title: The influence of corneoscleral topography on soft contact lens fit.
abstract: OBJECTIVE
  To evaluate the influence of peripheral ocular topography, as evaluated by optical coherence tomography (OCT), compared with traditional measures of corneal profile using keratometry and videokeratoscopy, on soft contact lens fit.
  
  
  METHODS
  Ocular surface topography was analyzed in 50 subjects aged 22.8 years (SD ±5.0) using videokeratoscopy (central keratometry, corneal height, and shape factor) and OCT to give both full sagittal cross-sections of the cornea and cross-sections of the corneoscleral junctions. Corneoscleral junction angle, corneal diameter, corneal sagittal height, and scleral radius were analyzed from the images. Horizontal visible iris diameter and vertical palpebral aperture were analyzed from digital slit lamp images. Lens fit was graded after 30 minutes wear of a -2.50 D commercially available standard hydrogel (etafilcon A, modulus 0.30 MPa) and silicone hydrogel (galyfilcon A, 0.43 MPa) design of similar geometries (8.30-mm base curve, 14.0-mm diameter).
  
  
  RESULTS
  The mean horizontal corneal diameter was 13.39 mm (SD ±0.44). In many cases, there was a tangential transition at the corneoscleral junction. The corneoscleral shape profile analyzed from cross-sectional OCT images contributed significantly (P < 0.001) to the prediction of soft contact lens fit compared with keratometry and videokeratoscopy, accounting for up to 24% of the variance in lens movement. The fit of the stiffer material silicone hydrogel lens was better able to be predicted and was more varied than the hydrogel contact lens.
  
  
  CONCLUSIONS
  The extra peripheral corneoscleral data gained from OCT characterization of ocular surface architecture provide valuable insight into soft contact lens fit dynamics.
authors.affiliation: Visioncare Research Ltd., Craven House, West Street, Farnham, Surrey GU97EN, UK. l.hall@visioncare.co.uk
authors.forename: Lee A
authors.initials: LA
authors.lastname: Hall
authors.forename: Graeme
authors.initials: G
authors.lastname: Young
authors.forename: James S
authors.initials: JS
authors.lastname: Wolffsohn
authors.forename: Colleen
authors.initials: C
authors.lastname: Riley
mesh_terms: D000293:Adolescent; D000328:Adult; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000473:pathology / Q000503:physiopathology / Q000534:rehabilitation*; D011446:Prospective Studies; D017755:Prosthesis Fitting; D012029:Refraction, Ocular; D012590:Sclera / Q000473:pathology*; D041623:Tomography, Optical Coherence; D055815:Young Adult