title: Progression of lower and higher-order aberrations: a longitudinal study.
abstract: BACKGROUND
  The aim of the present study was to investigate the effect of near-work on lower and higher-order aberrations, and its progression over a 9-month period during the school year.
  
  
  METHODS
  Data from 24 young-adult myopic eyes, and 24 non-myopic eyes were used in this investigation. The lower-order aberrations, coma, spherical aberration (SA), and total root mean square (RMS) of higher order aberrations (total HOA) were measured using an open-field iTrace aberrometer, at both the initial baseline evaluation, and then at the follow-up visits over a 9-month period. Pupil size of 4 mm was used for the aberration measurements.
  
  
  RESULTS
  The group mean (SD) of the subjects (mean age: 23.6 +/- 3.4 years) at the initial and follow-up visit was 0.47D (0.47D) and 0.31D (0.41D), in the non-myopes and -3.58D (2.08D) and -3.86D (2.14D) in the myopes, respectively. Significant increases in myopic refraction were observed. The group mean (SD) total HOA at the initial and final visit was 0.12 (0.08) and 0.11 (0.06) microns, in the non-myopes, and 0.15 (0.08) and 0.15 (0.08) microns, in the myopes, respectively. The group mean RMS of the coma at the initial and final visit was 0.06 (0.04) and 0.07 (0.05), in the non-myopes, and 0.08 (0.06) and 0.09 (0.06) microns, in the myopes, respectively. The group mean SA of the subjects at the initial and last visit was 0.04 (0.04) and 0.03 (0.03), in the non-myopes, and 0.04 (0.04) and 0.04 (0.04) microns, in the myopes, respectively.
  
  
  CONCLUSIONS
  There was a significant difference in myopic refraction, over the 9-month assessment period. However, no significant difference in total HOA, SA, and coma between the initial and follow-up visits in both the myopes and the non-myopes was observed.
authors.affiliation: College of Optometry Midwestern University, Glendale, AZ, 85308, USA. bvasud@midwestern.edu.
authors.forename: Balamurali
authors.initials: B
authors.lastname: Vasudevan
authors.affiliation: College of Optometry Midwestern University, Glendale, AZ, 85308, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Fisher
authors.affiliation: College of Optometry Midwestern University, Glendale, AZ, 85308, USA.
authors.forename: Barry
authors.initials: B
authors.lastname: Case
authors.affiliation: College of Optometry Midwestern University, Glendale, AZ, 85308, USA.
authors.forename: Phu
authors.initials: P
authors.lastname: Lam
authors.affiliation: College of Optometry Midwestern University, Glendale, AZ, 85308, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Wayman
mesh_terms: D057128:Aberrometry; D000328:Adult; D001251:Astigmatism / Q000175:diagnosis; D057108:Corneal Wavefront Aberration / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D009216:Myopia / Q000175:diagnosis* / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity; D055815:Young Adult