title: Anterior and posterior corneal curvature: normal values in healthy Iranian population obtained with the Orbscan II.
abstract: The objective of study was to determine the normative values of anterior and posterior best fit sphere (A-BFS and P-BFS) measured with Orbscan II Topography System. In this cross-sectional study, patients (age range: 18-40 years) referred to the Khatam Eye Hospital (Mashhad, Iran) were put in an observational cross-sectional study. The A-BFS and P-BFS were measured with the Orbscan II. The differences between genders, between right and left eyes, and age-related changes were evaluated. A total of 977 healthy participants consisted of 614 female and 363 male subjects aged 18-35 years participated. The average A-BFS in our study population was recorded as 43.060 ± 1.541 D (median: 43.00 D, mode: 43.10 D, range: 38.80-55.80 D). The average P-BFS in our study population was recorded as 52.702 ± 2.190 D (median: 52.60 D, mode: 53.10 D range: 46.9-62.20 D). The A-BFS and P-BFS were respectively 42.753 ± 1.629 and 52.327 ± 2.376 D in males and 43.242 ± 1.457 and 52.924 ± 2.041 D in females, which were statistically different between the genders (P < 0.001). However, A-BFS and P-BFS were not statistically different between right and left eyes (P = 0.649 and P = 0.688 respectively). In addition, A-BFS and P-BFS were not correlated with the age (r = 0.038, P = 0.096 and r = -0.142, P = 0.178 respectively). Considering 95 % confidence interval, A-BFS less than 43.13 D and greater than 42.99 D and P-BFS less than 52.80 D and greater than 52.60 D would be considered abnormal. Detailed description and analysis of A-BFS and P-BFS with Orbscan demonstrated that the obtained average value of BFS were higher in male than female and did not change with increasing age.
authors.affiliation: Cornea Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Gharaee
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Abrishami
authors.forename: Mostafa
authors.initials: M
authors.lastname: Abrishami
authors.forename: Seyyed Mohammad
authors.initials: SM
authors.lastname: Mirhosseini
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Mehrabi Bahar
authors.forename: Pardis
authors.initials: P
authors.lastname: Eghbali
mesh_terms: D000328:Adult; D000869:Anterior Eye Segment / Q000033:anatomy & histology*; D044466:Asian People; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000379:methods*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007492:Iran; D008297:Male; D057972:Posterior Eye Segment / Q000033:anatomy & histology*; D012016:Reference Values; D055815:Young Adult