title: The effect of phenylephrine and cyclopentolate on objective wavefront measurements.
abstract: OBJECTIVE
  To investigate the impact of phenylephrine and cyclopentolate on wavefront refraction and fourth order spherical aberration C12.
  
  
  METHODS
  This cohort study comprised 151 eyes with sphere up to -10.00 diopters (D) and cylinder -3.75 D. Aberrometry was performed using the ALLEGRO WAVE (WaveLight Laser Technologies AG, Erlangen, Germany) after instillation of phenylephrine 5% yielding objective phenylephrine refraction in accommodated steady-state, as well as after cyclopentolate 0.5% providing objective cyclopentolate refraction in non-accommodated state. Accommodation target fogging was turned off. Wavefront aberrations were expressed by Zernike expansion up to the sixth order, and paraxial curvature matching with Taylor series was used to calculate objective wavefront sphere.
  
  
  RESULTS
  Objective wavefront sphere was not influenced by pupil size. Eyes showed substantial accommodation after phenylephrine with a myopic shift of -0.66 D comparing objective to subjective manifest sphere (r=0.942, P<.001). Cycloplegic eyes behaved like a model eye, with a difference of -0.08 D between objective and subjective cycloplegic sphere (r=0.976, P<.001). C12 increased ten-fold from 4.0- to 7.0-mm pupil size, keeping the same sign. Comparing cyclopentolate with phenylephrine, the sign of C12 changed in a positive direction by an average +0.124 +/- 0.109 microm (range: -0.052 to +0.632 microm) at 7.0 mm, whereas the total higher order aberrations changed very little. A good correlation was found between C12 and the change in objective wavefront sphere between cyclopentolate and phenylephrine (r=0.75, P<.001).
  
  
  CONCLUSIONS
  Fogging of the accommodation target should be used for wavefront measurements. Weaker cycloplegic agents, such as tropicamide, may be used to ensure relaxed but not completely paralyzed accommodation, which would yield "manifest" aberration values close to the natural resting state.
authors.affiliation: Milos Clinic Eye Hospital, Belgrade, Serbia and Montenegro. visioncare@mac.com
authors.forename: Mirko R
authors.initials: MR
authors.lastname: Jankov
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Iseli
authors.forename: Michael
authors.initials: M
authors.lastname: Bueeler
authors.forename: Paulo
authors.initials: P
authors.lastname: Schor
authors.forename: Theo
authors.initials: T
authors.lastname: Seiler
authors.forename: Michael
authors.initials: M
authors.lastname: Mrochen
mesh_terms: D000065:Accommodation, Ocular / Q000187:drug effects / Q000502:physiology*; D000328:Adult; D003519:Cyclopentolate / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009184:Mydriatics / Q000008:administration & dosage; D009216:Myopia / Q000175:diagnosis* / Q000503:physiopathology; D009883:Ophthalmic Solutions; D010656:Phenylephrine / Q000008:administration & dosage; D012029:Refraction, Ocular / Q000187:drug effects*; D012189:Retrospective Studies; D014792:Visual Acuity
chemical_list: D009184:Mydriatics; D009883:Ophthalmic Solutions; D010656:Phenylephrine; D003519:Cyclopentolate