title: Central corneal thickness measurements and ultrasonographic study of the growing equine eye.
abstract: OBJECTIVE
  The aim of this study was to determine the central corneal thickness (CCT) of healthy equine eyes with high-frequency ultrasound (HF) and ultrasound biomicroscopy (UBM) and to measure the axial dimensions with B-mode ultrasound. Additionally, the influence of the age on the measured dimensions of the globe was analyzed.
  
  
  METHODS
  Fifty warm blood horses (mean age 23.0 ± 21.12 months) were divided into 3 age groups (group 1: 0-6 months; group 2: ≥7-30 months; and group 3: ≥31-78 months).
  
  
  METHODS
  Corneal measurements were performed with a 22-MHz and a 50-MHz transducer. Crystalline lens thickness (CLT), vitreous chamber depth (VCD), and axial globe length (AGL) were measured at a frequency of 10 MHz. Anterior chamber depth (ACD) was calculated. The eyes were measured under general anesthesia nonrelated to this study.
  
  
  RESULTS
  The mean CCT of 50 eyes was 818 ± 41 μm. The mean values ± SD in mm for axial dimensions were AGL 34.7 ± 2.7, ACD 3.4 ± 0.7, CLT 10.0 ± 0.9, and VCD of 20.4 ± 1.5. A positive correlation with increasing age was found for all dimensions. No significant differences were found between the gender and the left or right eye.
  
  
  CONCLUSIONS
  HF and UBM are valuable high-resolution imaging tools for CCT measurements in horses. The here-obtained values support previous findings that a positive correlation with increasing age exists for CCT, ACD, CLT, VCD, and AGL in horse.
authors.affiliation: Small Animal Clinic, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
authors.forename: Lena E
authors.initials: LE
authors.lastname: Herbig
authors.affiliation: Small Animal Clinic, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
authors.forename: J Corinna
authors.initials: JC
authors.lastname: Eule
mesh_terms: D000818:Animals; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000254:growth & development; D005123:Eye / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000254:growth & development; D005260:Female; D006736:Horses / Q000033:anatomy & histology* / Q000254:growth & development; D008297:Male; D014463:Ultrasonography
keywords: axial dimensions; biometry; corneal development; eye; high-frequency ultrasound; horse