title: In vivo measurement of central corneal thickness in normal chicks (Gallus gallus domesticus) with the optical low-coherence reflectometer.
abstract: OBJECTIVE
  To determine the practicability and accuracy of central corneal thickness (CCT) measurements in living chicks utilizing a noncontact, high-speed optical low-coherence reflectometer (OLCR) mounted on a slit lamp.
  
  
  METHODS
  Twelve male chicks (Gallus gallus domesticus). Procedures  Measurements of CCT were obtained in triplicate in 24 eyes of twelve 1-day-old anaesthetized chicks using OLCR. Every single measurement taken by OLCR consisted of the average result of 20 scans obtained within seconds. Additionally, corneal thickness was determined histologically after immersion fixation in Karnovsky's solution alone (20 eyes) or with a previous injection of the fixative into the anterior chamber before enucleation (4 eyes).
  
  
  RESULTS
  Central corneal thickness measurements using OLCR in 1-day-old living chicks provide a rapid and feasible examination technique. Mean CCT measured with OLCR (189.7 ± 3.34 μm) was significantly lower than histological measurements (242.1 ± 47.27 μm) in eyes with fixation in Karnovsky's solution (P = 0.0005). In eyes with additional injection of Karnovsky's fixative into the anterior chamber, mean histologically determined CCT was 195.2 ± 8.25 μm vs. 191.9 ± 8.90 μm with OLCR. A trend for a lower variance was found compared to the eyes that had only been immersion fixed.
  
  
  CONCLUSIONS
  Optical low-coherence reflectometry is an accurate examination technique to measure in vivo CCT in the eye of newborn chicks. The knowledge of the thickness of the chick cornea and the ability to obtain noninvasive, noncontact measurements of CCT in the living animal may be of interest for research and development of eye diseases in chick models.
authors: Department of Ophthalmology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland Department of Ophthalmology, University Hospital Basel, University of Basel, Basel, Switzerland.
authors: Christoph
authors: C
authors: Tappeiner
authors: David
authors: D
authors: Goldblum
authors: Konstantinos
authors: K
authors: Katsoulis
authors: Gian-Marco
authors: GM
authors: Sarra
authors: Beatrice E
authors: BE
authors: Frueh
mesh_terms: D000818:Animals; D002645:Chickens / Q000033:anatomy & histology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation / Q000662:veterinary*; D008297:Male; D003313:Zea mays / Q000033:anatomy & histology*