Central corneal thickness measurements and ultrasonographic study of the growing equine eye.

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.

ANIMALS STUDIED

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).

PROCEDURE

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.

CONCLUSION

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.