Ocular biometry by computed tomography in different dog breeds.

Area of Science:

• Veterinary Ophthalmology
• Medical Imaging
• Comparative Anatomy

Background:

• Accurate measurement of canine ocular dimensions is crucial for diagnosing conditions like microphthalmos and buphthalmos.
• Computed tomography (CT) offers a non-invasive method for detailed anatomical assessment.
• Establishing breed-specific reference ranges is essential for interpreting ocular measurements.

Purpose of the Study:

• To correlate B-mode ocular ultrasound (US) and CT measurements in a prospective pilot study.
• To establish a reliable CT-based method for canine ocular biometry.
• To create a reference guide for eleven dog breeds and analyze factors influencing eye size.

Main Methods:

• B-mode US and CT were performed on ten sheep cadaveric eyes.
• CT biometry was conducted on 100 adult dogs from eleven breeds, measuring eye length, width, and height in multiple planes.
• Retrospective analysis investigated correlations with body weight, gender, and skull type.

Main Results:

• B-mode US and CT measurements of sheep eyes showed good correlation (0.70-0.71).
• Canine eyes were characterized as oblate spheroids.
• A reference guide for eleven breeds was established, with larger breeds exhibiting significantly larger eyes than medium and small breeds (P < 0.01).
• Eye size positively correlated with body weight (0.74-0.82) but not gender or skull type.

Conclusions:

• CT is a suitable method for canine ocular biometry, with a reference guide now available for eleven breeds.
• Canine eye size is significantly influenced by breed size and body weight.
• The correlation between B-mode US and CT validates the use of these measurements in clinical settings for diagnosing ocular conditions.