaptive optics system developed for retinal imaging is used to monitor the fluctuations in aberrations for artificial and human subjects. The probe beam is alternated between a traditional beacon and one provided by a Bessel beam created by SLM.
  
  
  RESULTS
  Time-frequency analysis is used to indicate the differences in power and time variation during fixation depending on whether the Bessel beam or the traditional beacon is employed. Comparison is made with the response for an artificial eye to discount systemic variations.
  
  
  CONCLUSIONS
  Significant evidence is accrued to indicate the reduced fluctuations in fixation when the Bessel beam is employed to create the beacon.
authors.affiliation: School of Engineering and Information Technology, The University of New South Wales, Australian Defence Force Academy, Canberra, Australia. a.lambert@adfa.edu.au
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lambert
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Daly
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Dainty
mesh_terms: D000328:Adult; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D008953:Models, Anatomic; D009887:Ophthalmoscopy / Q000379:methods*; D055095:Optics and Photonics / Q000379:methods*; D012160:Retina / Q000033:anatomy & histology