title: Comparison of higher order aberrations in patients with various refractive errors.
abstract: OBJECTIVE
  To compare the mean root mean square (RMS) of total higher order aberrations (HOAs), coma and spherical aberrations in individuals with myopia, hypermetropia and myopic astigmatism.
  
  
  METHODS
  This prospective analytical study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from Jan 2014 to Dec 2014. Two hundred eyes of 121 patients with age ranging from 18-40 years were included in the study. Patients were divided into 4 group namely Low myopia, High myopia, Astigmatism and Hypermetropia on the basis of refractive error. Included were the patients who had refractive error more than ± 0.5D and best corrected visual acuity (BCVA) of 0.00 or better. Patients who had history of surgery and / or eye disease were excluded from the study. Visual acuity (VA), Spherical equivalent (SE) of refractive error, RMS value of total HOAs, coma and spherical aberrations were evaluated. HOAs were measured with aberrometer (Wavelight analyzer version 1073) at 6 mm pupil size.
  
  
  RESULTS
  Age of the patients ranged from 18 years to 40 years with mean age of 29.10±10.6 years. Seventy one (35.5%) were males and 129 (64.5%) were female. Mean RMS value of HOAs, coma and spherical aberrations was calculated in all four groups. RMS of total HOAs and spherical aberrations in hypermetropia was 0.96±0.96 and 0.30±0.42 respectively and it was higher than other three groups.
  
  
  CONCLUSIONS
  In overall comparison the mean RMS of total HOAs and spherical aberrations was significantly increased in hypermetropia group and there was a statistically significant negative correlation of SE of hypermetropia with RMS of total HOAs and spherical aberration.
authors.affiliation: Dr. Muhammad Saim Khan, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Muhammad Saim
authors.initials: MS
authors.lastname: Khan
authors.affiliation: Dr. Sadia Humayun, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Sadia
authors.initials: S
authors.lastname: Humayun
authors.affiliation: Dr. Aisha Fawad, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Aisha
authors.initials: A
authors.lastname: Fawad
authors.affiliation: Prof. Dr. Mazhar Ishaq, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Mazhar
authors.initials: M
authors.lastname: Ishaq
authors.affiliation: Miss. Sabahat Arzoo, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Sabahat
authors.initials: S
authors.lastname: Arzoo
authors.affiliation: Dr. Fawad Mashhadi, Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan.
authors.forename: Fawad
authors.initials: F
authors.lastname: Mashhadi
keywords: Aberrometery; Higher Order Aberration; Refractive Error; Visual acuity