The ocular structures are easily detectable by ultrasonography and MRI, because there are plenty amounts of fluid around the vitreous chamber and anterior chamber.

In this study, a total of ten normal domestic shorthair cats (DSH cats), 5 males, 5 females, weighing 3±1.09 kg, underwent ultrasonographic examination using a GE Voluson ultrasonography machine, and three-dimensional (3D) linear array transducers (5–10 MHz). MRI was performed with a 1.5 T GE scanner and a phased array human eye coil. The field of view ranged from 4 to 8 cm. In all cats, transverse, sagittal and dorsal spin-echo T1 and T2-weighted images were acquired.

The mean optical nerve diameter in males by 3D ultrasound and MRI were: 1.85 mm (SD=0.002), and in females it was 1.86 mm (SD=0.001). There weren't significant differences between ocular nerve measurements in male and female cats and left and right eyes using 3D ultrasound or MRI (p value <0.05).

The 3D ultrasound gives useful images for teaching and diagnostic purposes, and lesions of the caudal portion of the orbit (e.g., optic nerve atrophy) are better visualized by this technique. The results of the eye 3D US in cats showed marked advantages in image acquisition for interpretation of all aspects of the ocular structures. This study showed that using 3D US in veterinary ophthalmology may be better than MRI because the images of 3D US are completely flexible and you can see all voluntary views, the scanning time is very fast, and anaesthesia was not used in 3D US so that manipulation of animal patients is much easier.