title: Ocular biometry by computed tomography in different dog breeds.
abstract: OBJECTIVE
  To (i) correlate B-mode ocular ultrasound (US) and computed tomography (CT) (prospective pilot study), (ii) establish a reliable method to measure the normal canine eye using CT, (iii) establish a reference guide for some dog breeds, (iv) compare eye size between different breeds and breed groups, and (v) investigate the correlation between eye dimensions and body weight, gender, and skull type (retrospective study).
  
  
  METHODS
  B-mode US and CT were performed on ten sheep cadaveric eyes. CT biometry involved 100 adult pure-bred dogs with nonocular and nonorbital disease, representing eleven breeds. Eye length, width, and height were each measured in two of three planes (horizontal, sagittal, and equatorial).
  
  
  RESULTS
  B-mode US and CT measurements of sheep cadaveric eyes correlated well (0.70-0.71). The shape of the canine eye was found to be akin to an oblate spheroid (a flattened sphere). A reference guide was established for eleven breeds. Eyes of large breed dogs were significantly larger than those of medium and small breed dogs (P < 0.01), and eyes of medium breed dogs were significantly larger than those of small breed dogs (P < 0.01). Eye size correlated with body weight (0.74-0.82) but not gender or skull type.
  
  
  CONCLUSIONS
  Computed tomography is a suitable method for biometry of the canine eye, and a reference guide was established for eleven breeds. Eye size correlated with breed size and body weight. Because correlation between B-mode US and CT was shown, the obtained values can be applied in the clinical setting, for example, for the diagnosis of microphthalmos and buphthalmos.
authors.affiliation: Willows Veterinary Centre & Referral Service, Solihull, West Midlands, UK.
authors.forename: Carolin L H
authors.initials: CLH
authors.lastname: Chiwitt
authors.affiliation: Willows Veterinary Centre & Referral Service, Solihull, West Midlands, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Baines
authors.affiliation: Idexx Laboratories Limited, Wetherby, West Yorkshire, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Mahoney
authors.affiliation: Willows Veterinary Centre & Referral Service, Solihull, West Midlands, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Tanner
authors.affiliation: Eye Veterinary Clinic, Leominster, Herefordshire, UK.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Heinrich
authors.affiliation: Willows Veterinary Centre & Referral Service, Solihull, West Midlands, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Rhodes
authors.affiliation: Willows Veterinary Centre & Referral Service, Solihull, West Midlands, UK.
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Featherstone
mesh_terms: D000818:Animals; D001699:Biometry; D001835:Body Weight; D004285:Dogs; D005123:Eye / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D009929:Organ Size; D010865:Pilot Projects; D011446:Prospective Studies; D012015:Reference Standards; D012189:Retrospective Studies; D012756:Sheep; D013045:Species Specificity; D014057:Tomography, X-Ray Computed / Q000662:veterinary; D014463:Ultrasonography / Q000662:veterinary
keywords: canine; computed tomography; dog breeds; eye size; ocular biometry; ultrasound