title: Variance of speed of sound and correlation with acoustic impedance in canine corneas.
abstract: The clinical standard for measuring corneal thickness is ultrasound pachymetry that assumes a constant speed of sound. The purpose of this study was to examine the variance of speed of sound and its relationship with acoustic impedance in healthy eyes of canines with a large age span. Corneal speed of sound and acoustic impedance were measured in 34 canine eyes at room temperature (21 ± 1°C). The mean speed of sound was 1577 ± 10 m/s ranging from 1553 to 1594 m/s. There was a strong correlation between speed of sound and acoustic impedance (R = 0.84, p < 0.001). Corneal speed of sound had a small variance in healthy canines over 1-year-old, but was significantly lower in younger canines suggesting an age effect. The strong correlation between corneal speed of sound and acoustic impedance may offer a potential means to noninvasively detect abnormal speed of sound for more accurate corneal thickness estimation.
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Junhua
authors.initials: J
authors.lastname: Tang
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
mesh_terms: D000162:Acoustics; D000367:Age Factors; D000818:Animals; D003315:Cornea / Q000000981:diagnostic imaging*; D004285:Dogs; D015203:Reproducibility of Results; D013018:Sound Spectrography; D014463:Ultrasonography