title: Factors affecting corneoscleral topography.
abstract: OBJECTIVE
  To evaluate factors affecting corneoscleral profile (CSP) using anterior segment optical coherence tomography (AS-OCT) in combination with conventional videokeratoscopy.
  
  
  METHODS
  OCT DATA WERE COLLECTED FROM 204 SUBJECTS OF MEAN AGE 34.9 YEARS (SD: ±15.2 years, range 18-65) using the Zeiss Visante AS-OCT and Medmont M300 corneal topographer. Measurements of corneal diameter (CD), corneal sagittal height (CS), iris diameter (ID), corneoscleral junction angle (CSJ), and scleral radius (SR) were extracted from multiple OCT images. Horizontal visible iris diameter (HVID) and vertical palpebral aperture (PA) were measured using a slit lamp graticule. Subject body height was also measured. Associations were then sought between CSP variables and age, height, ethnicity, sex, and refractive error.
  
  
  RESULTS
  Significant correlations were found between age and ocular topography variables of HVID, PA, CSJ, SR, and ID (P < 0.0001), while height correlated with HVID, CD, and ID, and power vector terms with vertical plane keratometry, CD, and CS. Significant differences were noted between ethnicities with respect to CD (P = 0.0046), horizontal and vertical CS (P = 0.0068 and P = 0.0095), and horizontal ID (P = 0.0010). The same variables, with the exception of vertical CS, also varied with sex; horizontal CD (P = 0.0018), horizontal CS (P = 0.0018), and ID (P = 0.0012). Age accounted for the greatest variance in topography variables (36%).
  
  
  CONCLUSIONS
  Age is the main factor influencing CSP; this should be taken into consideration in contact lens design, IOL selection, and in the optimization of surgical procedures. Ocular topography also varied with height, sex, ethnicity, and refractive error.
authors.affiliation: Visioncare Research Ltd., Farnham, United Kingdom. l.hall@visioncare.co.uk
authors.forename: Lee A
authors.initials: LA
authors.lastname: Hall
authors.forename: Chris
authors.initials: C
authors.lastname: Hunt
authors.forename: Graeme
authors.initials: G
authors.lastname: Young
authors.forename: James
authors.initials: J
authors.lastname: Wolffsohn
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000869:Anterior Eye Segment / Q000033:anatomy & histology; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000379:methods* / Q000592:standards*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000473:pathology; D015203:Reproducibility of Results; D012590:Sclera / Q000033:anatomy & histology*; D012737:Sex Factors; D041623:Tomography, Optical Coherence / Q000379:methods* / Q000592:standards*; D055815:Young Adult
keywords: OCT; corneal topography; corneoscleral profile