title: Ultrasound imaging of the anterior section of the eye of five different snake species.
abstract: BACKGROUND
  Nineteen clinically normal snakes: six ball pythons (Python regius), six Burmese pythons (Python bivittatus), one Children's python (Antaresia childreni), four Amazon tree boas (Corallus hortulanus), and two Malagasy ground boas (Acrantophis madagascariensis) were subjected to ultrasound imaging with 21 MHz (ball python) and 50 MHz (ball python, Burmese python, Children's python, Amazon tree boa, Malagasy ground boa) transducers in order to measure the different structures of the anterior segment in clinically normal snake eyes with the aim to review baseline values for clinically important ophthalmic structures. The ultrasonographic measurements included horizontal spectacle diameter, spectacle thickness, depth of sub-spectacular space and corneal thickness. For comparative purposes, a formalin-fixed head of a Burmese python was subjected to micro computed tomography.
  
  
  RESULTS
  In all snakes, the spectacle was thinner than the cornea. There was significant difference in spectacle diameter, and spectacle and corneal thickness between the Amazon tree boa and the Burmese and ball pythons. There was no difference in the depth of the sub-spectacular space. The results obtained in the Burmese python with the 50 MHz transducer were similar to the results obtained with micro computed tomography. Images acquired with the 21 MHz transducer included artifacts which may be misinterpreted as ocular structures.
  
  
  CONCLUSIONS
  Our measurements of the structures in the anterior segment of the eye can serve as orientative values for snakes examined for ocular diseases. In addition, we demonstrated that using a high frequency transducer minimizes the risk of misinterpreting artifacts as ocular structures.
authors.affiliation: Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Brendstrupgaardsvej, Aarhus N, Denmark. henrik@clin.au.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Lauridsen
authors.affiliation: Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej, Frederiksberg, Denmark. mds@zoo.dk.|Eye Pathology Institute, University of Copenhagen, Frederik V's Vej, Copenhagen, Denmark. mds@zoo.dk.
authors.forename: Mari-Ann O
authors.initials: MA
authors.lastname: Da Silva
authors.affiliation: Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Brendstrupgaardsvej, Aarhus N, Denmark. kasperhansen@clin.au.dk.
authors.forename: Kasper
authors.initials: K
authors.lastname: Hansen
authors.affiliation: Department of Biosciences, Zoophysiology, Aarhus University, DK-8000, Aarhus, Denmark. heidi.m.jensen@biology.au.dk.
authors.forename: Heidi M
authors.initials: HM
authors.lastname: Jensen
authors.affiliation: Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Brendstrupgaardsvej, Aarhus N, Denmark. mads@warming.as.|Department of Biosciences, Zoophysiology, Aarhus University, DK-8000, Aarhus, Denmark. mads@warming.as.
authors.forename: Mads
authors.initials: M
authors.lastname: Warming
authors.affiliation: Department of Biosciences, Zoophysiology, Aarhus University, DK-8000, Aarhus, Denmark. tobias.wang@biology.au.dk.
authors.forename: Tobias
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Brendstrupgaardsvej, Aarhus N, Denmark. michael@clin.au.dk.
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
mesh_terms: D000818:Animals; D017821:Boidae / Q000033:anatomy & histology; D003315:Cornea / Q000033:anatomy & histology; D005123:Eye / Q000000981:diagnostic imaging*; D012911:Snakes / Q000033:anatomy & histology*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography