B-Scan Biometry and Color Doppler Ultrasound Imaging of the Eye in Clinically Normal Donkeys (Equus asinus): Effect of Laterality, Maturity and Gender.
Authors: Wafy Mona N, Hassan Elham A, El-Maaty Amal M Abo, Abu-Seida Ashraf M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Ocular Ultrasonography Reference Values in Donkeys Establishing baseline diagnostic reference values for donkey eyes has been lacking despite widespread use of ocular ultrasonography in equine practice, prompting researchers to conduct B-scan biometry and colour Doppler imaging on 80 eyes from 40 clinically normal donkeys (both sexes and age groups) using a 12-MHz linear transducer. Measurements encompassed standard biometric parameters—anterior chamber depth, lens thickness, vitreous chamber depth, axial and longitudinal globe length, lens pole diameter and posterior wall thickness—alongside colour Doppler velocimetric indices including peak systolic velocity, end-diastolic velocity, resistive index and pulsatility index. Maturity significantly influenced structural measurements (axial globe length, longitudinal globe length and lens pole diameter all P<0.05), whilst gender affected vascular parameters (resistive index P=0.024, pulsatility index P<0.001, and volume flow per area P=0.008); notably, eye laterality produced no clinically meaningful differences in either biometry or blood flow characteristics. These findings provide clinicians with species-specific reference values that should improve diagnostic accuracy when evaluating donkeys presenting with ocular pathology, particularly enabling differentiation between developmental variation and genuine pathological change in an underserved population where ocular ultrasonography remains an underutilised diagnostic tool.
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Practical Takeaways
- •Establish age-adjusted reference ranges when using ultrasound to assess ocular development and changes in working donkeys
- •Consider gender-specific vascular parameters when evaluating ocular blood flow abnormalities, as velocimetric indices differ between males and females
- •Transpalpebral 12-MHz ultrasonography provides a practical, non-invasive diagnostic tool for detecting ocular pathology in donkeys without general anesthesia
Key Findings
- •Maturity significantly influenced axial globe length, longitudinal globe length, and lens pole diameter (P<0.05), while laterality and gender did not affect ocular biometry
- •Gender had significant effects on resistive index (P=0.024), pulsatility index (P<0.001), and volume flow per area (P=0.008)
- •Maturity significantly affected peak systolic velocity (P=0.027) and blood volume flow per distance and area (P<0.05)
- •B-scan biometry and color Doppler ultrasonography provided clinically useful reference values for evaluating donkey ocular health