title: Changes of ocular higher order aberration in on- and off-eye of rigid gas permeable contact lenses.
abstract: OBJECTIVE
  To investigate ocular higher order aberration (HOA) changes caused by rigid gas permeable (RGP) contact lens (CL) wear.
  
  
  METHODS
  Twenty-two eyes of 22 myopic patients and 14 eyes of 14 keratoconic patients who were fitted with an RGP CL were enrolled to examine ocular HOAs using a Hartmann-Shack wavefront sensor before and after RGP wear. Root mean square (RMS) values and Zernike coefficients in RGP-on and RGP-off eyes were compared for both myopic and keratoconic eyes, or between patient groups divided according to their prefitted total HOA value (RMS<0.33 microm or>or=0.33 microm in myopic eyes and RMS<0.46 microm or>or=0.46 microm in keratoconic eyes). All HOA values were recomputed for a 4-mm pupil for comparison purposes.
  
  
  RESULTS
  In keratoconic eyes, RGP CL changed the direction of vertical coma from -0.185 to 0.134 microm (p=0.024). In the low HOA myopic group, total HOA increased from 0.23 to 0.35 microm (p=0.006) by RGP CL wear, mainly due to increased coma aberration from 0.0951 to 0.2146 microm (p=0.006). The direction of vertical coma changed from the inferior to superior cornea in the low HOA group (p=0.020). In the high HOA keratoconic group, total HOA decreased from 0.54 to 0.36 microm (p=0.049), and the direction of the vertical coma changed from the inferior to superior cornea (p=0.049).
  
  
  CONCLUSIONS
  RGP CL wear may enhance or reduce HOA based on original existing ocular aberration mainly through directional changes in vertical coma.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, and Seoul Artificial Eye Center, Seoul National University Hospital Clinical Research Institute, Seoul, South Korea.
authors.forename: Jin
authors.initials: J
authors.lastname: Choi
authors.forename: Won Ryang
authors.initials: WR
authors.lastname: Wee
authors.forename: Jin Hak
authors.initials: JH
authors.lastname: Lee
authors.forename: Mee Kum
authors.initials: MK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D003262:Contact Lenses, Extended-Wear; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology* / Q000628:therapy; D008027:Light; D009216:Myopia / Q000503:physiopathology* / Q000628:therapy; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies