The use of B-scan coupling with A-scan ultrasonography to characterize ocular biometry in canine absolute glaucoma

Abstract

This study was to investigate intraocular structures of canine absolute glaucomatous eyes using real time B-scan
ultrasonography in accordance with the amplitude mode. Ten normal eyes and twenty absolute glaucomatous eyes
were included in this study. Ocular biometry via closed-eye technique was performed using the Ultrascan® Imaging
System (Alcon Surgical Laboratory, Fort Worth, USA), with a 10 MHz mechanical sector probe. Changes of intraocular
structures were descriptively analyzed. Ocular biometry was measured, statistically analyzed and compared between
both groups. While mean lens thickness was comparable between normotensive and glaucomatous eyes, mean lens
equatorial length was higher in the latter group. Increased hyperechogenicity of lens was ultrasonographically
observed in dogs with absolute glaucoma. Axial globe length was significantly greater in the experimental group than
the control group (P<0.05). In relation to the appearance of the cone-shaped posterior wall, positive correlation between
intraocular pressure and axial globe length with statistical significance was noted (r=0.5, P<0.05). Retinal detachment
and lens displacement were also observed in absolute glaucomatous eyes. Not only does ultrasonography, with the 10
MHz frequency transducer, provides ocular biometry to specifically investigate changes of lens and the posterior
segment of the canine absolute glaucomatous eyes, it can lead to further selection of appropriate treatment and
awareness of post-treatment complications.